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Sample records for two-parameter logistic item

  1. Accuracy of Parameter Estimation in Gibbs Sampling under the Two-Parameter Logistic Model.

    Science.gov (United States)

    Kim, Seock-Ho; Cohen, Allan S.

    The accuracy of Gibbs sampling, a Markov chain Monte Carlo procedure, was considered for estimation of item and ability parameters under the two-parameter logistic model. Memory test data were analyzed to illustrate the Gibbs sampling procedure. Simulated data sets were analyzed using Gibbs sampling and the marginal Bayesian method. The marginal…

  2. An Alternative Three-Parameter Logistic Item Response Model.

    Science.gov (United States)

    Pashley, Peter J.

    Birnbaum's three-parameter logistic function has become a common basis for item response theory modeling, especially within situations where significant guessing behavior is evident. This model is formed through a linear transformation of the two-parameter logistic function in order to facilitate a lower asymptote. This paper discusses an…

  3. Effects of Initial Values and Convergence Criterion in the Two-Parameter Logistic Model When Estimating the Latent Distribution in BILOG-MG 3.

    Directory of Open Access Journals (Sweden)

    Ingo W Nader

    Full Text Available Parameters of the two-parameter logistic model are generally estimated via the expectation-maximization algorithm, which improves initial values for all parameters iteratively until convergence is reached. Effects of initial values are rarely discussed in item response theory (IRT, but initial values were recently found to affect item parameters when estimating the latent distribution with full non-parametric maximum likelihood. However, this method is rarely used in practice. Hence, the present study investigated effects of initial values on item parameter bias and on recovery of item characteristic curves in BILOG-MG 3, a widely used IRT software package. Results showed notable effects of initial values on item parameters. For tighter convergence criteria, effects of initial values decreased, but item parameter bias increased, and the recovery of the latent distribution worsened. For practical application, it is advised to use the BILOG default convergence criterion with appropriate initial values when estimating the latent distribution from data.

  4. Generalized Fiducial Inference for Binary Logistic Item Response Models.

    Science.gov (United States)

    Liu, Yang; Hannig, Jan

    2016-06-01

    Generalized fiducial inference (GFI) has been proposed as an alternative to likelihood-based and Bayesian inference in mainstream statistics. Confidence intervals (CIs) can be constructed from a fiducial distribution on the parameter space in a fashion similar to those used with a Bayesian posterior distribution. However, no prior distribution needs to be specified, which renders GFI more suitable when no a priori information about model parameters is available. In the current paper, we apply GFI to a family of binary logistic item response theory models, which includes the two-parameter logistic (2PL), bifactor and exploratory item factor models as special cases. Asymptotic properties of the resulting fiducial distribution are discussed. Random draws from the fiducial distribution can be obtained by the proposed Markov chain Monte Carlo sampling algorithm. We investigate the finite-sample performance of our fiducial percentile CI and two commonly used Wald-type CIs associated with maximum likelihood (ML) estimation via Monte Carlo simulation. The use of GFI in high-dimensional exploratory item factor analysis was illustrated by the analysis of a set of the Eysenck Personality Questionnaire data.

  5. Ramsay-Curve Item Response Theory for the Three-Parameter Logistic Item Response Model

    Science.gov (United States)

    Woods, Carol M.

    2008-01-01

    In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters of a unidimensional item response model using marginal maximum likelihood estimation. This study evaluates RC-IRT for the three-parameter logistic (3PL) model with comparisons to the normal model and to the empirical…

  6. Detecting Differential Item Functioning Using Logistic Regression Procedures.

    Science.gov (United States)

    Swaminathan, Hariharan; Rogers, H. Jane

    1990-01-01

    A logistic regression model for characterizing differential item functioning (DIF) between two groups is presented. A distinction is drawn between uniform and nonuniform DIF in terms of model parameters. A statistic for testing the hypotheses of no DIF is developed, and simulation studies compare it with the Mantel-Haenszel procedure. (Author/TJH)

  7. 41 CFR 101-26.605 - Items other than petroleum products and electronic items available from the Defense Logistics...

    Science.gov (United States)

    2010-07-01

    ... petroleum products and electronic items available from the Defense Logistics Agency. 101-26.605 Section 101... available from the Defense Logistics Agency. Agencies required to use GSA supply sources should also use... Logistics Agency, the catalog will contain only those items in Federal supply classification classes which...

  8. Two-parameter logistic and Weibull equations provide better fits to survival data from isogenic populations of Caenorhabditis elegans in axenic culture than does the Gompertz model.

    Science.gov (United States)

    Vanfleteren, J R; De Vreese, A; Braeckman, B P

    1998-11-01

    We have fitted Gompertz, Weibull, and two- and three-parameter logistic equations to survival data obtained from 77 cohorts of Caenorhabditis elegans in axenic culture. Statistical analysis showed that the fitting ability was in the order: three-parameter logistic > two-parameter logistic = Weibull > Gompertz. Pooled data were better fit by the logistic equations, which tended to perform equally well as population size increased, suggesting that the third parameter is likely to be biologically irrelevant. Considering restraints imposed by the small population sizes used, we simply conclude that the two-parameter logistic and Weibull mortality models for axenically grown C. elegans generally provided good fits to the data, whereas the Gompertz model was inappropriate in many cases. The survival curves of several short- and long-lived mutant strains could be predicted by adjusting only the logistic curve parameter that defines mean life span. We conclude that life expectancy is genetically determined; the life span-altering mutations reported in this study define a novel mean life span, but do not appear to fundamentally alter the aging process.

  9. An Introduction to the DA-T Gibbs Sampler for the Two-Parameter Logistic (2PL Model and Beyond

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    Gunter Maris

    2005-01-01

    Full Text Available The DA-T Gibbs sampler is proposed by Maris and Maris (2002 as a Bayesian estimation method for a wide variety of Item Response Theory (IRT models. The present paper provides an expository account of the DAT Gibbs sampler for the 2PL model. However, the scope is not limited to the 2PL model. It is demonstrated how the DA-T Gibbs sampler for the 2PL may be used to build, quite easily, Gibbs samplers for other IRT models. Furthermore, the paper contains a novel, intuitive derivation of the Gibbs sampler and could be read for a graduate course on sampling.

  10. A Note on the Item Information Function of the Four-Parameter Logistic Model

    Science.gov (United States)

    Magis, David

    2013-01-01

    This article focuses on four-parameter logistic (4PL) model as an extension of the usual three-parameter logistic (3PL) model with an upper asymptote possibly different from 1. For a given item with fixed item parameters, Lord derived the value of the latent ability level that maximizes the item information function under the 3PL model. The…

  11. A Note on the Item Information Function of the Four-Parameter Logistic Model

    Science.gov (United States)

    Magis, David

    2013-01-01

    This article focuses on four-parameter logistic (4PL) model as an extension of the usual three-parameter logistic (3PL) model with an upper asymptote possibly different from 1. For a given item with fixed item parameters, Lord derived the value of the latent ability level that maximizes the item information function under the 3PL model. The…

  12. 41 CFR 101-26.603 - Electronic items available from the Defense Logistics Agency.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Electronic items available from the Defense Logistics Agency. 101-26.603 Section 101-26.603 Public Contracts and Property... items available from the Defense Logistics Agency. Executive agencies shall satisfy their requirements...

  13. Detecting DIF in Polytomous Items Using MACS, IRT and Ordinal Logistic Regression

    Science.gov (United States)

    Elosua, Paula; Wells, Craig

    2013-01-01

    The purpose of the present study was to compare the Type I error rate and power of two model-based procedures, the mean and covariance structure model (MACS) and the item response theory (IRT), and an observed-score based procedure, ordinal logistic regression, for detecting differential item functioning (DIF) in polytomous items. A simulation…

  14. Item Vector Plots for the Multidimensional Three-Parameter Logistic Model

    Science.gov (United States)

    Bryant, Damon; Davis, Larry

    2011-01-01

    This brief technical note describes how to construct item vector plots for dichotomously scored items fitting the multidimensional three-parameter logistic model (M3PLM). As multidimensional item response theory (MIRT) shows promise of being a very useful framework in the test development life cycle, graphical tools that facilitate understanding…

  15. A Generalized Logistic Regression Procedure to Detect Differential Item Functioning among Multiple Groups

    Science.gov (United States)

    Magis, David; Raiche, Gilles; Beland, Sebastien; Gerard, Paul

    2011-01-01

    We present an extension of the logistic regression procedure to identify dichotomous differential item functioning (DIF) in the presence of more than two groups of respondents. Starting from the usual framework of a single focal group, we propose a general approach to estimate the item response functions in each group and to test for the presence…

  16. Power and Sample Size Calculations for Logistic Regression Tests for Differential Item Functioning

    Science.gov (United States)

    Li, Zhushan

    2014-01-01

    Logistic regression is a popular method for detecting uniform and nonuniform differential item functioning (DIF) effects. Theoretical formulas for the power and sample size calculations are derived for likelihood ratio tests and Wald tests based on the asymptotic distribution of the maximum likelihood estimators for the logistic regression model.…

  17. Power and Sample Size Calculations for Logistic Regression Tests for Differential Item Functioning

    Science.gov (United States)

    Li, Zhushan

    2014-01-01

    Logistic regression is a popular method for detecting uniform and nonuniform differential item functioning (DIF) effects. Theoretical formulas for the power and sample size calculations are derived for likelihood ratio tests and Wald tests based on the asymptotic distribution of the maximum likelihood estimators for the logistic regression model.…

  18. Differential item functioning (DIF) analyses of health-related quality of life instruments using logistic regression

    DEFF Research Database (Denmark)

    Scott, Neil W; Fayers, Peter M; Aaronson, Neil K

    2010-01-01

    Differential item functioning (DIF) methods can be used to determine whether different subgroups respond differently to particular items within a health-related quality of life (HRQoL) subscale, after allowing for overall subgroup differences in that scale. This article reviews issues that arise ...... when testing for DIF in HRQoL instruments. We focus on logistic regression methods, which are often used because of their efficiency, simplicity and ease of application....

  19. Differential item functioning (DIF) analyses of health-related quality of life instruments using logistic regression

    DEFF Research Database (Denmark)

    Scott, Neil W.; Fayers, Peter M.; Aaronson, Neil K.

    2010-01-01

    Differential item functioning (DIF) methods can be used to determine whether different subgroups respond differently to particular items within a health-related quality of life (HRQoL) subscale, after allowing for overall subgroup differences in that scale. This article reviews issues that arise...... when testing for DIF in HRQoL instruments. We focus on logistic regression methods, which are often used because of their efficiency, simplicity and ease of application....

  20. Confidence Bands for the Three-Parameter Logistic Item Response Curve.

    Science.gov (United States)

    Lord, Frederic M.; Pashley, Peter J.

    A large sample method for obtaining asymptotic simultaneous confidence bands for a three-parameter logistic response curve is described. Simultaneous confidence bands indicate the sampling variation of item response curves relative to a fitted function. A procedure is given which requires as input maximum likelihood parameter estimates and an…

  1. Examining item-position effects in large-scale assessment using the Linear Logistic Test Model

    Directory of Open Access Journals (Sweden)

    CHRISTINE HOHENSINN

    2008-09-01

    Full Text Available When administering large-scale assessments, item-position effects are of particular importance because the applied test designs very often contain several test booklets with the same items presented at different test positions. Establishing such position effects would be most critical; it would mean that the estimated item parameters do not depend exclusively on the items’ difficulties due to content but also on their presentation positions. As a consequence, item calibration would be biased. By means of the linear logistic test model (LLTM, item-position effects can be tested. In this paper, the results of a simulation study demonstrating how LLTM is indeed able to detect certain position effects in the framework of a large-scale assessment are presented first. Second, empirical item-position effects of a specific large-scale competence assessment in mathematics (4th grade students are analyzed using the LLTM. The results indicate that a small fatigue effect seems to take place. The most important consequence of the given paper is that it is advisable to try pertinent simulation studies before an analysis of empirical data takes place; the reason is, that for the given example, the suggested Likelihood-Ratio test neither holds the nominal type-I-risk, nor qualifies as “robust”, and furthermore occasionally shows very low power.

  2. The Impact of Three Factors on the Recovery of Item Parameters for the Three-Parameter Logistic Model

    Science.gov (United States)

    Kim, Kyung Yong; Lee, Won-Chan

    2017-01-01

    This article provides a detailed description of three factors (specification of the ability distribution, numerical integration, and frame of reference for the item parameter estimates) that might affect the item parameter estimation of the three-parameter logistic model, and compares five item calibration methods, which are combinations of the…

  3. Analysis Test of Understanding of Vectors with the Three-Parameter Logistic Model of Item Response Theory and Item Response Curves Technique

    Science.gov (United States)

    Rakkapao, Suttida; Prasitpong, Singha; Arayathanitkul, Kwan

    2016-01-01

    This study investigated the multiple-choice test of understanding of vectors (TUV), by applying item response theory (IRT). The difficulty, discriminatory, and guessing parameters of the TUV items were fit with the three-parameter logistic model of IRT, using the parscale program. The TUV ability is an ability parameter, here estimated assuming…

  4. Analysis test of understanding of vectors with the three-parameter logistic model of item response theory and item response curves technique

    Science.gov (United States)

    Rakkapao, Suttida; Prasitpong, Singha; Arayathanitkul, Kwan

    2016-12-01

    This study investigated the multiple-choice test of understanding of vectors (TUV), by applying item response theory (IRT). The difficulty, discriminatory, and guessing parameters of the TUV items were fit with the three-parameter logistic model of IRT, using the parscale program. The TUV ability is an ability parameter, here estimated assuming unidimensionality and local independence. Moreover, all distractors of the TUV were analyzed from item response curves (IRC) that represent simplified IRT. Data were gathered on 2392 science and engineering freshmen, from three universities in Thailand. The results revealed IRT analysis to be useful in assessing the test since its item parameters are independent of the ability parameters. The IRT framework reveals item-level information, and indicates appropriate ability ranges for the test. Moreover, the IRC analysis can be used to assess the effectiveness of the test's distractors. Both IRT and IRC approaches reveal test characteristics beyond those revealed by the classical analysis methods of tests. Test developers can apply these methods to diagnose and evaluate the features of items at various ability levels of test takers.

  5. Item Response Theory with Covariates (IRT-C): Assessing Item Recovery and Differential Item Functioning for the Three-Parameter Logistic Model

    Science.gov (United States)

    Tay, Louis; Huang, Qiming; Vermunt, Jeroen K.

    2016-01-01

    In large-scale testing, the use of multigroup approaches is limited for assessing differential item functioning (DIF) across multiple variables as DIF is examined for each variable separately. In contrast, the item response theory with covariate (IRT-C) procedure can be used to examine DIF across multiple variables (covariates) simultaneously. To…

  6. Results of Item Parameter Estimation Using LOGIST 5 on Simulated Data.

    Science.gov (United States)

    1984-12-01

    against the Theoretical Individual Parameters. Three-Parameter Logistic Model Is Assumed. Case 2, 500 Subject Case. (L inear Regresion of Son 8 Is...Parameters. Three-Parameter Logistic Model Is , ’." Assumed. Case 1, 2,000 Subject Case. ( Lineal Regvussion of on 6 Is Plotted by a Dotted Line

  7. A Formulation of the Mantel-Haenszel Differential Item Functioning Parameter with Practical Implications. Statistical Report. LSAC Research Report Series.

    Science.gov (United States)

    Roussos, Louis A.; Schnipke, Deborah L.; Pashley, Peter J.

    The Mantel-Haenszel (MH) differential item functioning (DIF) parameter for uniform DIF is well defined when item responses follow the two-parameter-logistic (2PPL) item response function (IRF), but not when they follow the three-parameter-logistic (3PL) IRF, the model typically used with multiple choice items. This research report presents a…

  8. Ensuring the Visibility and Traceability of Items through Logistics Chain of Automotive Industry Based on AutoEPCNet Using

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    Pavel Stasa

    2016-01-01

    Full Text Available Traceability in logistics is the capability of the participants to trace the products throughout the supply chain by means of either the product and/or container identifiers in a forward and/or backward direction. In today's competitive economic environment, traceability is a key concept related to all products and all types of supply chains. The goal of this paper is to describe development of application that enables to create and share information about the physical movement and status of products as they travel throughout the supply chain. The main purpose of this paper is to describe the development of RFID based track and trace system for ensuring the visibility and traceability of items in logistics chain especially in automotive industry. The proposed solution is based on EPCglobal Network Architecture.

  9. Bayesian Ability Estimation via 3PL (Three-Parameter Logistic) with Partially Known Item Parameters

    Science.gov (United States)

    1988-08-31

    TOE 14& .TQ r , o ORT (Year, Month, Day) 15. PAE COUNT :eFROM anL__ T 0 &A~ ’-1~~Jg 34 16 SUPPLEMENTARY NOTATION 17 COSATI CODES I 18. SUBJECT TERMS...jp(Ojz, )p( Jz)d, (11) r ’,4 where, from the conditional independence if x and y given C, p(CIz) = p(xI )p( jY)/p(x1Y) (12) and p(Olz,) = p (xl)¢(9)/p(x...Approximate Bayesian methods Trabajos Estadistica 31, 223-237. Lord, F.M. (1980). Applications of Item Response Theory to Practical Testing Problems

  10. Binary Logistic Regression Analysis for Detecting Differential Item Functioning: Effectiveness of R[superscript 2] and Delta Log Odds Ratio Effect Size Measures

    Science.gov (United States)

    Hidalgo, Mª Dolores; Gómez-Benito, Juana; Zumbo, Bruno D.

    2014-01-01

    The authors analyze the effectiveness of the R[superscript 2] and delta log odds ratio effect size measures when using logistic regression analysis to detect differential item functioning (DIF) in dichotomous items. A simulation study was carried out, and the Type I error rate and power estimates under conditions in which only statistical testing…

  11. Binary Logistic Regression Analysis for Detecting Differential Item Functioning: Effectiveness of R[superscript 2] and Delta Log Odds Ratio Effect Size Measures

    Science.gov (United States)

    Hidalgo, Mª Dolores; Gómez-Benito, Juana; Zumbo, Bruno D.

    2014-01-01

    The authors analyze the effectiveness of the R[superscript 2] and delta log odds ratio effect size measures when using logistic regression analysis to detect differential item functioning (DIF) in dichotomous items. A simulation study was carried out, and the Type I error rate and power estimates under conditions in which only statistical testing…

  12. A Comparison of Mantel-Haenszel Differential Item Functioning Parameters. LSAC Research Report Series.

    Science.gov (United States)

    Schnipke, Deborah L.; Roussos, Louis A.; Pashley, Peter J.

    Differential item functioning (DIF) analyses are conducted to investigate how items function in various subgroups. The Mantel-Haenszel (MH) DIF statistic is used at the Law School Admission Council and other testing companies. When item functioning can be well-described in terms of a one- or two-parameter logistic item response theory (IRT) model…

  13. Research of Readability and Identification of the Items in the Postal and Logistics Environment

    Directory of Open Access Journals (Sweden)

    Kolarovszki Peter

    2014-09-01

    Full Text Available This article deals with RFID technology, which is a part of automatic identification and data capture. Nowadays, the identification of parcels in postal sector is carried through barcodes. In this article we would like specify, how can be postal parcels located in postal container identified in the transmission process of postal main processing centre by UHF RFID technology. All results are verified by measurement in our AIDC laboratory, which is located at the University of Žilina. Our research contains 12 different types of orientation tags and antennas and more than 1000 tests. Our identification performance was close to 100%. All tested parcels were located in postal container. The results of our research bring the new point of view and indicate the ways using of UHF RFID technology in postal applications. At the end of this article the utilization of the RFID technology in postal logistics chain is characterized.

  14. Pretest Item Analyses Using Polynomial Logistic Regression: An Approach to Small Sample Calibration Problems Associated with Computerized Adaptive Testing.

    Science.gov (United States)

    Patsula, Liane N.; Pashley, Peter J.

    Many large-scale testing programs routinely pretest new items alongside operational (or scored) items to determine their empirical characteristics. If these pretest items pass certain statistical criteria, they are placed into an operational item pool; otherwise they are edited and re-pretested or simply discarded. In these situations, reliable…

  15. A lognormal model for response times on test items

    NARCIS (Netherlands)

    van der Linden, Willem J.

    2006-01-01

    A lognormal model for the response times of a person on a set of test items is investigated. The model has a parameter structure analogous to the two-parameter logistic response models in item response theory, with a parameter for the speed of each person as well as parameters for the time intensity

  16. Limits on Log Odds Ratios for Unidimensional Item Response Theory Models

    Science.gov (United States)

    Haberman, Shelby J.; Holland, Paul W.; Sinharay, Sandip

    2007-01-01

    Bounds are established for log odds ratios (log cross-product ratios) involving pairs of items for item response models. First, expressions for bounds on log odds ratios are provided for one-dimensional item response models in general. Then, explicit bounds are obtained for the Rasch model and the two-parameter logistic (2PL) model. Results are…

  17. Three Statistical Testing Procedures in Logistic Regression: Their Performance in Differential Item Functioning (DIF) Investigation. Research Report. ETS RR-09-35

    Science.gov (United States)

    Paek, Insu

    2009-01-01

    Three statistical testing procedures well-known in the maximum likelihood approach are the Wald, likelihood ratio (LR), and score tests. Although well-known, the application of these three testing procedures in the logistic regression method to investigate differential item function (DIF) has not been rigorously made yet. Employing a variety of…

  18. An Evaluation of One- and Three-Parameter Logistic Tailored Testing Procedures for Use with Small Item Pools.

    Science.gov (United States)

    McKinley, Robert L.; Reckase, Mark D.

    A two-stage study was conducted to compare the ability estimates yielded by tailored testing procedures based on the one-parameter logistic (1PL) and three-parameter logistic (3PL) models. The first stage of the study employed real data, while the second stage employed simulated data. In the first stage, response data for 3,000 examinees were…

  19. Differential Item Functioning Analysis Using a Mixture 3-Parameter Logistic Model with a Covariate on the TIMSS 2007 Mathematics Test

    Science.gov (United States)

    Choi, Youn-Jeng; Alexeev, Natalia; Cohen, Allan S.

    2015-01-01

    The purpose of this study was to explore what may be contributing to differences in performance in mathematics on the Trends in International Mathematics and Science Study 2007. This was done by using a mixture item response theory modeling approach to first detect latent classes in the data and then to examine differences in performance on items…

  20. The Prediction of Item Parameters Based on Classical Test Theory and Latent Trait Theory

    Science.gov (United States)

    Anil, Duygu

    2008-01-01

    In this study, the prediction power of the item characteristics based on the experts' predictions on conditions try-out practices cannot be applied was examined for item characteristics computed depending on classical test theory and two-parameters logistic model of latent trait theory. The study was carried out on 9914 randomly selected students…

  1. On Bayesian Rules for Selecting 3PL Binary Items for Criterion-Referenced Interpretations and Creating Booklets for Bookmark Standard Setting.

    Science.gov (United States)

    Huynh, Huynh

    By noting that a Rasch or two parameter logistic (2PL) item belongs to the exponential family of random variables and that the probability density function (pdf) of the correct response (X=1) and the incorrect response (X=0) are symmetric with respect to the vertical line at the item location, it is shown that the conjugate prior for ability is…

  2. Comparison of Multidimensional Item Response Models: Multivariate Normal Ability Distributions versus Multivariate Polytomous Ability Distributions. Research Report. ETS RR-08-45

    Science.gov (United States)

    Haberman, Shelby J.; von Davier, Matthias; Lee, Yi-Hsuan

    2008-01-01

    Multidimensional item response models can be based on multivariate normal ability distributions or on multivariate polytomous ability distributions. For the case of simple structure in which each item corresponds to a unique dimension of the ability vector, some applications of the two-parameter logistic model to empirical data are employed to…

  3. Renormalizable two-parameter piecewise isometries.

    Science.gov (United States)

    Lowenstein, J H; Vivaldi, F

    2016-06-01

    We exhibit two distinct renormalization scenarios for two-parameter piecewise isometries, based on 2π/5 rotations of a rhombus and parameter-dependent translations. Both scenarios rely on the recently established renormalizability of a one-parameter triangle map, which takes place if and only if the parameter belongs to the algebraic number field K=Q(5) associated with the rotation matrix. With two parameters, features emerge which have no counterpart in the single-parameter model. In the first scenario, we show that renormalizability is no longer rigid: whereas one of the two parameters is restricted to K, the second parameter can vary continuously over a real interval without destroying self-similarity. The mechanism involves neighbouring atoms which recombine after traversing distinct return paths. We show that this phenomenon also occurs in the simpler context of Rauzy-Veech renormalization of interval exchange transformations, here regarded as parametric piecewise isometries on a real interval. We explore this analogy in some detail. In the second scenario, which involves two-parameter deformations of a three-parameter rhombus map, we exhibit a weak form of rigidity. The phase space splits into several (non-convex) invariant components, on each of which the renormalization still has a free parameter. However, the foliations of the different components are transversal in parameter space; as a result, simultaneous self-similarity of the component maps requires that both of the original parameters belong to the field K.

  4. General collision branching processes with two parameters

    Institute of Scientific and Technical Information of China (English)

    CHEN AnYue; LI JunPing

    2009-01-01

    A new class of branching models, the general collision branching processes with two parameters, is considered in this paper. For such models, it is necessary to evaluate the absorbing probabilities and mean extinction times for both absorbing states. Regularity and uniqueness criteria are firstly established. Explicit expressions are then obtained for the extinction probability vector, the mean extinction times and the conditional mean extinction times. The explosion behavior of these models is investigated and an explicit expression for mean explosion time is established. The mean global holding time is also obtained. It is revealed that these properties are substantially different between the super-explosive and sub-explosive cases.

  5. General collision branching processes with two parameters

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new class of branching models,the general collision branching processes with two parameters,is considered in this paper.For such models,it is necessary to evaluate the absorbing probabilities and mean extinction times for both absorbing states.Regularity and uniqueness criteria are firstly established.Explicit expressions are then obtained for the extinction probability vector,the mean extinction times and the conditional mean extinction times.The explosion behavior of these models is investigated and an explicit expression for mean explosion time is established.The mean global holding time is also obtained.It is revealed that these properties are substantially different between the super-explosive and sub-explosive cases.

  6. Integral points in two-parameter orbits

    CERN Document Server

    Corvaja, Pietro; Tucker, Thomas J; Zannier, Umberto

    2012-01-01

    Let K be a number field, let f: P_1 --> P_1 be a nonconstant rational map of degree greater than 1, let S be a finite set of places of K, and suppose that u, w in P_1(K) are not preperiodic under f. We prove that the set of (m,n) in N^2 such that f^m(u) is S-integral relative to f^n(w) is finite and effectively computable. This may be thought of as a two-parameter analog of a result of Silverman on integral points in orbits of rational maps. This issue can be translated in terms of integral points on an open subset of P_1^2; then one can apply a modern version of the method of Runge, after increasing the number of components at infinity by iterating the rational map. Alternatively, an ineffective result comes from a well-known theorem of Vojta.

  7. Differential item functioning due to gender between depression and anxiety items among Chilean adolescents.

    Science.gov (United States)

    Bares, Cristina; Andrade, Fernando; Delva, Jorge; Grogan-Kaylor, Andrew; Kamata, Akihito

    2012-07-01

    Although much is known about the higher prevalence of anxiety and depressive disorders among adolescent females, less is known about the differential item endorsement due to gender in items of scales commonly used to measure anxiety and depression. We conducted a study to examine if adolescent males and females from Chile differed on how they endorsed the items of the Youth Self Report (YSR) anxious/depressed problem scale. We used data from a cross-sectional sample consisting of 925 participants (mean age = 14, SD 1.3, 49% females) of low to lower-middle socioeconomic status. A two-parameter logistic (2PL) IRT DIF model was fit. s revealed differential item functioning (DIF) by gender for six of the 13 items, with adolescent females being more likely to endorse a depression item while males were found more likely to endorse anxiety items. Findings suggest that items found in commonly used measures of anxiety and depression symptoms may not equally capture the true levels of these behavioural problems in adolescent males and females. Given the high levels of mental disorders in Chile and the surrounding countries, further attention should be focused on increasing the number of empirical studies examining potential gender differences in the assessment of mental health problems among Latin American populations to better aid our understanding of the phenomenology and determinants of these problems in the region.

  8. An EOQ Model with Two-Parameter Weibull Distribution Deterioration and Price-Dependent Demand

    Science.gov (United States)

    Mukhopadhyay, Sushanta; Mukherjee, R. N.; Chaudhuri, K. S.

    2005-01-01

    An inventory replenishment policy is developed for a deteriorating item and price-dependent demand. The rate of deterioration is taken to be time-proportional and the time to deterioration is assumed to follow a two-parameter Weibull distribution. A power law form of the price dependence of demand is considered. The model is solved analytically…

  9. Impact of Missing Data on the Detection of Differential Item Functioning: The Case of Mantel-Haenszel and Logistic Regression Analysis

    Science.gov (United States)

    Robitzsch, Alexander; Rupp, Andre A.

    2009-01-01

    This article describes the results of a simulation study to investigate the impact of missing data on the detection of differential item functioning (DIF). Specifically, it investigates how four methods for dealing with missing data (listwise deletion, zero imputation, two-way imputation, response function imputation) interact with two methods of…

  10. MODERATING ABILITY OF ITEM RESPONSE THEORY THROUGH PRIOR GUESSING PARAMETER

    Directory of Open Access Journals (Sweden)

    Siow Hoo Leong

    2013-01-01

    Full Text Available A psycho-technology approach to discouraging guessing in multiple-choice formatted item can be done through reducing the a priori guessing probability of an item. This study proposes a psychometrics framework of Item Response Theory (IRT to model the effect of having various priori guessing probabilities across different items. A prior guessing parameter is proposed to serves as a moderator of the ability parameter in the two parameter logistic IRT. The results show that the proposed prior guessing parameter successfully moderates the ability parameters of the subjects with different degrees of guessing. However, the prior guessing parameter is insensitive when the performance pattern is mixed within the testlet but similar across testlet with different priori guessing probabilities.

  11. 应急救援物流中物资分发点多目标排队选址优化%Multi-objective queuing location optimization for item distribution spots in emergency relief logistics

    Institute of Scientific and Technical Information of China (English)

    彭翀; 汪传旭; 郭胜童

    2011-01-01

    基于模糊数学、排队理论与选址理论,建立了应急救援物流中物资分发点的多目标模糊排队选址优化模型,其中:受灾点的需求率和物资分发点的服务率为模糊数,物资分发点建立成本最小和救援反应时间最短为目标函数.设计了模型的求解算法,确定了物资分发点的选址以及各个分发点所覆盖的受灾点区域范围.结合具体算例,验证了模型的实用性,并分析了物资分发点应急服务能力对救援效果的影响.%Based on fuzzy mathematics, queuing theory and location theory, a model is introduced into solving the problems about item distribution spots location optimization in emergency relief logistics where the demand rates of disaster spots and service rates of item distribution spots are fuzzy numbers. The proposed model aims at jointly minimi zing the setup costs for item distribution spots and relief response time. The algorithms are presented to set the proposed model to determine the location and covering scope of item distribution spots. A numerical example is given to demonstrate the effectiveness of the proposed model and the impact of service capacity of item distribution spots on re lief performance is analyzed.

  12. Transformation of state space for two-parameter Markov processes

    Institute of Scientific and Technical Information of China (English)

    周健伟

    1996-01-01

    Let X=(X) be a two-parameter *-Markov process with a transition function (p1, p2, p), where X, takes values in the state space (Er,), T=[0,)2. For each r T, let f, be a measurable transformation of (E,) into the state space (E’r, ). Set Y,=f,(X,), r T. A sufficient condition is given for the process Y=(Yr) still to be a two-parameter *-Markov process with a transition function in terms of transition function (p1, p2, p) and fr. For *-Markov families of two-parameter processes with a transition function, a similar problem is also discussed.

  13. Comprehensive Logistics

    CERN Document Server

    Gudehus, Timm

    2012-01-01

    Modern logistics comprises operative logistics, analytical logistics and management of logistic networks. Central task of operative logistics is the efficient supply of required goods at the right place within the right time. Tasks of analytical logistics are designing optimal networks and systems, developing strategies for planning, scheduling and operation, and organizing efficient order and performance processes. Logistic management plans, implements and operates logistic networks and schedules orders, stocks and resources. This reference-book offers a unique survey of modern logistics. It contains proven strategies, rules and tools for the solution of a multitude of logistic problems. The analytically derived algorithms and formulas can be used for the computer-based planning of logistic systems and for the dynamic scheduling of orders and resources in supply networks. They enable significant improvements of performance, quality and costs. Their application is demonstrated by several examples from industr...

  14. Measuring organizational effectiveness in information and communication technology companies using item response theory.

    Science.gov (United States)

    Trierweiller, Andréa Cristina; Peixe, Blênio César Severo; Tezza, Rafael; Pereira, Vera Lúcia Duarte do Valle; Pacheco, Waldemar; Bornia, Antonio Cezar; de Andrade, Dalton Francisco

    2012-01-01

    The aim of this paper is to measure the effectiveness of the organizations Information and Communication Technology (ICT) from the point of view of the manager, using Item Response Theory (IRT). There is a need to verify the effectiveness of these organizations which are normally associated to complex, dynamic, and competitive environments. In academic literature, there is disagreement surrounding the concept of organizational effectiveness and its measurement. A construct was elaborated based on dimensions of effectiveness towards the construction of the items of the questionnaire which submitted to specialists for evaluation. It demonstrated itself to be viable in measuring organizational effectiveness of ICT companies under the point of view of a manager through using Two-Parameter Logistic Model (2PLM) of the IRT. This modeling permits us to evaluate the quality and property of each item placed within a single scale: items and respondents, which is not possible when using other similar tools.

  15. Bubbling and bistability in two parameter discrete systems

    Indian Academy of Sciences (India)

    G Ambika; N V Sujatha

    2000-05-01

    We present a graphical analysis of the mechanisms underlying the occurrences of bubbling sequences and bistability regions in the bifurcation scenario of a special class of one dimensional two parameter maps. The main result of the analysis is that whether it is bubbling or bistability is decided by the sign of the third derivative at the inflection point of the map function.

  16. Optimal Two Parameter Bounds for the Seiffert Mean

    Directory of Open Access Journals (Sweden)

    Hui Sun

    2013-01-01

    Full Text Available We obtain sharp bounds for the Seiffert mean in terms of a two parameter family of means. Our results generalize and extend the recent bounds presented in the Journal of Inequalities and Applications (2012 and Abstract and Applied Analysis (2012.

  17. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  18. Detection of Differential Item Functioning Using the Lasso Approach

    Science.gov (United States)

    Magis, David; Tuerlinckx, Francis; De Boeck, Paul

    2015-01-01

    This article proposes a novel approach to detect differential item functioning (DIF) among dichotomously scored items. Unlike standard DIF methods that perform an item-by-item analysis, we propose the "LR lasso DIF method": logistic regression (LR) model is formulated for all item responses. The model contains item-specific intercepts,…

  19. Interval Estimations of the Two-Parameter Exponential Distribution

    Directory of Open Access Journals (Sweden)

    Lai Jiang

    2012-01-01

    Full Text Available In applied work, the two-parameter exponential distribution gives useful representations of many physical situations. Confidence interval for the scale parameter and predictive interval for a future independent observation have been studied by many, including Petropoulos (2011 and Lawless (1977, respectively. However, interval estimates for the threshold parameter have not been widely examined in statistical literature. The aim of this paper is to, first, obtain the exact significance function of the scale parameter by renormalizing the p∗-formula. Then the approximate Studentization method is applied to obtain the significance function of the threshold parameter. Finally, a predictive density function of the two-parameter exponential distribution is derived. A real-life data set is used to show the implementation of the method. Simulation studies are then carried out to illustrate the accuracy of the proposed methods.

  20. Two-parameter Levy processes along decreasing paths

    CERN Document Server

    Covo, Shai

    2010-01-01

    Let {X_{t_1,t_2}: t_1,t_2 >= 0} be a two-parameter L\\'evy process on R^d. We study basic properties of the one-parameter process {X_{x(t),y(t)}: t \\in T} where x and y are, respectively, nondecreasing and nonincreasing nonnegative continuous functions on the interval T. We focus on and characterize the case where the process has stationary increments.

  1. Beam Elements on Linear Variable Two-Parameter Elastic Foundation

    Directory of Open Access Journals (Sweden)

    Iancu-Bogdan Teodoru

    2008-01-01

    Full Text Available The traditional way to overcome the shortcomings of the Winkler foundation model is to incorporate spring coupling by assemblages of mechanical elements such as springs, flexural elements (beams in one-dimension, 1-D, plates in 2-D, shear-only layers and deformed, pretensioned membranes. This is the class of two-parameter foundations ? named like this because they have the second parameter which introduces interactions between adjacent springs, in addition to the first parameter from the ordinary Winkler?s model. This class of models includes Wieghardt, Filonenko-Borodich, Hetényi and Pasternak foundations. Mathematically, the equations to describe the reaction of the two-parameter foundations are equilibrium, and the only difference is the definition of the parameters. In order to analyse the bending behavior of a Euler-Bernoulli beam resting on linear variable two-parameter elastic foundation a (displacement Finite Element (FE formulation, based on the cubic displacement function of the governing differential equation, is introduced.

  2. Applicability of Item Response Theory to the Korean Nurses' Licensing Examination

    Directory of Open Access Journals (Sweden)

    Geum-Hee Jeong

    2005-06-01

    Full Text Available To test the applicability of item response theory (IRT to the Korean Nurses' Licensing Examination (KNLE, item analysis was performed after testing the unidimensionality and goodness-of-fit. The results were compared with those based on classical test theory. The results of the 330-item KNLE administered to 12,024 examinees in January 2004 were analyzed. Unidimensionality was tested using DETECT and the goodness-of-fit was tested using WINSTEPS for the Rasch model and Bilog-MG for the two-parameter logistic model. Item analysis and ability estimation were done using WINSTEPS. Using DETECT, Dmax ranged from 0.1 to 0.23 for each subject. The mean square value of the infit and outfit values of all items using WINSTEPS ranged from 0.1 to 1.5, except for one item in pediatric nursing, which scored 1.53. Of the 330 items, 218 (42.7% were misfit using the two-parameter logistic model of Bilog-MG. The correlation coefficients between the difficulty parameter using the Rasch model and the difficulty index from classical test theory ranged from 0.9039 to 0.9699. The correlation between the ability parameter using the Rasch model and the total score from classical test theory ranged from 0.9776 to 0.9984. Therefore, the results of the KNLE fit unidimensionality and goodness-of-fit for the Rasch model. The KNLE should be a good sample for analysis according to the IRT Rasch model, so further research using IRT is possible.

  3. Computational Logistics

    DEFF Research Database (Denmark)

    Pacino, Dario; Voss, Stefan; Jensen, Rune Møller

    2013-01-01

    This book constitutes the refereed proceedings of the 4th International Conference on Computational Logistics, ICCL 2013, held in Copenhagen, Denmark, in September 2013. The 19 papers presented in this volume were carefully reviewed and selected for inclusion in the book. They are organized...... in topical sections named: maritime shipping, road transport, vehicle routing problems, aviation applications, and logistics and supply chain management....

  4. Computational Logistics

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the 4th International Conference on Computational Logistics, ICCL 2013, held in Copenhagen, Denmark, in September 2013. The 19 papers presented in this volume were carefully reviewed and selected for inclusion in the book. They are organized...... in topical sections named: maritime shipping, road transport, vehicle routing problems, aviation applications, and logistics and supply chain management....

  5. Reverse logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); S.D.P. Flapper; R. Dekker (Rommert)

    2002-01-01

    textabstractThis paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In addi

  6. Fitting Ranked Linguistic Data with Two-Parameter Functions

    Directory of Open Access Journals (Sweden)

    Wentian Li

    2010-07-01

    Full Text Available It is well known that many ranked linguistic data can fit well with one-parameter models such as Zipf’s law for ranked word frequencies. However, in cases where discrepancies from the one-parameter model occur (these will come at the two extremes of the rank, it is natural to use one more parameter in the fitting model. In this paper, we compare several two-parameter models, including Beta function, Yule function, Weibull function—all can be framed as a multiple regression in the logarithmic scale—in their fitting performance of several ranked linguistic data, such as letter frequencies, word-spacings, and word frequencies. We observed that Beta function fits the ranked letter frequency the best, Yule function fits the ranked word-spacing distribution the best, and Altmann, Beta, Yule functions all slightly outperform the Zipf’s power-law function in word ranked- frequency distribution.

  7. ltm: An R Package for Latent Variable Modeling and Item Response Analysis

    Directory of Open Access Journals (Sweden)

    Dimitris Rizopoulos

    2006-11-01

    Full Text Available The R package ltm has been developed for the analysis of multivariate dichotomous and polytomous data using latent variable models, under the Item Response Theory approach. For dichotomous data the Rasch, the Two-Parameter Logistic, and Birnbaum's Three-Parameter models have been implemented, whereas for polytomous data Semejima's Graded Response model is available. Parameter estimates are obtained under marginal maximum likelihood using the Gauss-Hermite quadrature rule. The capabilities and features of the package are illustrated using two real data examples.

  8. Logistical Worlds

    Directory of Open Access Journals (Sweden)

    Ned Rossiter

    2014-03-01

    Full Text Available As the managerial art and science of coordinating the movement of people, finance and things, logistical operations are central to contemporary capital. Despite its materiality in the form of communications and transport infrastructure, logistics remains an abstract machine for many. This is largely due to the compartmental structure of global supply chains and the invisibility of code. In registering the mediating force of logistics, the essay considers parametric politics as an architecture of intervention for both game design and software development. There are implications here not only for gameplay, but also the invention of method and governance of labour. How, for instance, might game design facilitate the production of a political knowledge of logistics? This becomes a matter to address for labour power vis-à-vis collective research on infrastructure, software and global supply chains.

  9. Use of Robust z in Detecting Unstable Items in Item Response Theory Models

    Science.gov (United States)

    Huynh, Huynh; Meyer, Patrick

    2010-01-01

    The first part of this paper describes the use of the robust z[subscript R] statistic to link test forms using the Rasch (or one-parameter logistic) model. The procedure is then extended to the two-parameter and three-parameter logistic and two-parameter partial credit (2PPC) models. A real set of data was used to illustrate the extension. The…

  10. Two-parameter asymptotics in magnetic Weyl calculus

    Science.gov (United States)

    Lein, Max

    2010-12-01

    This paper is concerned with small parameter asymptotics of magnetic quantum systems. In addition to a semiclassical parameter ɛ, the case of small coupling λ to the magnetic vector potential naturally occurs in this context. Magnetic Weyl calculus is adapted to incorporate both parameters, at least one of which needs to be small. Of particular interest is the expansion of the Weyl product which can be used to expand the product of operators in a small parameter, a technique which is prominent to obtain perturbation expansions. Three asymptotic expansions for the magnetic Weyl product of two Hörmander class symbols are proven as (i) ɛ ≪ 1 and λ ≪ 1, (ii) ɛ ≪ 1 and λ = 1, as well as (iii) ɛ = 1 and λ ≪ 1. Expansions (i) and (iii) are impossible to obtain with ordinary Weyl calculus. Furthermore, I relate the results derived by ordinary Weyl calculus with those obtained with magnetic Weyl calculus by one- and two-parameter expansions. To show the power and versatility of magnetic Weyl calculus, I derive the semirelativistic Pauli equation as a scaling limit from the Dirac equation up to errors of fourth order in 1/c.

  11. Cosmology on all scales: a two-parameter perturbation expansion

    CERN Document Server

    Goldberg, Sophia R; Malik, Karim A

    2016-01-01

    We propose and construct a two-parameter perturbative expansion around a Friedmann-Lema\\^{i}tre-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of non-linear structure. This framework reduces to the weak-field and slow-motion post-Newtonian treatment of gravity in the appropriate limits, but also includes the low-amplitude large-scale fluctuations that are important for cosmological modelling. We derive a set of field equations that can be applied to the late Universe, where non-linear structure exists on supercluster scales, and perform a detailed investigation of the associated gauge problem. This allows us to identify a consistent set of perturbed quantities in both the gravitational and matter sectors, and to construct a set of gauge-invariant quantities that correspond to each of them. The field equations, written in terms of these quantities, take on a relatively simple form, and allow the effects of small-scale structure on the large-scale properties...

  12. Mirror symmetry for two-parameter models, 1

    CERN Document Server

    Candelas, Philip; Font, A; Katz, S; Morrison, Douglas Robert Ogston; Candelas, Philip; Ossa, Xenia de la; Font, Anamaria; Katz, Sheldon; Morrison, David R.

    1994-01-01

    We study, by means of mirror symmetry, the quantum geometry of the K\\"ahler-class parameters of a number of Calabi-Yau manifolds that have $b_{11}=2$. Our main interest lies in the structure of the moduli space and in the loci corresponding to singular models. This structure is considerably richer when there are two parameters than in the various one-parameter models that have been studied hitherto. We describe the intrinsic structure of the point in the (compactification of the) moduli space that corresponds to the large complex structure or classical limit. The instanton expansions are of interest owing to the fact that some of the instantons belong to families with continuous parameters. We compute the Yukawa couplings and their expansions in terms of instantons of genus zero. By making use of recent results of Bershadsky et al. we compute also the instanton numbers for instantons of genus one. For particular values of the parameters the models become birational to certain models with one parameter. The co...

  13. Logistic regression.

    Science.gov (United States)

    Nick, Todd G; Campbell, Kathleen M

    2007-01-01

    The Medical Subject Headings (MeSH) thesaurus used by the National Library of Medicine defines logistic regression models as "statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable." Logistic regression models are used to study effects of predictor variables on categorical outcomes and normally the outcome is binary, such as presence or absence of disease (e.g., non-Hodgkin's lymphoma), in which case the model is called a binary logistic model. When there are multiple predictors (e.g., risk factors and treatments) the model is referred to as a multiple or multivariable logistic regression model and is one of the most frequently used statistical model in medical journals. In this chapter, we examine both simple and multiple binary logistic regression models and present related issues, including interaction, categorical predictor variables, continuous predictor variables, and goodness of fit.

  14. Slowness logistics

    OpenAIRE

    Paché, Gilles

    2007-01-01

    Abstract Works conducted in logistics management mostly emphasize the importance of a `time compression' strategy to develop a sustainable competitive advantage. At the level of the design, manufacturing or distribution of products to consumers, high-speed orientation is now considered to be a universal source of performance. Drawing from current developments in the French food retailing industry, the paper...

  15. PENGEMBANGAN TES BERPIKIR KRITIS DENGAN PENDEKATAN ITEM RESPONSE THEORY

    Directory of Open Access Journals (Sweden)

    Fajrianthi Fajrianthi

    2016-06-01

    Assumption, Deduction, Interpretation dan Evaluation of arguments. 1453 respondents from Surabaya, Gresik, Tuban, Bojonegoro and Rembang were used for trailing the test. The dichotomous data were analized using the Item Response Theory with two parameter logistic model using statistical program Mplus ver. 6.11. Several assumptions were tested prior the IRT analysis; the test of unidimensionality, local independency and Item Characteristic Curve (ICC. Amongst 68 items only 15 items had good discrimination parameter. Difficulty item level ranged from – 4.95 to 2.448. The study was limited in producing high number of qualified items due to its failure in finding subject matter experts in critical thinking area and inadequate choice in scoring method. Keywords: test development, critical thinking, Item response theory

  16. AN ITEM RESPONSE MODEL WITH SINGLE PEAKED ITEM CHARACTERISTIC CURVES - THE PARELLA MODEL

    NARCIS (Netherlands)

    HOIJTINK, H; MOLENAAR, [No Value

    In this paper an item response model (the PARELLA model) designed specifically for the measurement of attitudes and preferences will be introduced. In contrast with the item response models currently used (e.g. the Rasch model and, the two and three parameter logistic model) the item characteristic

  17. The 18 Household Food Security Survey items provide valid food security classifications for adults and children in the Caribbean

    Directory of Open Access Journals (Sweden)

    Nunes Cheryl

    2006-02-01

    Full Text Available Abstract Background We tested the properties of the 18 Household Food Security Survey (HFSS items, and the validity of the resulting food security classifications, in an English-speaking middle-income country. Methods Survey of primary school children in Trinidad and Tobago. Parents completed the HFSS. Responses were analysed for the 10 adult-referenced items and the eight child-referenced items. Item response theory models were fitted. Item calibrations and subject scores from a one-parameter logistic (1PL model were compared with those from either two-parameter logistic model (2PL or a model for differential item functioning (DIF by ethnicity. Results There were 5219 eligible with 3858 (74% completing at least one food security item. Adult item calibrations (standard error in the 1PL model ranged from -4.082 (0.019 for the 'worried food would run out' item to 3.023 (0.042 for 'adults often do not eat for a whole day'. Child item calibrations ranged from -3.715 (0.025 for 'relied on a few kinds of low cost food' to 3.088 (0.039 for 'child didn't eat for a whole day'. Fitting either a 2PL model, which allowed discrimination parameters to vary between items, or a differential item functioning model, which allowed item calibrations to vary between ethnic groups, had little influence on interpretation. The classification based on the adult-referenced items showed that there were 19% of respondents who were food insecure without hunger, 10% food insecure with moderate hunger and 6% food insecure with severe hunger. The classification based on the child-referenced items showed that there were 23% of children who were food insecure without hunger and 9% food insecure with hunger. In both children and adults food insecurity showed a strong, graded association with lower monthly household income (P Conclusion These results support the use of 18 HFSS items to classify food security status of adults or children in an English-speaking country where food

  18. Logistics Reduction Technologies for Exploration Missions

    Science.gov (United States)

    Broyan, James L., Jr.; Ewert, Michael K.; Fink, Patrick W.

    2014-01-01

    Human exploration missions under study are limited by the launch mass capacity of existing and planned launch vehicles. The logistical mass of crew items is typically considered separate from the vehicle structure, habitat outfitting, and life support systems. Although mass is typically the focus of exploration missions, due to its strong impact on launch vehicle and habitable volume for the crew, logistics volume also needs to be considered. NASA's Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) Project is developing six logistics technologies guided by a systems engineering cradle-to-grave approach to enable after-use crew items to augment vehicle systems. Specifically, AES LRR is investigating the direct reduction of clothing mass, the repurposing of logistical packaging, the use of autonomous logistics management technologies, the processing of spent crew items to benefit radiation shielding and water recovery, and the conversion of trash to propulsion gases. Reduction of mass has a corresponding and significant impact to logistical volume. The reduction of logistical volume can reduce the overall pressurized vehicle mass directly, or indirectly benefit the mission by allowing for an increase in habitable volume during the mission. The systematic implementation of these types of technologies will increase launch mass efficiency by enabling items to be used for secondary purposes and improve the habitability of the vehicle as mission durations increase. Early studies have shown that the use of advanced logistics technologies can save approximately 20 m(sup 3) of volume during transit alone for a six-person Mars conjunction class mission.

  19. Unification of the Two-Parameter Equation of State and the Principle of Corresponding States

    DEFF Research Database (Denmark)

    Mollerup, Jørgen

    1998-01-01

    A two-parameter equation of state is a two-parameter corresponding states model. A two-parameter corresponding states model is composed of two scale factor correlations and a reference fluid equation of state. In a two-parameter equation of state the reference equation of state is the two......-parameter equation of state itself. If we retain the scale factor correlations derived from a two-parameter equation of state, but replace the two-parameter equation of state with a more accurate pure component equation of state for the reference fluid, we can improve the existing models of equilibrium properties...... without refitting any model parameters, and without imposing other restrictions as regards to species and mixing rules as already imposed by the two-parameter equation of state. The theory and procedure is outlined in the paper....

  20. Underground logistics

    CERN Document Server

    Foraz, K; CERN. Geneva. TS Department

    2005-01-01

    More than 80’000 tons of materials have to be transported and installed down into the LHC tunnel. The magnet assemblies which represent about 50’000 tons, will be transported according to the master schedule between March 2005 and November 2006. Considering that these about 1’800 cryo-magnets will be transported at a maximum speed of 3 km/h in a narrow tube (where installation works and hardware commissioning activities are ongoing) this duration of 21 months is a real challenge. This paper aims at describing: - the information flows between the different people involved in the logistics attached to the cryo-magnets, - the organization chosen within the Installation Coordination group, - the problems encountered so far and the solutions adopted. The coordination process with other underground transport and activities, mainly for the QRL will also be presented.

  1. Item nonresponse in questionnaire research with children

    NARCIS (Netherlands)

    Hox, J.J.; Borgers, N.

    2001-01-01

    This study investigates the effect of item and person characteristics on item nonresponse, for written questionnaires used with school children. Secondary analyses were done on questionnaire data collected in five distinct studies. To analyze the data, logistic multilevel analysis was used with the

  2. REVERSE LOGISTICS RETAIL LEVEL RETURN

    Directory of Open Access Journals (Sweden)

    Ivona Bajor

    2014-06-01

    Full Text Available Conducting scientific research regarding reverse logistics systems includes certain difficulties. Developed logistics systems are aimed at analysing reverse logistics issues and tend to continuously detect differences and oscillations in the flow of returned products and their characteristics. Developing logistics systems, as Croatian, find reverse logistics issues, regarding product returns, significantly complex and very often these issues are not observed as issues of priority. As distributive flow, reverse logistics systems fundaments should be also based on detailed analysis. Analysis in this flow presents amounts, reasons, process flows and quality of returned items. Because of complex product evaluation on individual level, reverse logistics procedures should be implemented as a methodology individually developed for every supply chain subject. This paper presents a research of retail level returns on the Croatian market, where the analysis implicated that the majority of products in return for this level is directed from final consumers and presents noncurrent inventories of distribution chain. The paper will present conducted research regarding characteristics of returns and routing these products from the retail level.

  3. Virtual Market Using Logistics Optimization

    Directory of Open Access Journals (Sweden)

    Reddy Veera Babu

    2010-03-01

    Full Text Available In this paper we have proposed an idea called virtual marketplace that effectively utilizes the widespread and vast cellular phone infrastructure and the recent advances in sensor technology, leading to tremendous cost and time saving. This idea takes virtual markets to a new level of evolution, with unparalleled customer convenience, speed, quality assurance and reliability. Almost every item such as books, electronic goods, milk, vegetables, televisions and food items can be traded using this virtual market. Some of the key features are: (i Wireless communication-enabled real-time inventory and (ii logistics optimization (iii quality control (iv delivery people-human employees to pick up and deliver products and (v real time authentication of transactions. The goal of this work is to develop an eco-friendly virtual market for potential buyers/sellers (such as enabling trade with in sustainable or ecological communities, providing an efficient client-server communication through Logistics optimization.

  4. Use of Robust z in Detecting Unstable Items in Item Response Theory Models

    Directory of Open Access Journals (Sweden)

    Huynh Huynh

    2010-01-01

    Full Text Available The first part of this paper describes the use of the robust zR statistic to link test forms using the Rasch (or one-parameter logistic model. The procedure is then extended to the two-parameter and three-parameter logistic and two-parameter partial credit (2PPC models. A real set of data was used to illustrate the extension. The linking results illustrate the efficacy of the robust zR vis- -vis some of the most commonly used processes such as the Stocking and Lord (1983 linking process.

  5. Semiparametric Item Response Functions in the Context of Guessing

    Science.gov (United States)

    Falk, Carl F.; Cai, Li

    2016-01-01

    We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood-based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally…

  6. Asymptotic Results for the Two-parameter Poisson-Dirichlet Distribution

    CERN Document Server

    Feng, Shui

    2009-01-01

    The two-parameter Poisson-Dirichlet distribution is the law of a sequence of decreasing nonnegative random variables with total sum one. It can be constructed from stable and Gamma subordinators with the two-parameters, $\\alpha$ and $\\theta$, corresponding to the stable component and Gamma component respectively. The moderate deviation principles are established for the two-parameter Poisson-Dirichlet distribution and the corresponding homozygosity when $\\theta$ approaches infinity, and the large deviation principle is established for the two-parameter Poisson-Dirichlet distribution when both $\\alpha$ and $\\theta$ approach zero.

  7. Applications of the Linear Logistic Test Model in Psychometric Research

    Science.gov (United States)

    Kubinger, Klaus D.

    2009-01-01

    The linear logistic test model (LLTM) breaks down the item parameter of the Rasch model as a linear combination of some hypothesized elementary parameters. Although the original purpose of applying the LLTM was primarily to generate test items with specified item difficulty, there are still many other potential applications, which may be of use…

  8. The diagnostic utility of separation anxiety disorder symptoms: an item response theory analysis.

    Science.gov (United States)

    Cooper-Vince, Christine E; Emmert-Aronson, Benjamin O; Pincus, Donna B; Comer, Jonathan S

    2014-01-01

    At present, it is not clear whether the current definition of separation anxiety disorder (SAD) is the optimal classification of developmentally inappropriate, severe, and interfering separation anxiety in youth. Much remains to be learned about the relative contributions of individual SAD symptoms for informing diagnosis. Two-parameter logistic Item Response Theory analyses were conducted on the eight core SAD symptoms in an outpatient anxiety sample of treatment-seeking children (N = 359, 59.3 % female, M Age = 11.2) and their parents to determine the diagnostic utility of each of these symptoms. Analyses considered values of item threshold, which characterize the SAD severity level at which each symptom has a 50 % chance of being endorsed, and item discrimination, which characterize how well each symptom distinguishes individuals with higher and lower levels of SAD. Distress related to separation and fear of being alone without major attachment figures showed the strongest discrimination properties and the lowest thresholds for being endorsed. In contrast, worry about harm befalling attachment figures showed the poorest discrimination properties, and nightmares about separation showed the highest threshold for being endorsed. Distress related to separation demonstrated crossing differential item functioning associated with age-at lower separation anxiety levels excessive fear at separation was more likely to be endorsed for children ≥9 years, whereas at higher levels this symptom was more likely to be endorsed by children <9 years. Implications are discussed for optimizing the taxonomy of SAD in youth.

  9. Evaluating Item Discrimination Power of WHOQOL-BREF from an Item Response Model Perspectives

    Science.gov (United States)

    Lin, Ting Hsiang; Yao, Grace

    2009-01-01

    Quality of life (QOL) has become an important component of health. By using the methodology of psychometric theory, we examine the item properties of the WHOQOL-BRIEF. Samejima's graded response model with natural metrics of the logistic response function was fitted. The results showed items with negative natures were less discriminating. Items…

  10. Logistics Management Information System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The logistics information is the logistics manageme nt 's inevitable request. The paper introduces several kinds of logistics informat ion system and their functions in the logistics management, such as the warehous e management system (WMS) in the delivery center, the control system for transpo rtation and delivery, the supply chain management (SCM), the optimization of th e logistics system, etc. In the author's opinion, the development of logistics could been divided into four phases. And the logistic...

  11. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  12. Two-parameter deformed supersymmetric oscillators with SUq1/q2(n|m)-covariance

    CERN Document Server

    Algin, A; Arikan, A S; Algin, Abdullah; Arik, Metin; Arikan, Ali Serdar

    2003-01-01

    A two-parameter deformed superoscillator system with SUq1/q2(n|m)-covariance is presented and used to construct a two-parameter deformed N=2 SUSY algebra. The Fock space representation of the algebra is discussed and the deformed Hamiltonian for such generalized superoscillators is obtained.

  13. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  14. Analysis of Logistics Costs of the Ukrainian Semiconductor Industry

    OpenAIRE

    Popova Viktoriya D.

    2014-01-01

    The goal of the article is analysis of logistics costs in production of semiconductor materials using example of two Ukrainian enterprises. The article studies influence of logistics management and logistics costs upon formation of the final cost value (price) of a commodity (service). It gives an assessment of logistics costs of Ukrainian semiconductor enterprises and establishes its structure by types of main expenditure items: material, transport, production and storehouse. It establishes ...

  15. Complex logistics audit system

    Directory of Open Access Journals (Sweden)

    Zuzana Marková

    2010-02-01

    Full Text Available Complex logistics audit system is a tool for realization of logistical audit in the company. The current methods for logistics auditare based on “ad hok” analysis of logisticsl system. This paper describes system for complex logistics audit. It is a global diagnosticsof logistics processes and functions of enterprise. The goal of logistics audit is to provide comparative documentation for managementabout state of logistics in company and to show the potential of logistics changes in order to achieve more effective companyperformance.

  16. Secondary Item Procurement Lead Time Study.

    Science.gov (United States)

    1984-03-01

    NONEhhhhhh % I - 15 III& 1-- -NAION&°I° oI Ai OF .° NAIU REUONF TEST CANA -~~ 7 .. SECONDARY ITEM PROCUREMENT LEAD TIME STUDY __ LOGISTICS SYSTEMS...ASSISTANT SECRETARY OF THE AIR FORCE (RD&L) DIRECTOR, DEFENSE LOGISTICS AGENCY SUBJECT: Secondary Item Procurement Lead Time Study A recent report by the...determination of procurement lead time. A plan for the study is enclosed. In order to achieve the objectives of the procurement lead time study as well as the

  17. A Review of Test Item Types

    Science.gov (United States)

    2008-03-06

    for integration with the CAT- ASVAB as it exists now. The CAT-ASVAB currently employs only dichotomously scored items using the 3 parameter logistic ...model ( 3PL ; Lord & Novick, 1968). IRT models appropriate for polytomously scored items (e.g., Muraki, 1997) are available, and mixing of models is not...problematic within the IRT framework per se. Nevertheless, the current CAT-ASVAB infrastructure is configured to work with the 3PL model only, and

  18. QUASI-DIAGONALIZATION FOR A SINGULARLY PERTURBED DIFFERENTIAL SYSTEM WITH TWO PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    By two successive linear transformations,a singularly perturbed differential system with two parameters is quasi-diagonalized. The method of variation of constants and the principle of contraction map are used to prove the existence of the transformations.

  19. Quasi-sure Product Variation of Two-parameter Smooth Martingales on the Wiener Space

    Institute of Scientific and Technical Information of China (English)

    Ji Cheng LIU; Jia Gang REN

    2006-01-01

    In this paper, we prove that the process of product variation of a two-parameter smooth martingale admits an ∞ modification, which can be constructed as the quasi-sure limit of sum of the corresponding product variation.

  20. Two-parameter semigroups, evolutions and their applications to Markov and diffusion fields on the plane

    Directory of Open Access Journals (Sweden)

    Yu. Mishura

    1996-01-01

    Full Text Available We study two-parameter coordinate-wise C0-semigroups and their generators, as well as two-parameter evolutions and differential equations up to the second order for them. These results are applied to obtain the Hille-Yosida theorem for homogeneous Markov fields of the Feller type and to establish forward, backward, and mixed Kolmogorov equations for nonhomogeneous diffusion fields on the plane.

  1. Linear Logistic Test Modeling with R

    Directory of Open Access Journals (Sweden)

    Purya Baghaei

    2014-01-01

    Full Text Available The present paper gives a general introduction to the linear logistic test model (Fischer, 1973, an extension of the Rasch model with linear constraints on item parameters, along with eRm (an R package to estimate different types of Rasch models; Mair, Hatzinger, & Mair, 2014 functions to estimate the model and interpret its parameters. The applications of the model in test validation, hypothesis testing, cross-cultural studies of test bias, rule-based item generation, and investigating construct irrelevant factors which contribute to item difficulty are explained. The model is applied to an English as a foreign language reading comprehension test and the results are discussed.

  2. Logistic chain modelling

    NARCIS (Netherlands)

    Slats, P.A.; Bhola, B.; Evers, J.J.M.; Dijkhuizen, G.

    1995-01-01

    Logistic chain modelling is very important in improving the overall performance of the total logistic chain. Logistic models provide support for a large range of applications, such as analysing bottlenecks, improving customer service, configuring new logistic chains and adapting existing chains to n

  3. Exploration Mission Benefits From Logistics Reduction Technologies

    Science.gov (United States)

    Broyan, James Lee, Jr.; Schlesinger, Thilini; Ewert, Michael K.

    2016-01-01

    Technologies that reduce logistical mass, volume, and the crew time dedicated to logistics management become more important as exploration missions extend further from the Earth. Even modest reductions in logical mass can have a significant impact because it also reduces the packing burden. NASA's Advanced Exploration Systems' Logistics Reduction Project is developing technologies that can directly reduce the mass and volume of crew clothing and metabolic waste collection. Also, cargo bags have been developed that can be reconfigured for crew outfitting and trash processing technologies to increase habitable volume and improve protection against solar storm events are under development. Additionally, Mars class missions are sufficiently distant that even logistics management without resupply can be problematic due to the communication time delay with Earth. Although exploration vehicles are launched with all consumables and logistics in a defined configuration, the configuration continually changes as the mission progresses. Traditionally significant ground and crew time has been required to understand the evolving configuration and locate misplaced items. For key mission events and unplanned contingencies, the crew will not be able to rely on the ground for logistics localization assistance. NASA has been developing a radio frequency identification autonomous logistics management system to reduce crew time for general inventory and enable greater crew self-response to unplanned events when a wide range of items may need to be located in a very short time period. This paper provides a status of the technologies being developed and there mission benefits for exploration missions.

  4. The Automated Logistics Element Planning System (ALEPS)

    Science.gov (United States)

    Schwaab, Douglas G.

    1992-01-01

    ALEPS, which is being developed to provide the SSF program with a computer system to automate logistics resupply/return cargo load planning and verification, is presented. ALEPS will make it possible to simultaneously optimize both the resupply flight load plan and the return flight reload plan for any of the logistics carriers. In the verification mode ALEPS will support the carrier's flight readiness reviews and control proper execution of the approved plans. It will also support the SSF inventory management system by providing electronic block updates to the inventory database on the cargo arriving at or departing the station aboard a logistics carrier. A prototype drawer packing algorithm is described which is capable of generating solutions for 3D packing of cargo items into a logistics carrier storage accommodation. It is concluded that ALEPS will provide the capability to generate and modify optimized loading plans for the logistics elements fleet.

  5. The Automated Logistics Element Planning System (ALEPS)

    Science.gov (United States)

    Schwaab, Douglas G.

    1992-01-01

    ALEPS, which is being developed to provide the SSF program with a computer system to automate logistics resupply/return cargo load planning and verification, is presented. ALEPS will make it possible to simultaneously optimize both the resupply flight load plan and the return flight reload plan for any of the logistics carriers. In the verification mode ALEPS will support the carrier's flight readiness reviews and control proper execution of the approved plans. It will also support the SSF inventory management system by providing electronic block updates to the inventory database on the cargo arriving at or departing the station aboard a logistics carrier. A prototype drawer packing algorithm is described which is capable of generating solutions for 3D packing of cargo items into a logistics carrier storage accommodation. It is concluded that ALEPS will provide the capability to generate and modify optimized loading plans for the logistics elements fleet.

  6. Logistics and Exports

    OpenAIRE

    2008-01-01

    Drawing on a new and comprehensive measure of logistics quality, our gravity model suggests logistics in the exporting and partner-country can have an important impact on bilateral exports. A one standard deviation improvement in the exporter’s logistics quality, which for example would improve Gabon to the level of Guinea, would raise exports by almost 60%. Landlocked countries’ exports depend on their neighbours’ logistics, but their own logistics quality is not as important as for other co...

  7. Shipping lines and logistics

    OpenAIRE

    FREMONT, A

    2006-01-01

    For some time it has been acknowledged that logistics is a driving force that shapes the integration of the transport chain. This paper argues that while the liner shipping industry exhibits increased horizontal integration, its vertical integration remains limited. A clear distinction is drawn between freight logistics, container logistics and vessel logistics. Freight logistics is defined as part of the supply chain process, the focus of which are the goods being transported. The purpose of...

  8. Location and logistics

    OpenAIRE

    Alumura, Sibel A.; Karab, Bahar Y.; Melo, M. Teresa

    2013-01-01

    Facility location decisions play a critical role in designing logistics networks. This article provides some guidelines on how location decisions and logistics functions can be integrated into a single mathematical model to optimize the configuration of a logistics network. This will be illustrated by two generic models, one supporting the design of a forward logistics network and the other addressing the specific requirements of a reverse logistics network. Several special cases and extensio...

  9. Location and logistics

    OpenAIRE

    Alumura, Sibel A.; Karab, Bahar Y.; Melo, M. Teresa

    2013-01-01

    Facility location decisions play a critical role in designing logistics networks. This article provides some guidelines on how location decisions and logistics functions can be integrated into a single mathematical model to optimize the configuration of a logistics network. This will be illustrated by two generic models, one supporting the design of a forward logistics network and the other addressing the specific requirements of a reverse logistics network. Several special cases and extensio...

  10. Linear Logistic Test Modeling with R

    Science.gov (United States)

    Baghaei, Purya; Kubinger, Klaus D.

    2015-01-01

    The present paper gives a general introduction to the linear logistic test model (Fischer, 1973), an extension of the Rasch model with linear constraints on item parameters, along with eRm (an R package to estimate different types of Rasch models; Mair, Hatzinger, & Mair, 2014) functions to estimate the model and interpret its parameters. The…

  11. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  12. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse log

  13. Theory of two-parameter Markov chain with an application in warranty study

    CERN Document Server

    Calvache, Álvaro

    2012-01-01

    In this paper we present the classical results of Kolmogorov's backward and forward equations to the case of a two-parameter Markov process. These equations relates the infinitesimal transition matrix of the two-parameter Markov process. However, solving these equations is not possible and we require a numerical procedure. In this paper, we give an alternative method by use of double Laplace transform of the transition probability matrix and of the infinitesimal transition matrix of the process. An illustrative example is presented for the method proposed. In this example, we consider a two-parameter warranty model, in which a system can be any of these states: working, failure. We calculate the transition density matrix of these states and also the cost of the warranty for the proposed model.

  14. On the Usefulness of a Multilevel Logistic Regression Approach to Person-Fit Analysis

    Science.gov (United States)

    Conijn, Judith M.; Emons, Wilco H. M.; van Assen, Marcel A. L. M.; Sijtsma, Klaas

    2011-01-01

    The logistic person response function (PRF) models the probability of a correct response as a function of the item locations. Reise (2000) proposed to use the slope parameter of the logistic PRF as a person-fit measure. He reformulated the logistic PRF model as a multilevel logistic regression model and estimated the PRF parameters from this…

  15. On the Usefulness of a Multilevel Logistic Regression Approach to Person-Fit Analysis

    Science.gov (United States)

    Conijn, Judith M.; Emons, Wilco H. M.; van Assen, Marcel A. L. M.; Sijtsma, Klaas

    2011-01-01

    The logistic person response function (PRF) models the probability of a correct response as a function of the item locations. Reise (2000) proposed to use the slope parameter of the logistic PRF as a person-fit measure. He reformulated the logistic PRF model as a multilevel logistic regression model and estimated the PRF parameters from this…

  16. Screening Test Items for Differential Item Functioning

    Science.gov (United States)

    Longford, Nicholas T.

    2014-01-01

    A method for medical screening is adapted to differential item functioning (DIF). Its essential elements are explicit declarations of the level of DIF that is acceptable and of the loss function that quantifies the consequences of the two kinds of inappropriate classification of an item. Instead of a single level and a single function, sets of…

  17. IRT Item Parameters and the Reliability and Validity of Pretest, Posttest, and Gain Scores

    Science.gov (United States)

    May, Kim; Jackson, Tameika S.

    2005-01-01

    The effect of different combinations of item response theory (IRT) item parameters (item difficulty, item discrimination, and the guessing probability) on the reliability and construct validity (correlation with the latent trait being measured) of pretest, posttest, and gain scores was analytically examined using the 3-parameter logistic (3PL)…

  18. A Simulation Study of Methods for Assessing Differential Item Functioning in Computer-Adaptive Tests.

    Science.gov (United States)

    Zwick, Rebecca; And Others

    Simulated data were used to investigate the performance of modified versions of the Mantel-Haenszel and standardization methods of differential item functioning (DIF) analysis in computer-adaptive tests (CATs). Each "examinee" received 25 items out of a 75-item pool. A three-parameter logistic item response model was assumed, and…

  19. SIMULATION OF LOGISTICS PROCESSES

    OpenAIRE

    Yu. Taranenko; Fedorenko, I.

    2016-01-01

    The article deals with the theoretical basis of the simulation. The study shows the simulation of logistic processes in industrial countries is an integral part of many economic projects aimed at the creation or improvement of logistics systems. The paper was used model Beer Game for management of logistics processes in the enterprise. The simulation model implements in AnyLogic package. AnyLogic product allows us to consider the logistics processes as an integrated system, which allows reach...

  20. Reverse logistics - a framework

    OpenAIRE

    Brito, Marisa; Dekker, Rommert

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of products, processes and actors. In addition we provide a decision framework for Reverse Logistics and we present it according to long, medium and short term decisions, i.e. strategic-tactic-operational decis...

  1. Operationa1 Logistics 2010.

    Science.gov (United States)

    2007-11-02

    Joint Vision 2010 and Focused Logistics as the start point to describe how military logistics might look in 2010. Although changes are occurring at...Although many initiatives are currently underway which will transform military logistics , this paper attempts to tie the many emerging concepts and

  2. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of product

  3. A Jacobi-Davidson type method for a right definite two-parameter eigenvalue problem

    NARCIS (Netherlands)

    Hochstenbach, M.; Plestenjak, B.

    2001-01-01

    We present a new numerical iterative method for computing selected eigenpairs of a right definite two-parameter eigenvalue problem. The method works even without good initial approximations and is able to tackle large problems that are too expensive for existing methods. The new method is similar

  4. On modeling of lifetime data using two-parameter Gamma and Weibull distributions

    NARCIS (Netherlands)

    Shanker, Rama; Shukla, Kamlesh Kumar; Shanker, Ravi; Leonida, Tekie Asehun

    2016-01-01

    The analysis and modeling of lifetime data are crucial in almost all applied sciences including medicine, insurance, engineering, behavioral sciences and finance, amongst others. The main objective of this paper is to have a comparative study of two-parameter gamma and Weibull distributions for mode

  5. Codimension-Two Bifurcation Analysis in Hindmarsh-Rose Model with Two Parameters

    Institute of Scientific and Technical Information of China (English)

    DUAN Li-Xia; LU Qi-Shao

    2005-01-01

    @@ Bifurcation phenomena in a Hindmarsh-Rose neuron model are investigated. Special attention is paid to the bifurcation structures off two parameters, where codimension-two generalized-Hopf bifurcation and fold-Hopf bifurcation occur. The classification offiring patterns as well as the transition mechanism in different regions on the parameter plane are obtained.

  6. EQUIDISTANT TOOTH GENERATION ON NONCYLINDRICAL SURFACES FOR TWO-PARAMETER GEARING

    Directory of Open Access Journals (Sweden)

    Yuriy GUTSALENKO,

    2011-11-01

    Full Text Available The questions of design research of noncylindrical tooth surfaces for two-parameter gearing on example of bevel gears with constant normal pitch forgearing variators are been considered. Engineering is based on the special applied development of the mathematical theory of multiparametric mappings of space.

  7. SINGULARLY PERTURBED SOLUTION FOR THIRD ORDER NONLINEAR EQUATIONS WITH TWO PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A class of singularly perturbed boundary value problems for nonlinear equation of the third order with two parameters is considered. Under suitable conditions, using the theory of differential inequalities the existence and asymptotic behavior of the solution for boundary value problem are studied.

  8. Application of a two-parameter quantum algebra to rotational spectroscopy of nuclei

    Science.gov (United States)

    Barbier, R.; Kibler, M.

    1996-10-01

    A two-parameter quantum algebra Uqp( u2) is briefly investigated in this paper. The basic ingredients of a model based on the Uqp( u2) symmetry, the qp-rotator model, are presented in detail. Some general tendencies arising from the application of this model to the description of rotational bands of various atomic nuclei are summarized.

  9. Asymptotic Properties of Induced Maximum Likelihood Estimates of Nonlinear Models for Item Response Variables: The Finite-Generic-Item-Pool Case.

    Science.gov (United States)

    Jones, Douglas H.

    The progress of modern mental test theory depends very much on the techniques of maximum likelihood estimation, and many popular applications make use of likelihoods induced by logistic item response models. While, in reality, item responses are nonreplicate within a single examinee and the logistic models are only ideal, practitioners make…

  10. KSC ISS Logistics Support

    Science.gov (United States)

    Tellado, Joseph

    2014-01-01

    The presentation contains a status of KSC ISS Logistics Operations. It basically presents current top level ISS Logistics tasks being conducted at KSC, current International Partner activities, hardware processing flow focussing on late Stow operations, list of KSC Logistics POC's, and a backup list of Logistics launch site services. This presentation is being given at the annual International Space Station (ISS) Multi-lateral Logistics Maintenance Control Panel meeting to be held in Turin, Italy during the week of May 13-16. The presentatiuon content doesn't contain any potential lessons learned.

  11. Total Logistic Plant Solutions

    Directory of Open Access Journals (Sweden)

    Dusan Dorcak

    2016-02-01

    Full Text Available The Total Logistics Plant Solutions, plant logistics system - TLPS, based on the philosophy of advanced control processes enables complex coordination of business processes and flows and the management and scheduling of production in the appropriate production plans and planning periods. Main attributes of TLPS is to create a comprehensive, multi-level, enterprise logistics information system, with a certain degree of intelligence, which accepts the latest science and research results in the field of production technology and logistics. Logistic model of company understands as a system of mutually transforming flows of materials, energy, information, finance, which is realized by chain activities and operations

  12. Mission Benefits Analysis of Logistics Reduction Technologies

    Science.gov (United States)

    Ewert, Michael K.; Broyan, James Lee, Jr.

    2013-01-01

    Future space exploration missions will need to use less logistical supplies if humans are to live for longer periods away from our home planet. Anything that can be done to reduce initial mass and volume of supplies or reuse or recycle items that have been launched will be very valuable. Reuse and recycling also reduce the trash burden and associated nuisances, such as smell, but require good systems engineering and operations integration to reap the greatest benefits. A systems analysis was conducted to quantify the mass and volume savings of four different technologies currently under development by NASA s Advanced Exploration Systems (AES) Logistics Reduction and Repurposing project. Advanced clothing systems lead to savings by direct mass reduction and increased wear duration. Reuse of logistical items, such as packaging, for a second purpose allows fewer items to be launched. A device known as a heat melt compactor drastically reduces the volume of trash, recovers water and produces a stable tile that can be used instead of launching additional radiation protection. The fourth technology, called trash-to-gas, can benefit a mission by supplying fuel such as methane to the propulsion system. This systems engineering work will help improve logistics planning and overall mission architectures by determining the most effective use, and reuse, of all resources.

  13. A Cost Model of Item Migration in the Air Force Logistics Command Consumable Item Inventory

    Science.gov (United States)

    1986-12-01

    Long Supply . . . 65 XT. Reduced Model ANOVA Table for Long Supply . , 66 XII . Mean Responses for Long Supply . . . . . . 68 vii This i•wt nvestigates...Reduced Model ANOUA Tabla for Backarders Cl5:439) DEPENDENT VARIABLE: AVERAGE DOLLAR-WEIGHTED BACKORDERS SOURCE DF SUM OF SQUARES MEAN SQUARE MODEL 5...supply for constant and varying lead time is shown in Table XII . Both the mean difference and the 95 percent confidence interval show a considerable

  14. A Standardization Approach to Adjusting Pretest Item Statistics.

    Science.gov (United States)

    Chang, Shun-Wen; Hanson, Bradley A.; Harris, Deborah J.

    This study presents and evaluates a method of standardization that may be used by test practitioners to standardize classical item statistics when sample sizes are small. The effectiveness of this standardization approach was compared through simulation with the one-parameter logistic (1PL) and three parameter logistic (3PL) models based on the…

  15. Immediate List Recall as a Measure of Short-Term Episodic Memory: Insights from the Serial Position Effect and Item Response Theory

    Science.gov (United States)

    Gavett, Brandon E.; Horwitz, Julie E.

    2012-01-01

    The serial position effect shows that two interrelated cognitive processes underlie immediate recall of a supraspan word list. The current study used item response theory (IRT) methods to determine whether the serial position effect poses a threat to the construct validity of immediate list recall as a measure of verbal episodic memory. Archival data were obtained from a national sample of 4,212 volunteers aged 28–84 in the Midlife Development in the United States study. Telephone assessment yielded item-level data for a single immediate recall trial of the Rey Auditory Verbal Learning Test (RAVLT). Two parameter logistic IRT procedures were used to estimate item parameters and the Q1 statistic was used to evaluate item fit. A two-dimensional model better fit the data than a unidimensional model, supporting the notion that list recall is influenced by two underlying cognitive processes. IRT analyses revealed that 4 of the 15 RAVLT items (1, 12, 14, and 15) were misfit (p < .05). Item characteristic curves for items 14 and 15 decreased monotonically, implying an inverse relationship between the ability level and the probability of recall. Elimination of the four misfit items provided better fit to the data and met necessary IRT assumptions. Performance on a supraspan list learning test is influenced by multiple cognitive abilities; failure to account for the serial position of words decreases the construct validity of the test as a measure of episodic memory and may provide misleading results. IRT methods can ameliorate these problems and improve construct validity. PMID:22138320

  16. A SINGULARLY PERTURBED PROBLEM OF THIRD ORDER EQUATION WITH TWO PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A singularly perturbed problem of third order equation with two parameters is studied. Using singular perturbation method, the structure of asymptotic solutions to the problem is discussed under three possible cases of two related small parameters. The results obtained reveal the different structures and limit behaviors of the solutions in three different cases. And in comparison with the exact solutions of the autonomous equation they are relatively perfect.

  17. Two Different Bifurcation Scenarios in Neural Firing Rhythms Discovered in Biological Experiments by Adjusting Two Parameters

    Institute of Scientific and Technical Information of China (English)

    WV Xiao-Bo; MO Juan; YANG Ming-Hao; ZHENG Qiao-Hua; GU Hua-Guang; HEN Wei

    2008-01-01

    @@ Two different bifurcation scenarios, one is novel and the other is relatively simpler, in the transition procedures of neural firing patterns are studied in biological experiments on a neural pacemaker by adjusting two parameters. The experimental observations are simulated with a relevant theoretical model neuron. The deterministic non-periodic firing pattern lying within the novel bifurcation scenario is suggested to be a new case of chaos, which has not been observed in previous neurodynamical experiments.

  18. 两参数Hardy-Hilbert不等式%Hardy-Hilbert's Inequalities With Two Parameters

    Institute of Scientific and Technical Information of China (English)

    徐景实

    2007-01-01

    In this paper, the author discusses Hardy-Hilbert's inequalities with two parameters and their variants. These are generalizations of Hardy-Hilbert's inequalities with one parameter in recent literatures.%讨论了两参数Hardy-Hilbert不等式和它们的一些变形.这些不等式推广了近年文献中的单参数Hardy-Hilbert不等式.

  19. FINITE SINGULARITIES OF TOTAL MULTIPLICITY FOUR FOR A PARTICULAR SYSTEM WITH TWO PARAMETERS

    Directory of Open Access Journals (Sweden)

    Simona Cristina Nartea

    2011-07-01

    Full Text Available A particular Lotka-Volterra system with two parameters describingthe dynamics of two competing species is analyzed from the algebraicviewpoint. This study involves the invariants and the comitants of the system determinated by the application of the affine transformations group. First, the conditions for the existence of four (different or equal finite singularities for the general system are proofed, then is studied the particular case.

  20. Estimation of the reliability function for two-parameter exponentiated Rayleigh or Burr type X distribution

    Directory of Open Access Journals (Sweden)

    Anupam Pathak

    2014-11-01

    Full Text Available Abstract: Problem Statement: The two-parameter exponentiated Rayleigh distribution has been widely used especially in the modelling of life time event data. It provides a statistical model which has a wide variety of application in many areas and the main advantage is its ability in the context of life time event among other distributions. The uniformly minimum variance unbiased and maximum likelihood estimation methods are the way to estimate the parameters of the distribution. In this study we explore and compare the performance of the uniformly minimum variance unbiased and maximum likelihood estimators of the reliability function R(t=P(X>t and P=P(X>Y for the two-parameter exponentiated Rayleigh distribution. Approach: A new technique of obtaining these parametric functions is introduced in which major role is played by the powers of the parameter(s and the functional forms of the parametric functions to be estimated are not needed.  We explore the performance of these estimators numerically under varying conditions. Through the simulation study a comparison are made on the performance of these estimators with respect to the Biasness, Mean Square Error (MSE, 95% confidence length and corresponding coverage percentage. Conclusion: Based on the results of simulation study the UMVUES of R(t and ‘P’ for the two-parameter exponentiated Rayleigh distribution found to be superior than MLES of R(t and ‘P’.

  1. Logistics Innovation Process Revisited

    DEFF Research Database (Denmark)

    Gammelgaard, Britta; Su, Shong-Iee Ivan; Yang, Su-Lan

    2011-01-01

    innovation process model may include not just customers but also suppliers; logistics innovation in buyer-supplier relations may serve as an alternative to outsourcing; logistics innovation processes are dynamic and may improve supplier partnerships; logistics innovations in the supply chain are as dependent...... into the process of a logistics innovation in an oriental healthcare supply chain context. The study is, however, still limited in disclosing end-to-end supply chain benefits including concrete performance improvements at the suppliers. Examining logistics innovation processes should result not only......Purpose – The purpose of this paper is to learn more about logistics innovation processes and their implications for the focal organization as well as the supply chain, especially suppliers. Design/methodology/approach – The empirical basis of the study is a longitudinal action research project...

  2. LOGISTICS - EVOLUTION THROUGH INNOVATION

    Directory of Open Access Journals (Sweden)

    Petrache Alexandru Constantin

    2015-07-01

    Full Text Available The current economic conditions, the rapidity with which the exchange of information, resources and products in the market takes place makes the logistics seem appreciably less significant. However, the importance of logistics has been presented in the military field, through strategies that have led to wining of the great wars that mankind has seen, through the supply of troops with food or moving military equipment. The literature in the field of logistics has numerous works on this topic. But while most focuses on efficient ways of carrying out the component activities of logistics or the strategies of organizations with regard to logistics or its functions, research on dynamics of logistics is underdeveloped. To be able to propose new methods or strategies of logistic activities is necessary to understand the development of this concept, determinant factors and economic and social conditions that gave rise to such developments. Thus, after a presentation of the main landmarks of the historical development of logistics we highlight the importance of the innovation within an organization's value chain innovation, in particular, and how to conduct the business in general. Using generations of innovation identified in the literature, we determine the generation of logistics development, taking into account innovation and how to conduct business. In addition for a better highlight of the own vision over the logistics generations identified, we will present the graphical concept for each generation in part. Last but not least, for each generation identified we try to allocate the chronological landmarks featured in order to reinforce the importance played by innovation in the development of the logistics industry and to give future directions of research within this topic. The study took into account the information presented in articles, books and websites of the relevant specialty in logistics and innovation to be able to build and expose a

  3. Focused Logistics: Putting Agility in Agile Logistics

    Science.gov (United States)

    2011-05-19

    list, ahead of companies like American Express, DuPont and Coca Cola; Supports nearly 1,900 weapon systems; DLA manages eight supply chains and...maneuver units and cumbersome logistics tail that executed and supported operations during the 1st Gulf War. The initial sustainment concept in

  4. Measuring student learning with item response theory

    Directory of Open Access Journals (Sweden)

    Young-Jin Lee

    2008-01-01

    Full Text Available We investigate short-term learning from hints and feedback in a Web-based physics tutoring system. Both the skill of students and the difficulty and discrimination of items were determined by applying item response theory (IRT to the first answers of students who are working on for-credit homework items in an introductory Newtonian physics course. We show that after tutoring a shifted logistic item response function with lower discrimination fits the students’ second responses to an item previously answered incorrectly. Student skill decreased by 1.0 standard deviation when students used no tutoring between their (incorrect first and second attempts, which we attribute to “item-wrong bias.” On average, using hints or feedback increased students’ skill by 0.8 standard deviation. A skill increase of 1.9 standard deviation was observed when hints were requested after viewing, but prior to attempting to answer, a particular item. The skill changes measured in this way will enable the use of IRT to assess students based on their second attempt in a tutoring environment.

  5. Maritime logistics: contemporary issues

    National Research Council Canada - National Science Library

    Song, D.W; Panayides, P.M

    2012-01-01

    Contemporary practice and scientific innovation consider the logistics aspects of shipping and seaport operations as one of the most important areas for future development of competitive advantages...

  6. Item response theory - A first approach

    Science.gov (United States)

    Nunes, Sandra; Oliveira, Teresa; Oliveira, Amílcar

    2017-07-01

    The Item Response Theory (IRT) has become one of the most popular scoring frameworks for measurement data, frequently used in computerized adaptive testing, cognitively diagnostic assessment and test equating. According to Andrade et al. (2000), IRT can be defined as a set of mathematical models (Item Response Models - IRM) constructed to represent the probability of an individual giving the right answer to an item of a particular test. The number of Item Responsible Models available to measurement analysis has increased considerably in the last fifteen years due to increasing computer power and due to a demand for accuracy and more meaningful inferences grounded in complex data. The developments in modeling with Item Response Theory were related with developments in estimation theory, most remarkably Bayesian estimation with Markov chain Monte Carlo algorithms (Patz & Junker, 1999). The popularity of Item Response Theory has also implied numerous overviews in books and journals, and many connections between IRT and other statistical estimation procedures, such as factor analysis and structural equation modeling, have been made repeatedly (Van der Lindem & Hambleton, 1997). As stated before the Item Response Theory covers a variety of measurement models, ranging from basic one-dimensional models for dichotomously and polytomously scored items and their multidimensional analogues to models that incorporate information about cognitive sub-processes which influence the overall item response process. The aim of this work is to introduce the main concepts associated with one-dimensional models of Item Response Theory, to specify the logistic models with one, two and three parameters, to discuss some properties of these models and to present the main estimation procedures.

  7. Tertiary Logistics in the Focus of All Logistics

    OpenAIRE

    Ratko Zelenika; Mirjana Grèiæ; Helga Pavliæ Skender

    2008-01-01

    Trade logistics, traffic logistics, transport logistics and warehouse logistics are just some of the tertiary logistics which enables production processes of all economic sector products and services. Tertiary logistics representing the tertiary economic sector is the most sofisticated and the most important logistics due to the characteristics of the tertiary sector as a service sector that promotes business conditions in all economic sectors. Accordingly, tertiary logistics has a crucial ro...

  8. Logistics and logistics support in crisis management and citizen protection

    OpenAIRE

    HOLEJŠOVSKÝ, Jan

    2010-01-01

    ABSTRAKT LOGISTICS AND LOGISTICS SUPPORT IN CRISIS MANAGEMENT AND CITIZEN PROTECTION The graduation thesis on topic ``Logistics and logistics support in crisis management and citizen protection" is divided into several chapters, which in summary are a material presenting information about logistics and logistics support in crisis management and citizen protection. This was one of the aims at this work. Chapters I., II., III., IV. describe logistics and logistics support, crisis management, ci...

  9. Logistics and logistics support in crisis management and citizen protection

    OpenAIRE

    HOLEJŠOVSKÝ, Jan

    2010-01-01

    ABSTRAKT LOGISTICS AND LOGISTICS SUPPORT IN CRISIS MANAGEMENT AND CITIZEN PROTECTION The graduation thesis on topic ``Logistics and logistics support in crisis management and citizen protection" is divided into several chapters, which in summary are a material presenting information about logistics and logistics support in crisis management and citizen protection. This was one of the aims at this work. Chapters I., II., III., IV. describe logistics and logistics support, crisis management, ci...

  10. Item Discrimination and Type I Error in the Detection of Differential Item Functioning

    Science.gov (United States)

    Li, Yanju; Brooks, Gordon P.; Johanson, George A.

    2012-01-01

    In 2009, DeMars stated that when impact exists there will be Type I error inflation, especially with larger sample sizes and larger discrimination parameters for items. One purpose of this study is to present the patterns of Type I error rates using Mantel-Haenszel (MH) and logistic regression (LR) procedures when the mean ability between the…

  11. Logistics Reduction and Repurposing Beyond Low Earth Orbit

    Science.gov (United States)

    Ewert, Michael K.; Broyan, James L., Jr.

    2012-01-01

    All human space missions, regardless of destination, require significant logistical mass and volume that is strongly proportional to mission duration. Anything that can be done to reduce initial mass and volume of supplies or reuse items that have been launched will be very valuable. Often, the logistical items require disposal and represent a trash burden. Logistics contributions to total mission architecture mass can be minimized by considering potential reuse using systems engineering analysis. In NASA's Advanced Exploration Systems "Logistics Reduction and Repurposing Project," various tasks will reduce the intrinsic mass of logistical packaging, enable reuse and repurposing of logistical packaging and carriers for other habitation, life support, crew health, and propulsion functions, and reduce or eliminate the nuisance aspects of trash at the same time. Repurposing reduces the trash burden and eliminates the need for hardware whose function can be provided by use of spent logistical items. However, these reuse functions need to be identified and built into future logical systems to enable them to effectively have a secondary function. These technologies and innovations will help future logistics systems to support multiple exploration missions much more efficiently.

  12. Writing better test items.

    Science.gov (United States)

    Aucoin, Julia W

    2005-01-01

    Professional development specialists have had little opportunity to learn how to write test items to meet the expectations of today's graduate nurse. Schools of nursing have moved away from knowledge-level test items and have had to develop more application and analysis items to prepare graduates for the National Council Licensure Examination (NCLEX). This same type of question can be used effectively to support a competence assessment system and document critical thinking skills.

  13. Behavioral Operations in Logistics

    NARCIS (Netherlands)

    J. de Vries (Jelle)

    2016-01-01

    markdownabstractIn the world of logistics, a considerable share of all work is automated and performed by machines or robots. An examination of the existing logistics research reflects this image, since a substantial share of the studies focus on automated processes, and perfectly predictable system

  14. Behavioral Operations in Logistics

    NARCIS (Netherlands)

    J. de Vries (Jelle)

    2016-01-01

    markdownabstractIn the world of logistics, a considerable share of all work is automated and performed by machines or robots. An examination of the existing logistics research reflects this image, since a substantial share of the studies focus on automated processes, and perfectly predictable

  15. Improving Healthcare Logistics Processes

    DEFF Research Database (Denmark)

    Feibert, Diana Cordes

    provision whilst providing high quality care. Logistics activities in hospitals provide a significant opportunity for cost containment in healthcare through the implementation of best practices. Literature provides little guidance on how to improve healthcare logistics processes. This study investigates......Healthcare costs are increasing due to an ageing population and more sophisticated technologies and treatments. At the same time, patients expect high quality care at an affordable cost. The healthcare industry has therefore experienced increasing pressures to reduce the cost of healthcare...... logistics processes in hospitals and aims to provide theoretically and empirically based evidence for improving these processes to both expand the knowledge base of healthcare logistics and provide a decision tool for hospital logistics managers to improve their processes. Case studies were conducted...

  16. SIMULATION OF LOGISTICS PROCESSES

    Directory of Open Access Journals (Sweden)

    Yu. Taranenko

    2016-08-01

    Full Text Available The article deals with the theoretical basis of the simulation. The study shows the simulation of logistic processes in industrial countries is an integral part of many economic projects aimed at the creation or improvement of logistics systems. The paper was used model Beer Game for management of logistics processes in the enterprise. The simulation model implements in AnyLogic package. AnyLogic product allows us to consider the logistics processes as an integrated system, which allows reaching better solutions. Logistics process management involves pooling the sales market, production and distribution to ensure the temporal level of customer service at the lowest cost overall. This made it possible to conduct experiments and to determine the optimal size of the warehouse at the lowest cost.

  17. International Logistics Science Conference

    CERN Document Server

    Hompel, Michael; Meier, J

    2014-01-01

    The importance of logistics in all its variations is still increasing. New technologies emerge, new planning methods and algorithms are developed, only to face a market with a growing complexity and the need of weighting monetary costs against ecological impact. Mastering these challenges requires a scientific viewpoint on logistics, but always with applications in mind. This volume presents up-to-date logistics research in all its diversity and interconnectedness. It grew out of the “International Logistics Science Conference” (ILSC) held in Dortmund in September 2013, bringing together leading scientists and young academics from nine different countries. The conference was jointly organized by the “Efficiency Cluster Logistics” and the “Fraunhofer Institute for Material Flow and Logistics”. The Program Committee used a double blind review process to choose the 12 strongest contributions, which were then grouped in four areas: - Sustainability logistics, including electric mobility, smart inform...

  18. Prestack migration velocity analysis based on simplifi ed two-parameter moveout equation

    Institute of Scientific and Technical Information of China (English)

    Chen Hai-Feng; Li Xiang-Yang; Qian Zhong-Ping; Song Jian-Jun; Zhao Gui-Ling

    2016-01-01

    Stacking velocityVC2, vertical velocity ratioγ0, effective velocity ratioγef, and anisotropic parameterχef are correlated in the PS-converted-wave (PS-wave) anisotropic prestack Kirchhoff time migration (PKTM) velocity model and are thus difficult to independently determine. We extended the simplified two-parameter (stacking velocity VC2 and anisotropic parameterkef) moveout equation from stacking velocity analysis to PKTM velocity model updating and formed a new four-parameter (stacking velocityVC2, vertical velocity ratioγ0, effective velocity ratioγef, and anisotropic parameterkef) PS-wave anisotropic PKTM velocity model updating and processfl ow based on the simplifi ed two-parameter moveout equation. In the proposed method, first, the PS-wave two-parameter stacking velocity is analyzed to obtain the anisotropic PKTM initial velocity and anisotropic parameters; then, the velocity and anisotropic parameters are corrected by analyzing the residual moveout on common imaging point gathers after prestack time migration. The vertical velocity ratioγ0 of the prestack time migration velocity model is obtained with an appropriate method utilizing the P- and PS-wave stacked sections after level calibration. The initial effective velocity ratioγef is calculated using the Thomsen (1999) equation in combination with the P-wave velocity analysis; ultimately, the final velocity model of the effective velocity ratioγef is obtained by percentage scanning migration. This method simplifi es the PS-wave parameter estimation in high-quality imaging, reduces the uncertainty of multiparameter estimations, and obtains good imaging results in practice.

  19. Identifying Unbiased Items for Screening Preschoolers for Disruptive Behavior Problems.

    Science.gov (United States)

    Studts, Christina R; Polaha, Jodi; van Zyl, Michiel A

    2016-10-25

    OBJECTIVE : Efficient identification and referral to behavioral services are crucial in addressing early-onset disruptive behavior problems. Existing screening instruments for preschoolers are not ideal for pediatric primary care settings serving diverse populations. Eighteen candidate items for a new brief screening instrument were examined to identify those exhibiting measurement bias (i.e., differential item functioning, DIF) by child characteristics. METHOD : Parents/guardians of preschool-aged children (N = 900) from four primary care settings completed two full-length behavioral rating scales. Items measuring disruptive behavior problems were tested for DIF by child race, sex, and socioeconomic status using two approaches: item response theory-based likelihood ratio tests and ordinal logistic regression. RESULTS : Of 18 items, eight were identified with statistically significant DIF by at least one method. CONCLUSIONS : The bias observed in 8 of 18 items made them undesirable for screening diverse populations of children. These items were excluded from the new brief screening tool.

  20. A two parameter ratio-product-ratio estimator using auxiliary information

    CERN Document Server

    Chami, Peter S; Thomas, Doneal

    2012-01-01

    We propose a two parameter ratio-product-ratio estimator for a finite population mean in a simple random sample without replacement following the methodology in Ray and Sahai (1980), Sahai and Ray (1980), Sahai and Sahai (1985) and Singh and Ruiz Espejo (2003). The bias and mean square error of our proposed estimator are obtained to the first degree of approximation. We derive conditions for the parameters under which the proposed estimator has smaller mean square error than the sample mean, ratio and product estimators. We carry out an application showing that the proposed estimator outperforms the traditional estimators using groundwater data taken from a geological site in the state of Florida.

  1. Two-parameters quasi-filled function algorithm for nonlinear integer programming

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-xiang; SHANG You-lin; ZHANG Lian-sheng

    2006-01-01

    A quasi-filled function for nonlinear integer programming problem is given in this paper. This function contains two parameters which are easily to be chosen. Theoretical properties of the proposed quasi-filled function are investigated. Moreover,we also propose a new solution algorithm using this quasi-filled function to solve nonlinear integer programming problem in this paper. The examples with 2 to 6 variables are tested and computational results indicated the efficiency and reliability of the proposed quasi-filled function algorithm.

  2. Two-Parameter Radon Transformation of the Wigner Operator and Its Inverse

    Institute of Scientific and Technical Information of China (English)

    范洪义; 程海凌

    2001-01-01

    Using the technique of integration within an ordered product of operators, we reveal that a new quantum mechanical representation |x, μ,v〉exists, the eigenvector of operator μQ + νP (linear combination of coordinate Q and momentum P) with eigenvalue x, which is inherent to the two-parameter (μ, ν) Radon transformation of the Wigner operator. It turns out that the projection operator |x,μ,ν>

  3. A Two-parameter bicovariant differential calculus on the (1 + 2)-dimensional q-superspace

    Science.gov (United States)

    Yasar, Ergün

    2016-01-01

    We construct a two-parameter bicovariant differential calculus on ℛq1/2 with the help of the covariance point of view using the Hopf algebra structure of ℛq1/2. To achieve this, we first use the consistency of calculus and the approach of R-matrix which satisfies both ungraded and graded Yang-Baxter equations. In particular, based on this differential calculus, we investigate Cartan-Maurer forms for this q-superspace. Finally, we obtain the quantum Lie superalgebra corresponding the Cartan-Maurer forms.

  4. Cradle-to-Grave Logistic Technologies for Exploration Missions

    Science.gov (United States)

    Broyan, James L.; Ewert, Michael K.; Shull, Sarah

    2013-01-01

    Human exploration missions under study are very limited by the launch mass capacity of exiting and planned vehicles. The logistical mass of crew items is typically considered separate from the vehicle structure, habitat outfitting, and life support systems. Consequently, crew item logistical mass is typically competing with vehicle systems for mass allocation. NASA is Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) Project is developing four logistics technologies guided by a systems engineering cradle-to-grave approach to enable used crew items to augment vehicle systems. Specifically, AES LRR is investigating the direct reduction of clothing mass, the repurposing of logistical packaging, the processing of spent crew items to benefit radiation shielding and water recovery, and the conversion of trash to propulsion supply gases. The systematic implementation of these types of technologies will increase launch mass efficiency by enabling items to be used for secondary purposes and improve the habitability of the vehicle as the mission duration increases. This paper provides a description, benefits, and challenges of the four technologies under development and a status of progress at the mid ]point of the three year AES project.

  5. AN OVERVIEW ON RETAIL REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-07-01

    Full Text Available This article is a theoretical approach on retail reverse logistics. Environmental concern and the current marketing strategy have spurred retailers to implement strategies to facilitate product returns from end customers. Reverse logistics, indicating the process of this return flow, encompasses such activities as the movement of returned products, facilities to accommodate returned items, and overall remedy process for returned items. The retail industry, under great competitive pressure, has used return policies as a competitive weapon. Grocery retailers were the first to begin to focus serious attention on the problem of returns and to develop reverse logistics innovations. Grocery retailers first developed innovations such as reclamation centers. Reclamation centers, in turn, led to the establishment of centralized return centers. Centralizing returns has led to significant benefits for most firms that have implemented them. Over the last several years, retailers have consolidated. Now, more than ever, reverse logistics is seen as being important. This reverse distribution activity can be crucial to the survival of companies, because the permanent goodwill of the company is at stake. Businesses succeed because they respond to both external and internal changes and adjust in an effective manner to remain competitive.

  6. Representations of coherent and squeezed states in an extended two-parameter Fock space

    Institute of Scientific and Technical Information of China (English)

    M. K. Tavassoly; M. H. Lake

    2012-01-01

    Recently an f-deformed Fock space which is spanned by |n〉λ was introduced.These bases are the eigenstates of a deformed non-Hermitian Hamiltonian.In this contribution,we will use rather new nonorthogonal basis vectors for the construction of coherent and squeezed states,which in special case lead to the earlier known states.For this purpose,we first generalize the previously introduced Fock space spanned by |n〉λ bases,to a new one,spanned by extended two-parameters bases |n〉λ1,λ2.These bases are now the eigenstates of a non-Hermitian Hamiltonian Hλ1,λ2 =a(+)1,λ2a +1/2,where a(+)λ1,λ2 =a(+) + λ1a + λ2 and a are,respectively,the deformed creation and ordinary bosonic annihilation operators.The bases |n〉λ1,λ2 are nonorthogonal (squeezed states),but normalizable.Then,we deduce the new representations of coherent and squeezed states in our two-parameter Fock space.Finally,we discuss the quantum statistical properties,as well as the non-classical properties of the obtained states numerically.

  7. Security in Logistics

    Science.gov (United States)

    Cempírek, Václav; Nachtigall, Petr; Široký, Jaromír

    2016-12-01

    This paper deals with security of logistic chains according to incorrect declaration of transported goods, fraudulent transport and forwarding companies and possible threats caused by political influences. The main goal of this paper is to highlight possible logistic costs increase due to these fraudulent threats. An analysis of technological processes will beis provided, and an increase of these transport times considering the possible threatswhich will beis evaluated economic costs-wise. In the conclusion, possible threat of companies'` efficiency in logistics due to the costs`, means of transport and increase in human resources` increase will beare pointed out.

  8. Applied logistic regression

    CERN Document Server

    Hosmer, David W; Sturdivant, Rodney X

    2013-01-01

     A new edition of the definitive guide to logistic regression modeling for health science and other applications This thoroughly expanded Third Edition provides an easily accessible introduction to the logistic regression (LR) model and highlights the power of this model by examining the relationship between a dichotomous outcome and a set of covariables. Applied Logistic Regression, Third Edition emphasizes applications in the health sciences and handpicks topics that best suit the use of modern statistical software. The book provides readers with state-of-

  9. Green Maritime Logistics

    DEFF Research Database (Denmark)

    Psaraftis, Harilaos N.

    2016-01-01

    By green maritime logistics we mean achieving an acceptable environmental performance of the maritime transport logistical supply chain while at the same time respecting traditional economic criteria. In this paper the environmental focus is on maritime emissions. Achieving such goal may involve...... several trade-offs, and win-win solutions are typically sought. However, finding these solutions may be more difficult than may appear at first glance. The purpose of this paper is to provide a concise overview of the challenges of green maritime logistics and present some examples, both for greenhouse...

  10. Calibration of an Item Bank for the Assessment of Basque Language Knowledge

    Science.gov (United States)

    Lopez-Cuadrado, Javier; Perez, Tomas A.; Vadillo, Jose A.; Gutierrez, Julian

    2010-01-01

    The main requisite for a functional computerized adaptive testing system is the need of a calibrated item bank. This text presents the tasks carried out during the calibration of an item bank for assessing knowledge of Basque language. It has been done in terms of the 3-parameter logistic model provided by the item response theory. Besides, this…

  11. Logistics and Inventory System -

    Data.gov (United States)

    Department of Transportation — The Logistics and Inventory System (LIS) is the agencys primary supply/support automation tool. The LIS encompasses everything from order entry by field specialists...

  12. Green Logistics Management

    Science.gov (United States)

    Chang, Yoon S.; Oh, Chang H.

    Nowadays, environmental management becomes a critical business consideration for companies to survive from many regulations and tough business requirements. Most of world-leading companies are now aware that environment friendly technology and management are critical to the sustainable growth of the company. The environment market has seen continuous growth marking 532B in 2000, and 590B in 2004. This growth rate is expected to grow to 700B in 2010. It is not hard to see the environment-friendly efforts in almost all aspects of business operations. Such trends can be easily found in logistics area. Green logistics aims to make environmental friendly decisions throughout a product lifecycle. Therefore for the success of green logistics, it is critical to have real time tracking capability on the product throughout the product lifecycle and smart solution service architecture. In this chapter, we introduce an RFID based green logistics solution and service.

  13. Logistics innovation development

    DEFF Research Database (Denmark)

    Pedrosa, Alex; Blazevic, Vera; Jasmand, Claudia

    2014-01-01

    Purpose This paper aims to investigate the microfoundations—boundary-spanning employees activities and behaviors—of deepening and broadening customer knowledge during logistics innovation development. Design/methodology/approach A multiple case study approach (six case studies) was adopted...... to investigate the role of boundary-spanning employees in deepening and broadening customer knowledge while developing logistics service innovations. Findings The results show that boundary-spanning employees’ engage sequentially in deepening and broadening customer knowledge throughout the logistics innovation......, this paper contributes to the understanding of the individuals’ behaviors underlying organization-level phenomena, such as logistics service providers’ customer knowledge acquisition. Practical implications (if applicable) Our findings illustrate that boundary-spanning employees might be well advised...

  14. Sustainable logistics in practice

    OpenAIRE

    Fitria, Irza

    2011-01-01

    Improved logistical performance is one of the tools to mitigate greenhouse gases emissions from freight transport. The production company and transportation company should find the practice to decrease the emissions from their activity in distributions of goods. In this thesis, the sustainable logistics in practice in focal company (Ekornes) is studied. The potential improvement in relation to sustainable transportation principle is explained. Through qualitative method research, the theory r...

  15. Operational Logistics Wargame

    Science.gov (United States)

    2001-12-01

    Gettysburg CG 64 Ticonderoga 0 40 3 Nicholson DD 982 Spruance 20 0 4 Cole DDG 67 Arleigh Burke 60 20 5 Rueben James FFG 57 Perry 0 20 6 Halyburton FFG 40...the Operational Logistics Wargame and depicted in this document were obtained from a variety of sources including theses by Lt J.R. Sterba and Lt A.W...Consumption: Update, NPS, July 1996. Sterba , J. R., Operational Maneuver from the Sea Logistics Training Aid, NPS, September 1999, Troxell, A

  16. Lunar Commercial Mining Logistics

    Science.gov (United States)

    Kistler, Walter P.; Citron, Bob; Taylor, Thomas C.

    2008-01-01

    Innovative commercial logistics is required for supporting lunar resource recovery operations and assisting larger consortiums in lunar mining, base operations, camp consumables and the future commercial sales of propellant over the next 50 years. To assist in lowering overall development costs, ``reuse'' innovation is suggested in reusing modified LTS in-space hardware for use on the moon's surface, developing product lines for recovered gases, regolith construction materials, surface logistics services, and other services as they evolve, (Kistler, Citron and Taylor, 2005) Surface logistics architecture is designed to have sustainable growth over 50 years, financed by private sector partners and capable of cargo transportation in both directions in support of lunar development and resource recovery development. The author's perspective on the importance of logistics is based on five years experience at remote sites on Earth, where remote base supply chain logistics didn't always work, (Taylor, 1975a). The planning and control of the flow of goods and materials to and from the moon's surface may be the most complicated logistics challenges yet to be attempted. Affordability is tied to the innovation and ingenuity used to keep the transportation and surface operations costs as low as practical. Eleven innovations are proposed and discussed by an entrepreneurial commercial space startup team that has had success in introducing commercial space innovation and reducing the cost of space operations in the past. This logistics architecture offers NASA and other exploring nations a commercial alternative for non-essential cargo. Five transportation technologies and eleven surface innovations create the logistics transportation system discussed.

  17. Conference Logistics Management 2013

    CERN Document Server

    Haasis, Hans-Dietrich; Kopfer, Herbert; Kotzab, Herbert; Schönberger, Jörn

    2015-01-01

    This contributed volume contains the collected research papers presented at the Logistik-Management-Konferenz 2013 organized by the VHB Wissenschaftliche Kommission Logistik, held in Bremen 2013. The papers reflect the current state-of-the-art in logistics and supply chain management, focusing on environmental sustainability in logistics and supply chain network dynamics and control. The target audience primarily comprises research experts in the field as well as practitioners but the book may also be beneficial for graduate students.

  18. Chaos and stability in a two-parameter family of convex billiard tables

    CERN Document Server

    Bálint, Péter; Hernández-Tahuilán, Jorge; Sanders, David P

    2010-01-01

    We study, by numerical simulations and semi-rigorous arguments, a two-parameter family of convex, two-dimensional billiard tables, generalizing the one-parameter class of oval billiards of Benettin--Strelcyn [Phys. Rev. A 17, 773 (1978)]. We observe interesting dynamical phenomena when the billiard tables are continuously deformed from the integrable circular billiard to different versions of completely-chaotic stadia. In particular, we conjecture that a new class of ergodic billiard tables is obtained in certain regions of the two-dimensional parameter space, when the billiards are close to skewed stadia. We provide heuristic arguments supporting this conjecture, and give numerical confirmation using the powerful method of Lyapunov-weighted dynamics.

  19. Thermodynamic geometry, condensation and Debye model of two-parameter deformed statistics

    Science.gov (United States)

    Mohammadzadeh, Hosein; Azizian-Kalandaragh, Yashar; Cheraghpour, Narges; Adli, Fereshteh

    2017-08-01

    We consider the statistical distribution function of a two parameter deformed system, namely qp-deformed bosons and fermions. Using a thermodynamic geometry approach, we derive the thermodynamic curvature of an ideal gas with particles obeying qp-bosons and qp-fermions. We show that the intrinsic statistic interaction of qp-bosons is attractive in all physical ranges, while it is repulsive for qp-fermions. Also, the thermodynamic curvature of qp-boson gas is singular at a specified value of fugacity and therefore, a phase transition such as Bose-Einstein condensation can take place. In the following, we compare the experimental and theoretical results of temperature-dependent specific heat capacity of some metallic materials in the framework of q and qp-deformed algebras.

  20. A two-parameter nondiffusive heat conduction model for data analysis in pump-probe experiments

    Science.gov (United States)

    Ma, Yanbao

    2014-12-01

    Nondiffusive heat transfer has attracted intensive research interests in last 50 years because of its importance in fundamental physics and engineering applications. It has unique features that cannot be described by the Fourier law. However, current studies of nondiffusive heat transfer still focus on studying the effective thermal conductivity within the framework of the Fourier law due to a lack of a well-accepted replacement. Here, we show that nondiffusive heat conduction can be characterized by two inherent material properties: a diffusive thermal conductivity and a ballistic transport length. We also present a two-parameter heat conduction model and demonstrate its validity in different pump-probe experiments. This model not only offers new insights of nondiffusive heat conduction but also opens up new avenues for the studies of nondiffusive heat transfer outside the framework of the Fourier law.

  1. Two-parameter non-linear spacetime perturbations gauge transformations and gauge invariance

    CERN Document Server

    Bruni, M; Sopuerta, C F; Bruni, Marco; Gualtieri, Leonardo; Sopuerta, Carlos F.

    2003-01-01

    An implicit fundamental assumption in relativistic perturbation theory is that there exists a parametric family of spacetimes that can be Taylor expanded around a background. The choice of the latter is crucial to obtain a manageable theory, so that it is sometime convenient to construct a perturbative formalism based on two (or more) parameters. The study of perturbations of rotating stars is a good example: in this case one can treat the stationary axisymmetric star using a slow rotation approximation (expansion in the angular velocity Omega), so that the background is spherical. Generic perturbations of the rotating star (say parametrized by lambda) are then built on top of the axisymmetric perturbations in Omega. Clearly, any interesting physics requires non-linear perturbations, as at least terms lambda Omega need to be considered. In this paper we analyse the gauge dependence of non-linear perturbations depending on two parameters, derive explicit higher order gauge transformation rules, and define gaug...

  2. Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws

    CERN Document Server

    Kipping, David M

    2013-01-01

    Stellar limb darkening affects a wide range of astronomical measurements and is frequently modeled with a parametric model using polynomials in the cosine of the angle between the line of sight and the emergent intensity. Two-parameter laws are particularly popular for cases where one wishes to fit freely for the limb darkening coefficients (i.e. an uninformative prior) due to the compact prior volume and the fact more complex models rarely obtain unique solutions with present data. In such cases, we show that the two limb darkening coefficients are constrained by three physical boundary conditions, describing a triangular region in the two-dimensional parameter space. We show that uniformly distributed samples may be drawn from this region with optimal efficiency by a technique developed by computer graphical programming: triangular sampling. Alternatively, one can use make draws using a uniform, bivariate Dirichlet distribution. We provide simple expressions for these parametrizations for both techniques ap...

  3. Quantum transport and two-parameter scaling at the surface of a weak topological insulator.

    Science.gov (United States)

    Mong, Roger S K; Bardarson, Jens H; Moore, Joel E

    2012-02-17

    Weak topological insulators have an even number of Dirac cones in their surface spectrum and are thought to be unstable to disorder, which leads to an insulating surface. Here we argue that the presence of disorder alone will not localize the surface states; rather, the presence of a time-reversal symmetric mass term is required for localization. Through numerical simulations, we show that in the absence of the mass term the surface always flow to a stable metallic phase and the conductivity obeys a one-parameter scaling relation, just as in the case of a strong topological insulator surface. With the inclusion of the mass, the transport properties of the surface of a weak topological insulator follow a two-parameter scaling form.

  4. On Calculating the Hougaard Measure of Skewness in a Nonlinear Regression Model with Two Parameters

    Directory of Open Access Journals (Sweden)

    S. A. EL-Shehawy

    2009-01-01

    Full Text Available Problem statement: This study presented an alternative computational algorithm for determining the values of the Hougaard measure of skewness as a nonlinearity measure in a Nonlinear Regression model (NLR-model with two parameters. Approach: These values indicated a degree of a nonlinear behavior in the estimator of the parameter in a NLR-model. Results: We applied the suggested algorithm on an example of a NLR-model in which there is a conditionally linear parameter. The algorithm is mainly based on many earlier studies in measures of nonlinearity. The algorithm was suited for implementation using computer algebra systems such as MAPLE, MATLAB and MATHEMATICA. Conclusion/Recommendations: The results with the corresponding output the same considering example will be compared with the results in some earlier studies.

  5. Logistics Indicators Could Improve Logistics Performance of Hospitals

    Directory of Open Access Journals (Sweden)

    Wajong Andre M. R.

    2017-01-01

    Full Text Available Hospitals are institutions in which numerous transactions take place. A significant amount of those transactions happen in the realm of logistics. Logistifics is one of the concern of the hospital’s managing entities. Hospitals must provide a variety of logistics within a limited amount of time. The implementation of hospital logistics indicators were expected to assist the management in improving performance in the logistics units of hospitals in the Province of Jakarta. It was expected that by attending to a number of variables, namely information technology support, logistics management, logistics business intelligence, and logistics performance, such improvement could be achieved. The result of this study provided a description of major indicators that could improve the logistics performance in hospital industry located within the Province of Jakarta. Index Terms: hospital logistics indicator, information technology support, logistics business intelligence, logistic management, logistics performance.

  6. Research on the Logistics Supply Chain in Port Logistics Transportation

    Directory of Open Access Journals (Sweden)

    Wang Yan-liang

    2013-11-01

    Full Text Available The aim of this study is to improve and increase the logistics system effectiveness and to solve the problem of optimal movement of different flows. Logistics transport carrying the world on material resources transfer exchange important mission and economic development and our lives are closely linked, logistics chain logistics transport occupies an important position and in the e logistics chain in port logistics has play a decisive role. For many coastal countries port logistics is the economic lifeline of the country, on China's economic development role as important, port logistics transport bear the material exchange with the external communication of important role, so the Chinese port logistics transportation research, clear port logistics transportation, current situation, find the existing problems in the light of the problem, to find a suitable method for solving has great realistic meaning. To promote logistics development, improve the logistics supply chain system has play an important role in this filed.

  7. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    Science.gov (United States)

    Broyan, James Lee, Jr.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items, and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by one manifest item having two purposes rather than two manifest items each having only one purpose. This paper provides the status of each of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACSs) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags for potential reuse on-orbit. Autonomous logistics management is using radio frequency identification (RFID) to track items and thus reduce crew time for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. A heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is under way. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology.

  8. Humanitarian response: improving logistics to save lives.

    Science.gov (United States)

    McCoy, Jessica

    2008-01-01

    Each year, millions of people worldwide are affected by disasters, underscoring the importance of effective relief efforts. Many highly visible disaster responses have been inefficient and ineffective. Humanitarian agencies typically play a key role in disaster response (eg, procuring and distributing relief items to an affected population, assisting with evacuation, providing healthcare, assisting in the development of long-term shelter), and thus their efficiency is critical for a successful disaster response. The field of disaster and emergency response modeling is well established, but the application of such techniques to humanitarian logistics is relatively recent. This article surveys models of humanitarian response logistics and identifies promising opportunities for future work. Existing models analyze a variety of preparation and response decisions (eg, warehouse location and the distribution of relief supplies), consider both natural and manmade disasters, and typically seek to minimize cost or unmet demand. Opportunities to enhance the logistics of humanitarian response include the adaptation of models developed for general disaster response; the use of existing models, techniques, and insights from the literature on commercial supply chain management; the development of working partnerships between humanitarian aid organizations and private companies with expertise in logistics; and the consideration of behavioral factors relevant to a response. Implementable, realistic models that support the logistics of humanitarian relief can improve the preparation for and the response to disasters, which in turn can save lives.

  9. Information Support of Processes in Warehouse Logistics

    Directory of Open Access Journals (Sweden)

    Gordei Kirill

    2013-11-01

    Full Text Available In the conditions of globalization and the world economic communications, the role of information support of business processes increases in various branches and fields of activity. There is not an exception for the warehouse activity. Such information support is realized in warehouse logistic systems. In relation to territorial administratively education, the warehouse logistic system gets a format of difficult social and economic structure which controls the economic streams covering the intermediary, trade and transport organizations and the enterprises of other branches and spheres. Spatial movement of inventory items makes new demands to participants of merchandising. Warehousing (in the meaning – storage – is one of the operations entering into logistic activity, on the organization of a material stream, as a requirement. Therefore, warehousing as "management of spatial movement of stocks" – is justified. Warehousing, in such understanding, tries to get rid of the perception as to containing stocks – a business expensive. This aspiration finds reflection in the logistic systems working by the principle: "just in time", "economical production" and others. Therefore, the role of warehouses as places of storage is transformed to understanding of warehousing as an innovative logistic system.

  10. Differential functioning of Bender Visual-Motor Gestalt Test items.

    Science.gov (United States)

    Sisto, Fermino Fernandes; Dos Santos, Acácia Aparecida Angeli; Noronha, Ana Paula Porto

    2010-02-01

    Differential Item Functioning (DIF) refers to items that do not function the same way for comparable members of different groups. The present study focuses on analyzing and classifying sex-related differential item functioning in the Bender Visual-Motor Gestalt Test. Subjects were 1,052 children attending public schools (513 boys, 539 girls, ages 6-10 years). The protocols were scored using the Bender Graduated Scoring System, which evaluates only the distortion criterion using the Rasch logistic response model. The scoring system fit the Rasch model, although two items were found to be biased by sex. When analyzing differential functioning of items for boys and girls separately, the number of differentially functioning items was equal.

  11. Evaluation of item candidates: the PROMIS qualitative item review.

    Science.gov (United States)

    DeWalt, Darren A; Rothrock, Nan; Yount, Susan; Stone, Arthur A

    2007-05-01

    One of the PROMIS (Patient-Reported Outcome Measurement Information System) network's primary goals is the development of a comprehensive item bank for patient-reported outcomes of chronic diseases. For its first set of item banks, PROMIS chose to focus on pain, fatigue, emotional distress, physical function, and social function. An essential step for the development of an item pool is the identification, evaluation, and revision of extant questionnaire items for the core item pool. In this work, we also describe the systematic process wherein items are classified for subsequent statistical processing by the PROMIS investigators. Six phases of item development are documented: identification of extant items, item classification and selection, item review and revision, focus group input on domain coverage, cognitive interviews with individual items, and final revision before field testing. Identification of items refers to the systematic search for existing items in currently available scales. Expert item review and revision was conducted by trained professionals who reviewed the wording of each item and revised as appropriate for conventions adopted by the PROMIS network. Focus groups were used to confirm domain definitions and to identify new areas of item development for future PROMIS item banks. Cognitive interviews were used to examine individual items. Items successfully screened through this process were sent to field testing and will be subjected to innovative scale construction procedures.

  12. Pengendalian Persediaan Primary Items dalam Logistik Konstruksi

    Directory of Open Access Journals (Sweden)

    Lady Lisya

    2016-09-01

    Full Text Available Construction logistics are activities that consist of ordering, storage and transportation of materials of construction projects. Storage material is logistics activity that ensure the availability of materials in project site. Generally, material storage activities have been conducted at the project site. Logistics construction is aimed to support the project activities that the completion schedule has been set. Construction logistics issues is determining the schedule of ordering materials so that the project can be implemented on schedule. The purpose of research is to determine the optimum ordering period for the primary items on the main building structure construction and designing inventory control cards as a mechanism for monitoring procurement of materials. This research has been obtained optimal ordering period for the primary items of main building structure with elements of the work using Fixed Period Requirement method. Inventories were already meet the material requirement of each period. Material management has been conducted based grouping approach as many as 31 groups. In addition, this research has proposed the inventory control cards as an instrument for material procurement monitoring. The implications of inventory control cards are coordinate contracting parties with vendors to plan the replenishment  of materials to meet the work schedule. Further research can be developed with other aspects such as integrated material order system between contractors and vendors to consider the safety stock. In addition, the information system for planning material is an important consideration for construction projects with large scale so that the companies can plan primary items inventory and other materials in the projects completion more easily, quickly and accurately.

  13. Education in logistics and training of non-logistic personnel

    Directory of Open Access Journals (Sweden)

    Marko D. Andrejić

    2011-01-01

    Full Text Available The significance of education in logistics and education and training of cadets who belong to non-logistic services (non-logistic personnel will be presented. The logistical aspects of education of non-logistic personnel are elaborated as well as the knowledge in the area of logistics which is necessary to be transferred through the educational process to non-logistic personnel for the successful accomplishment of their functional duties. A general approach and the methods of logistics education and improvement of non-logistic personnel are presented as well as the institutional prerequisites necessary for improving the quality of logistics education and training. The quality of the knowledge in this area and its implementation into the methods of thinking and decision making of non-logistic personnel affect the cooperation between the non-logistic and the logistic personnel, directly contributing to the quality of life and working conditions of units and institutions as well as to the quality and synergy in task accomplishments in the framework defined by the missions of the Army of Serbia. The necessary content and means of its transfer to cadets are discussed since they are supposed to be available at all levels and forms of education, depending on the previous cadet education levels. The theoretical bases and experiences shown are of general character and they have a universal application in the process of education. Introduction In our recent defense theory and operational practice, logistics education of non-logistic personnel is not sufficiently analyzed either in organizational or technological aspects, considering the concept and the logic of a systematic and a situational approach. The analysis of the experiences gained from operational practice shows a slight decrease in the quality of task accomplishment due to the lack of necessary logistic knowledge and habits as well as an increased communication gap between logistic and non-logistic

  14. Logistics costs of the enterprise

    OpenAIRE

    Andrea Rosová

    2007-01-01

    The article describe a problem of specification and systematization of enterprise’s logistics costs. With in a growing division of labour, also logistics costs increase their part in enterprises total costs.Almost all decisions about products and production in general, influence logistics processes even logistics costs and performances.In present is not clear enough, which of the cost-particles are relevant fot logistics costs, because some of logistics cost-particles accounts within overhead...

  15. Measures of effectiveness in logistics

    OpenAIRE

    Schrady, David A.

    1989-01-01

    Approved for public release; distribution is unlimited. This report examines measures of effectiveness in naval logistics. Logistics is a warfare support function and it is most desirable to be able to relate resources committed for logistics capabilities to warfare outcomes. In general this cannot be done. Examples of the sorts of measures of effectiveness used in acquisition logistics and in in-service support are given. Battle group logistics, a part of operational logistics, is examine...

  16. Geo-Information Logistical Modeling

    Directory of Open Access Journals (Sweden)

    Nikolaj I. Kovalenko

    2014-11-01

    Full Text Available This paper examines geo-information logistical modeling. The author illustrates the similarities between geo-informatics and logistics in the area of spatial objectives; illustrates that applying geo-data expands the potential of logistics; brings to light geo-information modeling as the basis of logistical modeling; describes the types of geo-information logistical modeling; describes situational geo-information modeling as a variety of geo-information logistical modeling.

  17. Space Station fluid management logistics

    Science.gov (United States)

    Dominick, Sam M.

    1990-01-01

    Viewgraphs and discussion on space station fluid management logistics are presented. Topics covered include: fluid management logistics - issues for Space Station Freedom evolution; current fluid logistics approach; evolution of Space Station Freedom fluid resupply; launch vehicle evolution; ELV logistics system approach; logistics carrier configuration; expendable fluid/propellant carrier description; fluid carrier design concept; logistics carrier orbital operations; carrier operations at space station; summary/status of orbital fluid transfer techniques; Soviet progress tanker system; and Soviet propellant resupply system observations.

  18. Green Maritime Logistics

    DEFF Research Database (Denmark)

    Psaraftis, Harilaos N.

    2014-01-01

    chain management. The traditional analysis of these problems has been in terms of cost- benefit and other optimization criteria from the point of view of the logistics provider, carrier, shipper, or other end-user. Such traditional analysis by and large either ignores environmental issues, or considers......Typical problems in maritime logistics include, among others, optimal ship speed, ship routing and scheduling, fleet deployment, fleet size and mix, weather routing, intermodal network design, modal split, transshipment, queuing at ports, terminal management, berth allocation, and total supply...... them of secondary importance. Green maritime logistics tries to bring the environmental dimension into the problem, and specifically the dimension of emissions reduction, by analyzing various trade-offs and exploring ‘win-win’ solutions. This talk takes a look at the trade-offs that are at stake...

  19. Efficiency and Logistics

    CERN Document Server

    Hompel, Michael; Klumpp, Matthias

    2013-01-01

    The „EffizienzCluster LogistikRuhr“ was a winner in the Leading Edge Science Cluster competition run by the German federal Ministry of Education and Research. The mission and aim of the „EffizienzCluster LogistikRuhr“ is to facilitate tomorrow’s individuality – in the sense of individual goods supply, mobility, and production – using 75 percent of today’s resources. Efficiency – both in economical and ecological terms – is enabled by state-of-the-art and innovative logistical solutions including transportation, production and intralogistics. These proceedings “Efficiency and Logistics” give first answers from 27 research projects as an insight into the current state of research of Europe’s leading research and development cluster in logistics and as a contribution to the discussion on how logistics as a science can help to cope with foreseeable resource shortage and sustainability as global challenges.

  20. Logistics innovation development

    DEFF Research Database (Denmark)

    Pedrosa, Alex; Blazevic, Vera; Jasmand, Claudia

    2015-01-01

    illustrate that boundary-spanning employees are well advised to concentrate on either deepening or broadening their customer knowledge in a single stage of the logistics innovation development process but switch between these two knowledge acquisition approaches from stage-to-stage to leverage customer...... about customers for the development of innovations. Design/methodology/approach — Qualitative research based on multiple semi-structured interviews with boundary-spanning employees of six logistics service providers was conducted to explore the deepening and broadening of customer knowledge during...... knowledge throughout the logistics innovation development process. Yet, the specific sequence depends on the type of innovation developed (customized versus standardized). Customer knowledge tends to be deepened in one-on-one interactions, while knowledge tends to be broadened in interactions with numerous...

  1. Practical Session: Logistic Regression

    Science.gov (United States)

    Clausel, M.; Grégoire, G.

    2014-12-01

    An exercise is proposed to illustrate the logistic regression. One investigates the different risk factors in the apparition of coronary heart disease. It has been proposed in Chapter 5 of the book of D.G. Kleinbaum and M. Klein, "Logistic Regression", Statistics for Biology and Health, Springer Science Business Media, LLC (2010) and also by D. Chessel and A.B. Dufour in Lyon 1 (see Sect. 6 of http://pbil.univ-lyon1.fr/R/pdf/tdr341.pdf). This example is based on data given in the file evans.txt coming from http://www.sph.emory.edu/dkleinb/logreg3.htm#data.

  2. Sub-tangentially loaded and damped Beck's columns on two-parameter elastic foundation

    Science.gov (United States)

    Lee, Jun-Seok; Kim, Nam-Il; Kim, Moon-Young

    2007-10-01

    The dynamic stability of the damped Beck's column on two-parameter elastic foundation is investigated by using Hermitian beam elements. For this purpose, based on the extended Hamilton's principle, the dimensionless finite element (FE) formulation using the Hermitian interpolation function is presented. First, the mass matrix, the external and internal damping matrices, the elastic and the geometric stiffness matrices, Winkler and Pasternak foundation matrices, and the load correction stiffness matrix due to the sub-tangential follower force are obtained. Then, evaluation procedure for the flutter and divergence loads of the non-conservative system and the time history analysis using the Newmark- β method are shortly described. Finally, the influences of various parameters on the dynamic stability of non-conservative systems are newly addressed: (1) variation of the second flutter load due to sub-tangentiality, (2) influences of the external and the internal damping on flutter loads by analysis of complex natural frequencies, (3) the effect of the growth rate of motion in a finite time interval using time history analysis, and (4) fluctuation of divergence and flutter loads due to Winkler and Pasternak foundations.

  3. Explicit formula for the Holevo bound for two-parameter qubit-state estimation problem

    Science.gov (United States)

    Suzuki, Jun

    2016-04-01

    The main contribution of this paper is to derive an explicit expression for the fundamental precision bound, the Holevo bound, for estimating any two-parameter family of qubit mixed-states in terms of quantum versions of Fisher information. The obtained formula depends solely on the symmetric logarithmic derivative (SLD), the right logarithmic derivative (RLD) Fisher information, and a given weight matrix. This result immediately provides necessary and sufficient conditions for the following two important classes of quantum statistical models; the Holevo bound coincides with the SLD Cramér-Rao bound and it does with the RLD Cramér-Rao bound. One of the important results of this paper is that a general model other than these two special cases exhibits an unexpected property: the structure of the Holevo bound changes smoothly when the weight matrix varies. In particular, it always coincides with the RLD Cramér-Rao bound for a certain choice of the weight matrix. Several examples illustrate these findings.

  4. Representations of Coherent and Squeezed States in an Extended Two-parameters Fock Space

    CERN Document Server

    Tavassoly, M K

    2012-01-01

    Recently a $f$-deformed Fock space which is spanned by $|n>_{\\lambda}$ has been introduced. These bases are indeed the eigen-states of a deformed non-Hermitian Hamiltonian. In this contribution, we will use a rather new non-orthogonal basis vectors for the construction of coherent and squeezed states, which in special case lead to the earlier known states. For this purpose, we first generalize the previously introduced Fock space spanned by $|n>_{\\lambda}$ bases, to a new one, spanned by an extended two-parameters bases $|n>_{\\lambda_{1},\\lambda_{2}}$. These bases are now the eigen-states of a non-Hermitian Hamiltonian $H_{\\lambda_{1},\\lambda_{2}}=a^{\\dagger}_{\\lambda_{1},\\lambda_{2}}a+1/2$, where $a^{\\dagger}_{\\lambda_{1},\\lambda_{2}}=a^{\\dagger}+\\lambda_{1}a + \\lambda_{2}$ and $a$ are respectively, the deformed creation and ordinary bosonic annihilation operators. The bases $|n>_{\\lambda_{1},\\lambda_{2}}$ are non-orthogonal (squeezed states), but normalizable. Then, we deduce the new representations of cohe...

  5. A Logistics Revolution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The entry of international industry leaders is stirring up profound logistics changes in China After 23 rounds of negotiations in the past two years. FedEx's first transit center in China is to be built in the Guangzhou Baiyun International Airport soon.

  6. Logistics innovation development

    DEFF Research Database (Denmark)

    Pedrosa, Alex; Blazevic, Vera; Jasmand, Claudia

    2015-01-01

    about customers for the development of innovations. Design/methodology/approach — Qualitative research based on multiple semi-structured interviews with boundary-spanning employees of six logistics service providers was conducted to explore the deepening and broadening of customer knowledge during...

  7. Logistics Services Communication

    CERN Multimedia

    2006-01-01

    Members of the personnel are invited to take note that only parcels corresponding to official orders or contracts will be handled at CERN. Individuals are not authorised to have private merchandise delivered to them at CERN and private deliveries will not be accepted by the Goods Reception services. Thank you for your understanding. Logistics Services - FI Department - 79947

  8. Logistics Services Communication

    CERN Multimedia

    2006-01-01

    Members of the personnel are invited to take note that only parcels corresponding to official orders or contracts will be handled at CERN. Individuals are not authorisedto have private merchandise delivered to them at CERN and private deliveries will not be accepted by the Goods Reception services. Thank you for your understanding. Logistics Services - FI Department - 79947

  9. Bonded+ Logistics=?

    Institute of Scientific and Technical Information of China (English)

    WangBin

    2004-01-01

    Could “bonded” and “lo gistics” be effectively related?This concerns not only the future development of its port logistics but also points out in real practice a new way of system transformation for the Chinese bonded areas.And it is with such questions in mind

  10. Maritime logistics: contemporary issues

    National Research Council Canada - National Science Library

    Song, D.W; Panayides, P.M

    2012-01-01

    ... in business and for study and research. This book is the first of its kind, adopting the innovative approach of dealing with the overlap between shipping, ports and logistics and covering the current issues having a significant impact on the industry...

  11. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    Science.gov (United States)

    Broyan, James L.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by replacing some items on the manifest. Examples include reuse of trash as radiation shielding or propellant. This paper provides the status of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACS) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station (ISS) technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags (MCTBs) for potential reuse on orbit. Autonomous logistics management (ALM) is using radio frequency identification (RFID) to track items and thus reduce crew requirements for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. Development of a heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is underway. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology

  12. Studies on Logistics and Logistics Technology of China

    Institute of Scientific and Technical Information of China (English)

    LuoYixin

    2005-01-01

    For further pushing ahead with the development of China's logistics industry, the author, based on the status quo of China's logistics industry, affirms the achievements made in the development course of the industry of China. By studying various respects of the industry including the understanding of logistics, standards of technical terms, logistics technologies and management, the author analyzes the major problems existence in China's current logistics industry and puts forward the rationalization proposal.

  13. Two-parameter quantum affine algebra of type G{sub 2}{sup (1)}, Drinfeld realization and vertex representation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yun, E-mail: ygao@yorku.ca [Department of Mathematics and Statistics, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3 (Canada); Hu, Naihong, E-mail: nhhu@math.ecnu.edu.cn [Department of Mathematics, East China Normal University, Shanghai 200241 (China); Zhang, Honglian, E-mail: hlzhangmath@shu.edu.cn [Department of Mathematics, Shanghai University, Shanghai 200444 (China)

    2015-01-15

    In this paper, we define the two-parameter quantum affine algebra for type G{sub 2}{sup (1)} and give the (r, s)-Drinfeld realization of U{sub r,s}(G{sub 2}{sup (1)}), as well as establish and prove its Drinfeld isomorphism. We construct and verify explicitly the level-one vertex representation of two-parameter quantum affine algebra U{sub r,s}(G{sub 2}{sup (1)}), which also supports an evidence in nontwisted type G{sub 2}{sup (1)} for the uniform defining approach via the two-parameter τ-invariant generating functions proposed in Hu and Zhang [Generating functions with τ-invariance and vertex representations of two-parameter quantum affine algebras U{sub r,s}(g{sup ^}): Simply laced cases e-print http://arxiv.org/abs/1401.4925 ].

  14. The Role of Item Models in Automatic Item Generation

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis

    2012-01-01

    Automatic item generation represents a relatively new but rapidly evolving research area where cognitive and psychometric theories are used to produce tests that include items generated using computer technology. Automatic item generation requires two steps. First, test development specialists create item models, which are comparable to templates…

  15. On two-parameter models of photon cross sections: application to dual-energy CT imaging.

    Science.gov (United States)

    Williamson, Jeffrey F; Li, Sicong; Devic, Slobodan; Whiting, Bruce R; Lerma, Fritz A

    2006-11-01

    The goal of this study is to evaluate the theoretically achievable accuracy in estimating photon cross sections at low energies (20-1000 keV) from idealized dual-energy x-ray computed tomography (CT) images. Cross-section estimation from dual-energy measurements requires a model that can accurately represent photon cross sections of any biological material as a function of energy by specifying only two characteristic parameters of the underlying material, e.g., effective atomic number and density. This paper evaluates the accuracy of two commonly used two-parameter cross-section models for postprocessing idealized measurements derived from dual-energy CT images. The parametric fit model (PFM) accounts for electron-binding effects and photoelectric absorption by power functions in atomic number and energy and scattering by the Klein-Nishina cross section. The basis-vector model (BVM) assumes that attenuation coefficients of any biological substance can be approximated by a linear combination of mass attenuation coefficients of two dissimilar basis substances. Both PFM and BVM were fit to a modern cross-section library for a range of elements and mixtures representative of naturally occurring biological materials (Z = 2-20). The PFM model, in conjunction with the effective atomic number approximation, yields estimated the total linear cross-section estimates with mean absolute and maximum error ranges of 0.6%-2.2% and 1%-6%, respectively. The corresponding error ranges for BVM estimates were 0.02%-0.15% and 0.1%-0.5%. However, for photoelectric absorption frequency, the PFM absolute mean and maximum errors were 10.8%-22.4% and 29%-50%, compared with corresponding BVM errors of 0.4%-11.3% and 0.5%-17.0%, respectively. Both models were found to exhibit similar sensitivities to image-intensity measurement uncertainties. Of the two models, BVM is the most promising approach for realizing dual-energy CT cross-section measurement.

  16. Transformation - Revolution in Military Logistics

    Science.gov (United States)

    2007-11-02

    adopted by the logistics community as part of the Army’s Revolution in Military Logistics ....operations." To support this vision, Army logistics requires a quantum leap in strategic responsiveness. This change is called "Revolution in Military ... Logistics ," to know what the customer, the Warfighter, needs before he requests it. This study examines proposed improvements in automation

  17. Logistics costs of the enterprise

    Directory of Open Access Journals (Sweden)

    Andrea Rosová

    2007-06-01

    Full Text Available The article describe a problem of specification and systematization of enterprise’s logistics costs. With in a growing division of labour, also logistics costs increase their part in enterprises total costs.Almost all decisions about products and production in general, influence logistics processes even logistics costs and performances.In present is not clear enough, which of the cost-particles are relevant fot logistics costs, because some of logistics cost-particles accounts within overhead are charged together with costs of other sorts.Substantive step in the process of the monitoring and evidence of logistics costs is definition of this, that costs of enterprise´s processes will be inclusive in logistics costs and determining points of contact with the others departments (acquisition, production, sale etc.. After the specification of meditation processes, there is a need to choose applicable parameters for the expression of logistics performances. Besides logistics costs is needed to know logistics performances equivalent herewith at a cost of, therefore from the control side have for enterprise bigger value indices expressive correlation costs and performances(e.g. share of logistics unit costs performance.At the proposal and evidence of logistics costs and performances is needed consistently entertain an individual conditions of enterprise. Because the area of processes included strongly affects the size of account logistics costs and its share part in total costs of enterprise. Logistics costs are flow line between economy and logistics of the enterprise.

  18. Olympic Effect on Beijing Logistics

    Institute of Scientific and Technical Information of China (English)

    Guo Liqin

    2008-01-01

    @@ Olympic logistics network as preparationIn 2003, the Beijing municipal government proposed the blueprint for three key logistics projects for the 2008 Olympics. It planned to build three logistics bases (at Yancun in Fangshan District, Majuqiao in Tongzhou, and Shahe in Changping District) along with four logistics centers (at Tianzhu in Chaoyang, Shibajiadian in Chaoyang, Dazhuang in Daxing, and Mentougou).

  19. SHIPPING OF RADIOACTIVE ITEMS

    CERN Multimedia

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate and massive objects require a longer procedure and will therefore take longer.

  20. [Understanding logistic regression].

    Science.gov (United States)

    El Sanharawi, M; Naudet, F

    2013-10-01

    Logistic regression is one of the most common multivariate analysis models utilized in epidemiology. It allows the measurement of the association between the occurrence of an event (qualitative dependent variable) and factors susceptible to influence it (explicative variables). The choice of explicative variables that should be included in the logistic regression model is based on prior knowledge of the disease physiopathology and the statistical association between the variable and the event, as measured by the odds ratio. The main steps for the procedure, the conditions of application, and the essential tools for its interpretation are discussed concisely. We also discuss the importance of the choice of variables that must be included and retained in the regression model in order to avoid the omission of important confounding factors. Finally, by way of illustration, we provide an example from the literature, which should help the reader test his or her knowledge.

  1. Logistics innovation development

    DEFF Research Database (Denmark)

    Pedrosa, Alex; Blazevic, Vera; Jasmand, Claudia

    2015-01-01

    limitations/implications – In general, this paper contributes to the understanding of the individuals’ behaviors underlying organization-level phenomena, such as logistics service providers’ customer knowledge acquisition. Practical implications – Findings illustrate that BSEs are well advised to concentrate...... and broaden their knowledge about customers for the development of innovations. Design/methodology/approach – Qualitative research based on multiple semi-structured interviews with BSEs of six logistics service providers was conducted to explore the deepening and broadening of customer knowledge during...... development process. Yet, the specific sequence depends on the type of innovation developed (customized vs standardized). Customer knowledge tends to be deepened in one-on-one interactions, while knowledge tends to be broadened in interactions with numerous and diverse customer firm members. Research...

  2. Error Variance of Rasch Measurement with Logistic Ability Distributions.

    Science.gov (United States)

    Dimitrov, Dimiter M.

    Exact formulas for classical error variance are provided for Rasch measurement with logistic distributions. An approximation formula with the normal ability distribution is also provided. With the proposed formulas, the additive contribution of individual items to the population error variance can be determined without knowledge of the other test…

  3. Item Banking with Embedded Standards

    Science.gov (United States)

    MacCann, Robert G.; Stanley, Gordon

    2009-01-01

    An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how…

  4. Item Banking with Embedded Standards

    Science.gov (United States)

    MacCann, Robert G.; Stanley, Gordon

    2009-01-01

    An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how…

  5. Humanitarian logistics and sustainability

    CERN Document Server

    Leeuw, Sander; Regattieri, Alberto; Souza, Robert

    2015-01-01

    This contributed volume combines conceptual and strategic research articles dealing with the "why" and "to what end" of sustainable operations in humanitarian logistics, as well as operational research contributions regarding the "how" from the United Nations as well as from researchers and organizations from different countries (Germany, Australia, Singapore, Italy, Denmark, Jordan). The target audience primarily comprises research experts, decision makers  and practitioners in the field, but the book may also be beneficial for graduate students.

  6. Logistics Assessment Guidebook

    Science.gov (United States)

    2011-07-01

    significant. Another case involved the integration of an aircraft and ground vehicle system. Integration issues were identified early in the design...for height and width; insufficient power requirements to support maintenance actions; and insufficient design of the autonomic logistics system...evaluation at IOT &E and thus on track for Initial Operational Capability (IOC). If not, a plan is in place to ensure they are met (ref DoDI 5000; CJCSM

  7. Rise of humanitarian logistics

    CSIR Research Space (South Africa)

    Maspero, EL

    2008-07-01

    Full Text Available ethical debates raged for both sides. This further complicated a complex supply chain as aid already in the pipeline was halted and returned. After extensive negotiations between the humanitarian sector and the national governments in each country... and financial cost (Tomasini & Van Wassenhove, 2005). 3. COMPARING THE HUMANITARIAN SUPPLY CHAIN TO A COMMERCIAL ONE Anyisa Thomas, Executive Director of the Fritz Institute is quoted by Rodman (2004) as saying: “humanitarian logistics has much in common...

  8. Role of logistics centres in national logistics system

    Directory of Open Access Journals (Sweden)

    2010-06-01

    Full Text Available This article presents a division of logistics centres according to various criteria and specifies their role in a national logistics system. It provides a classification of the main logistics network nodes. It also describes those features of logistics centres that have an impact on zoning development of towns and regions. The current situation in the national logistics system has been presented here against theoretical analyses and also a concept for the development of a logistics centre network in Poland has been formulated.

  9. A Multidimensional Partial Credit Model with Associated Item and Test Statistics: An Application to Mixed-Format Tests

    Science.gov (United States)

    Yao, Lihua; Schwarz, Richard D.

    2006-01-01

    Multidimensional item response theory (IRT) models have been proposed for better understanding the dimensional structure of data or to define diagnostic profiles of student learning. A compensatory multidimensional two-parameter partial credit model (M-2PPC) for constructed-response items is presented that is a generalization of those proposed to…

  10. Logistic innovations in transport

    Directory of Open Access Journals (Sweden)

    Mirosław Antonowicz

    2014-03-01

    Full Text Available Introduction: The article discusses the issue of logistic innovations in transport. The essentials of logistic innovations in transport together with some examples of specific innovations are presented. The role of the client's needs in transport innovations is indicated. The most vital postulates affecting the innovativeness of shipping companies and derived from the author's experience as well as scholarly publications, are time, safety, reliability as well as comprehensiveness of service offer. Following the analysis of the issue, and on the grounds of Kaizen's and Lean's method, the concept of continuous innovations is suggested as very useful for the development of transport. The potential of clusters as the source of logistic innovations in transport is emphasised. Methods: The discussion of the issue was preceded by the author's analysis of written sources on innovativeness, the evaluation of ratings of innovativeness as well as the analysis of rewarded innovative solutions in transport subsequent to the businesses participation in the programme of innovative solutions in transport. The role of innovation practical business operations is argued following the analysis of some strategic documents such as: 2011 White Paper and the Strategy for the Development of Transport by 2020 adopted by the Polish government in 2013. Aim: The aim of the article is to present the role and significance of the issue of logistic innovations in transport and to cite instances of practical solutions implemented by shipping companies, the solutions which resulted in measurable effects. Following the author's observation of the instances of innovative solutions as well as his analysis of the ratings of innovativeness, the article aims to present the conclusions as for the specific kinds of activities which are indispensable to foster innovativeness in transport. Conclusions: The conclusions derived from the author's analyses and observations show that logistic

  11. Typology of Logistics Curricula – Four Categories of Logistics of Logistics Undergraduate Education in Europe

    OpenAIRE

    Tarvo Niine; Ott Koppel

    2015-01-01

    The field of logistics education is rather colorful. The range of possible topics is huge and so each curriculum has unique approach towards which topic areas to emphasize and which to treat briefly or even omit. There is only little effective standardization in logistics education. This study examines the content of 42 undergraduate logistics curricula in Europe via cluster analysis, with a goal to propose a typology of logistics curricula. The findings define the spectrum of logistics educa...

  12. Exploring Crossing Differential Item Functioning by Gender in Mathematics Assessment

    Science.gov (United States)

    Ong, Yoke Mooi; Williams, Julian; Lamprianou, Iasonas

    2015-01-01

    The purpose of this article is to explore crossing differential item functioning (DIF) in a test drawn from a national examination of mathematics for 11-year-old pupils in England. An empirical dataset was analyzed to explore DIF by gender in a mathematics assessment. A two-step process involving the logistic regression (LR) procedure for…

  13. Relationships between the Thurstone and Rasch Approaches to Item Scaling.

    Science.gov (United States)

    Andrich, David

    1978-01-01

    When the logistic function is substituted for the normal, Thurstone's Case V specialization of the law of comparative judgment for paired comparison responses gives an identical equation for the estimation of item scale values, as does the Rasch formulation for direct responses. Comparisons are made. (Author/CTM)

  14. Differential Item Functioning on Two Tests of EFL Proficiency.

    Science.gov (United States)

    Ryan, Katherine E.; Bachman, Lyle F.

    1992-01-01

    The extent to which items from the Test of English as a Foreign Language and the First Certificate in English function differently for test-takers of equal ability from different native language and curricular backgrounds was investigated. Results suggest a need for methods like logistic regression to examine nonuniform differential item…

  15. Defense Logistics: Improvements Needed to Accurately Assess the Performance of DOD’s Materiel Distribution Pipeline

    Science.gov (United States)

    2015-02-01

    Logistics materiel owned by the unit and brought from the home station; delivering sustainment items, which are supplies such as food , water...the local retail supply system, the unit will then place a new request with the wholesale supply system. Similar to logistics response time, customer...standard that 85 percent of all items ordered from the United States for delivery to Japan by ocean transport should be delivered within 57 days

  16. SHIPPING OF RADIOACTIVE ITEMS

    CERN Multimedia

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate, preparation of the package and related paperwork). Large and massive objects require a longer procedure and will therefore take longer.

  17. Mechanical Parking System Logistics

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As the number of motor vehicles increases rapidly in many populated countries, t he shortage of parking space has become a difficult problem to all cities around the world. The contradiction between the shortage of parking space and the incr easing number of motor vehicles is still growing in the recent years. The utiliz ation of various kinds of mechanical parking facilities is an effective solution to this problem. How to organize a reasonable logistics system in a mechanical parking lot so that as man...

  18. Saturated logistic avalanche model

    Science.gov (United States)

    Aielli, G.; Camarri, P.; Cardarelli, R.; Di Ciaccio, A.; Liberti, B.; Paoloni, A.; Santonico, R.

    2003-08-01

    The search for an adequate avalanche RPC working model evidenced that the simple exponential growth can describe the electron multiplication phenomena in the gas with acceptable accuracy until the external electric field is not perturbed by the growing avalanche. We present here a model in which the saturated growth induced by the space charge effects is explained in a natural way by a constant coefficient non-linear differential equation, the Logistic equation, which was originally introduced to describe the evolution of a biological population in a limited resources environment. The RPCs, due to the uniform and intense field, proved to be an ideal device to test experimentally the presented model.

  19. On two-parameter equations of state and the limitations of a hard sphere Peng-Robinson equation

    Science.gov (United States)

    Harmens, A.; Jeremiah, Dawn E.

    Simple two-parameter equations of state are exceptionally effective for calculations on systems of small, uncomplicated molecules. They are therefore extremely useful for vapour-liquid equilibrium calculations in cryogenic and light hydrocarbon process design. In a search for further improvement three two-parameter equations of state with a co-volume repulsion term and three with a hard sphere repulsion term have been investigated. Their characteristic constants at the critical point have been compared. The procedure for fitting the two parameters to empirical data in the subcritical region was analysed. A perturbed hard sphere equation with a Peng-Robinson attraction term was shown to be unsuitable for application over a wide range of p, T conditions. A similar equation with a Redlich-Kwong attraction term gives good service in the cryogenic range.

  20. Entanglement for a two-parameter class of states in a high-dimension bipartite quantum system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The entanglement for a two-parameter class of states in a high-dimension (m  n,n≥m≥3) bipartite quantum system is discussed.The negativity (N) and the relative entropy of entanglement (Er) are calculated,and the analytic expressions are obtained.Finally the relation between the negativity and the relative entropy of entanglement is discussed.The result demonstrates that all PPT states of the two-parameter class of states are separable,and all entangled states are NPT states.Different from the 2 ? n quantum system,the negativity for a two-parameter class of states in high dimension is not always greater than or equal to the relative entropy of entanglement.The more general relation expression is mN/2≥Er.

  1. Logistics systems optimization under competition

    DEFF Research Database (Denmark)

    Choi, Tsan Ming; Govindan, Kannan; Ma, Lijun

    2015-01-01

    Nowadays, optimization on logistics and supply chain systems is a crucial and critical issue in industrial and systems engineering. Important areas of logistics and supply chain systems include transportation control, inventory management, and facility location planning. Under a competitive market...

  2. Outsourcing Operational Logistics: Buyer Beware

    Science.gov (United States)

    2006-05-31

    Privatized Military Logistics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON Chairman, JMO Dept...CONTENTS Abstract i Introduction 1 Historical Examples of Privatized Military Logistics 2 Analysis: Problems of Outsourcing Military Logistics 5...to combat operations contribute to the argument not to privatize military logistics . 2 In the current vocabulary of the American military

  3. Control Systems for Logistics Performance

    OpenAIRE

    Virolainen, V.-M.

    1991-01-01

    This text is concerned with identifying and outlining the various aspects of logistics control and performance measurement process. The objective is to identify, based on available literature, methods and techniques which can be used to measure the performance of logistics. Logistics management is essentially a task of balancing between minimizing cost and ensuring availability objectives. Availability can be seen as the output of logistics system. On the input side, management is concer...

  4. LOGISTICS IN KNOWLEDGE BASED ECONOMY

    OpenAIRE

    Stefan NEDELEA

    2013-01-01

    In the context of contemporary economy logistics changes refer to the emergence of new inter-organizational logistics structures such as logistics networks, and to a number of alterations in organizations’ vision and conduct regarding the role and importance of knowledge. The research focuses on identifying the instruments promoting inter-organizational knowledge transfer within logistics networks provided that each organization relies on its own knowledge and organizational skills to ensure ...

  5. LOGISTICS - SOURCE OF COMPETITIVE ADVANTAGE

    OpenAIRE

    Adriana SCRIOSTEANU; Popescu, Daniela

    2014-01-01

    This paper presents the logistics if source of competitive advantage. Logistics can offer a source of competitive advantage, such as a superior position compared to the competitors regarding cost reductions, service diversity and satisfaction of consumer requirements. The logistic activities generate cost and give value to the final product .Despite that the same logistic activity can be done in many ways, with different costs and performance , the evaluation of the activities and the links b...

  6. Control Systems for Logistics Performance

    OpenAIRE

    Virolainen, V.-M.

    1991-01-01

    This text is concerned with identifying and outlining the various aspects of logistics control and performance measurement process. The objective is to identify, based on available literature, methods and techniques which can be used to measure the performance of logistics. Logistics management is essentially a task of balancing between minimizing cost and ensuring availability objectives. Availability can be seen as the output of logistics system. On the input side, management is concer...

  7. Possibilities of Logistics Policy Improvement

    OpenAIRE

    Petr Průša; David Tilkeridis

    2009-01-01

    The paper presents the strategic logistics management with emphasis on clear, accurate and effective material flow from the suppliers and internally, as well as an outline of the logistics policy for continuous improvement. The implementation of a complete Supplier Logistics Performance System is essential to support internal processes efficiency and establish a continuous improvement system according to the main logistics policy. Every company should consider such a system in order to win in...

  8. LOGISTICS IN KNOWLEDGE BASED ECONOMY

    OpenAIRE

    Stefan NEDELEA

    2013-01-01

    In the context of contemporary economy logistics changes refer to the emergence of new inter-organizational logistics structures such as logistics networks, and to a number of alterations in organizations’ vision and conduct regarding the role and importance of knowledge. The research focuses on identifying the instruments promoting inter-organizational knowledge transfer within logistics networks provided that each organization relies on its own knowledge and organizational skills to ensure ...

  9. The Road to Focused Logistics

    Science.gov (United States)

    2001-04-10

    The Revolution in Military Logistics (RML) and Focused Logistics requires us to view sustainment needs and requirements in a new perspective. Gone...has taken the tenets of Force XXI, Battlefield Distribution, Velocity Management, Army After Next, and the Revolution In Military Logistics and fused

  10. Faculty development on item writing substantially improves item quality.

    NARCIS (Netherlands)

    Naeem, N.; Vleuten, C.P.M. van der; Alfaris, E.A.

    2012-01-01

    The quality of items written for in-house examinations in medical schools remains a cause of concern. Several faculty development programs are aimed at improving faculty's item writing skills. The purpose of this study was to evaluate the effectiveness of a faculty development program in item develo

  11. IRT Item Parameter Scaling for Developing New Item Pools

    Science.gov (United States)

    Kang, Hyeon-Ah; Lu, Ying; Chang, Hua-Hua

    2017-01-01

    Increasing use of item pools in large-scale educational assessments calls for an appropriate scaling procedure to achieve a common metric among field-tested items. The present study examines scaling procedures for developing a new item pool under a spiraled block linking design. The three scaling procedures are considered: (a) concurrent…

  12. Comparison of IRT Likelihood Ratio Test and Logistic Regression DIF Detection Procedures

    Science.gov (United States)

    Atar, Burcu; Kamata, Akihito

    2011-01-01

    The Type I error rates and the power of IRT likelihood ratio test and cumulative logit ordinal logistic regression procedures in detecting differential item functioning (DIF) for polytomously scored items were investigated in this Monte Carlo simulation study. For this purpose, 54 simulation conditions (combinations of 3 sample sizes, 2 sample…

  13. Odds Ratio, Delta, ETS Classification, and Standardization Measures of DIF Magnitude for Binary Logistic Regression

    Science.gov (United States)

    Monahan, Patrick O.; McHorney, Colleen A.; Stump, Timothy E.; Perkins, Anthony J.

    2007-01-01

    Previous methodological and applied studies that used binary logistic regression (LR) for detection of differential item functioning (DIF) in dichotomously scored items either did not report an effect size or did not employ several useful measures of DIF magnitude derived from the LR model. Equations are provided for these effect size indices.…

  14. Comparison of IRT Likelihood Ratio Test and Logistic Regression DIF Detection Procedures

    Science.gov (United States)

    Atar, Burcu; Kamata, Akihito

    2011-01-01

    The Type I error rates and the power of IRT likelihood ratio test and cumulative logit ordinal logistic regression procedures in detecting differential item functioning (DIF) for polytomously scored items were investigated in this Monte Carlo simulation study. For this purpose, 54 simulation conditions (combinations of 3 sample sizes, 2 sample…

  15. A two-parameter family of exact asymptotically flat solutions to the Einstein-scalar field equations

    Energy Technology Data Exchange (ETDEWEB)

    Nikonov, V V; Tchemarina, Ju V; Tsirulev, A N [Department of Mathematics, Tver State University, Sadovyi per. 35, Tver 170002 (Russian Federation)], E-mail: tsirulev@tversu.ru

    2008-07-07

    We consider a static spherically symmetric real scalar field, minimally coupled to Einstein gravity. A two-parameter family of exact asymptotically flat solutions is obtained by using the inverse problem method. This family includes non-singular solutions, black holes and naked singularities. For each of these solutions the respective potential is partially negative but positive near spatial infinity. (comments, replies and notes)

  16. ON SHARP MARKOV PROPERTY OF TWO-PARAMETER MARKOV PROCESSES%两参数Markov过程的Sharp Markov性

    Institute of Scientific and Technical Information of China (English)

    陈雄

    2011-01-01

    It is proven that for two-parameter Markov processes, only when they are the finite or countable unions of rectangles, will they show Sharp Markov property.%证明了两参数Markov过程仅在正位矩形的有限并或可列并区域上才具有Sharp Markov性.

  17. Reducing Mission Logistics with Multipurpose Cargo Transfer Bags

    Science.gov (United States)

    Baccus, Shelley; Broyan, James Lee, Jr.; Borrego, Melissa

    2016-01-01

    The Logistics Reduction (LR) project within Advanced Exploration Systems (AES) is tasked with reducing logistical mass and repurposing logistical items. Multipurpose Cargo Transfer Bags (MCTB) have been designed such that they can serve the same purpose as a Cargo Transfer Bag (CTB), the common logistics carrying bag for the International Space Station (ISS). After use as a cargo carrier, a regular CTB becomes trash, whereas the MCTB can be unfolded into a flat panel for reuse. Concepts and potential benefits for various MCTB applications will be discussed including partitions, crew quarters, solar radiation storm shelters, acoustic blankets, and forward osmosis water processing. Acoustic MCTBs are currently in use on ISS to reduce the noise generated by the T2 treadmill, which reaches the hazard limit at high speeds. The development of the AMCTB included identification of keep-out zones, acoustic properties, deployment considerations, and structural testing. Features developed for these considerations are applicable to MCTBs for all crew outfitting applications.

  18. Multipurpose Cargo Transfer Bags fro Reducing Exploration Mission Logistics

    Science.gov (United States)

    Baccus, Shelley; Broyan, James Lee, Jr.; Borrego, Melissa

    2016-01-01

    The Logistics Reduction (LR) project within the Advanced Exploration Systems (AES) division is tasked with reducing logistical mass and repurposing logistical items. Multipurpose Cargo Transfer Bags (MCTB) have been designed such that they can serve the same purpose as a Cargo Transfer Bag (CTB), the common logistics carrying bag for the International Space Station (ISS). After use as a cargo carrier, a regular CTB becomes trash, whereas the MCTB can be unfolded into a flat panel for reuse. Concepts and potential benefits for various MCTB applications will be discussed including partitions, crew quarters, solar radiation storm shelters, acoustic blankets, and forward osmosis water processing. Acoustic MCTBs are currently in use on ISS to reduce the noise generated by the T2 treadmill, which reaches the hazard limit at high speeds. The development of the AMCTB included identification of keep out zones, acoustic properties, deployment considerations, and structural testing. Features developed for these considerations are applicable to MCTBs for all crew outfitting applications.

  19. NASA Advanced Explorations Systems: Concepts for Logistics to Living

    Science.gov (United States)

    Shull, Sarah A.; Howe, A. Scott; Flynn, Michael T.; Howard, Robert

    2012-01-01

    The NASA Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) project strives to enable a largely mission-independent cradle-to-grave-to-cradle approach to minimize logistics contributions to total mission architecture mass. The goals are to engineer logistics materials, common crew consumables, and container configurations to meet the following five basic goals: 1. Minimize intrinsic logistics mass and improve ground logistics flexibility. 2. Allow logistics components to be directly repurposed for on-orbit non-logistics functions (e.g., crew cabin outfitting) thereby indirectly reducing mass/volume. 3. Compact and process logistics that have not been directly repurposed to generate useful on-orbit components and/or compounds (e.g., radiation shielding, propellant, other usable chemical constituents). 4. Enable long-term stable storage and disposal of logistics end products that cannot be reused or repurposed (e.g., compaction for volume reduction, odor control, and maintenance of crew cabin hygienic conditions). 5. Allow vehicles in different mission phases to share logistics resources. This paper addresses the work being done to meet the second goal, the direct repurposing of logistics components to meet other on-orbit needs, through a strategy termed Logistics to Living (L2L). L2L has several areas but can be defined as repurposing or converting logistical items (bags, containers, foam, components, etc.) into useful crew items or life support augmentation on-orbit after they have provided their primary logistics function. The intent is that by repurposing items, dedicated crew items do not have to be launched and overall launch mass is decreased. For non-LEO missions, the vehicle interior volume will be relatively fixed so L2L will enable this volume to be used more effectively through reuse and rearrangement of logistical components. Past work in the area of L2L has already conceptually developed several potential technologies [Howe

  20. Item Overexposure in Computerized Classification Tests Using Sequential Item Selection

    Directory of Open Access Journals (Sweden)

    Alan Huebner

    2012-06-01

    Full Text Available Computerized classification tests (CCTs often use sequential item selection which administers items according to maximizing psychometric information at a cut point demarcating passing and failing scores. This paper illustrates why this method of item selection leads to the overexposure of a significant number of items, and the performances of three different methods for controlling maximum item exposure rates in CCTs are compared. Specifically, the Sympson-Hetter, restricted, and item eligibility methods are examined in two studies realistically simulating different types of CCTs and are evaluated based upon criteria including classification accuracy, the number of items exceeding the desired maximum exposure rate, and test overlap. The pros and cons of each method are discussed from a practical perspective.

  1. Framework of the DOD Logistics System: Educating Leaders on Logistics

    Science.gov (United States)

    2002-04-01

    way to learn the business. I chose this topic for research because I wanted to maximize my opportunity to learn about military logistics during my...Through my exploration of military logistics , I wanted to ultimately develop a better cognitive �big- picture� view of Department of Defense (DOD...successes of the future may be delayed indefinitely.�4 Principles are the basic truths of military logistics hard learned from past experiences

  2. Typology of Logistics Curricula – Four Categories of Logistics of Logistics Undergraduate Education in Europe

    Directory of Open Access Journals (Sweden)

    Tarvo Niine

    2015-05-01

    Full Text Available The field of logistics education is rather colorful. The range of possible topics is huge and so each curriculum has unique approach towards which topic areas to emphasize and which to treat briefly or even omit. There is only little effective standardization in logistics education. This study examines the content of 42 undergraduate logistics curricula in Europe via cluster analysis, with a goal to propose a typology of logistics curricula. The findings define the spectrum of logistics education in four clusters, ranging from „business administration“ with little focus on most specific logistics topics, through „interdisciplinary logistics management“ and „modern transport management“ to „logistics engineering“ with a strong quantitative and technology approach. However, a problem remains that curriculum title does not always reflect actual profile. A typical title “logistics management” might in one case contain various engineering elements, but in another none at all. Such findings point out the need for curricula boards to decide, if trying to cover the entire scope by „one-size-fits-all“ program is the best option or if more distinct focus is needed. In both cases this decision needs to be intentional, agreed and clearly communicated to avoid confusing students and society. Furthermore, the study points out the need to refine standards of competences in logistics, especially for logistics engineering.

  3. The Rasch Model for Dichotomous Items: Theory, Applications and a Computer Program. No. 63.

    Science.gov (United States)

    Gustafsson, Jan-Eric

    The Rasch model for test analysis is described and compared with two-parameter and three-parameter latent-trait models. Conditional maximum likelihood equations for estimating item parameters are derived, and estimates of person parameters are described together with their confidence intervals. Goodness of fit tests are discussed, including a…

  4. Analysis of logistic process : Measuring performance using balanced score card

    OpenAIRE

    Kamthunzi, Eleanor

    2014-01-01

    All industrial companies want to be productive and to make profit as well as expand their markets. To accomplish this, organizations are working on different principles, strategies to improve their processes to achieve their goals to have the right item in the right quantity at the right place, in the right condition to the right customer at the right time. This is where logistics management comes in, to make this all possible. This thesis aims at looking into logistics as a process to sh...

  5. Development and community-based validation of eight item banks to assess mental health.

    Science.gov (United States)

    Batterham, Philip J; Sunderland, Matthew; Carragher, Natacha; Calear, Alison L

    2016-09-30

    There is a need for precise but brief screening of mental health problems in a range of settings. The development of item banks to assess depression and anxiety has resulted in new adaptive and static screeners that accurately assess severity of symptoms. However, expansion to a wider array of mental health problems is required. The current study developed item banks for eight mental health problems: social anxiety disorder, panic disorder, post-traumatic stress disorder, obsessive-compulsive disorder, adult attention-deficit hyperactivity disorder, drug use, psychosis and suicidality. The item banks were calibrated in a population-based Australian adult sample (N=3175) by administering large item pools (45-75 items) and excluding items on the basis of local dependence or measurement non-invariance. Item Response Theory parameters were estimated for each item bank using a two-parameter graded response model. Each bank consisted of 19-47 items, demonstrating excellent fit and precision across a range of -1 to 3 standard deviations from the mean. No previous study has developed such a broad range of mental health item banks. The calibrated item banks will form the basis of a new system of static and adaptive measures to screen for a broad array of mental health problems in the community.

  6. An Overview of Reverse Logistics

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-xiang; HE Xin

    2005-01-01

    Until recently, investment in logistics has focused mainly on the flows from companies to markets. Growing concerns for the environment and conserving resources have created new logistical approaches to more effectively manage the distribution function, and make better use of the resources available to an organization. One such approach is reverse logistics, which uses various methods to give scope for a back-load of finished products, components, waste, reusable packing, etc. from consumer to manufacturer. Back-loads allow manufacturers to reduce costs by using the distribution vehicle's return journey to create income or added value. This basic concept is now being developed to create novel solutions to the problems of reducing pollution, costs and vehicle movements, whilst maintaining high customer service levels. In this paper, the idea of reverse logistics is presented; motivations for it are analyzed, several successful practices are demonstrated and some important truths regarding successful reverse logistics are identified, trend of reverse logistics is provided.

  7. The Emergence of City Logistics

    DEFF Research Database (Denmark)

    Gammelgaard, Britta

    2015-01-01

    Purpose: – Many city logistics projects in Europe have failed. A better understanding of the complex organizational change processes in city logistics projects with many stakeholders may expand city logistics capabilities and thereby help prevent future failures. The purpose of this paper...... is therefore to increase understanding of how city logistics emerge, and secondarily, to investigate whether such processes can be managed at all. Design/methodology/approach: – A paradigm shift in urban planning creates new ways of involving stakeholders in new sustainability measures such as city logistics....... Organizational change theory is applied to capture the social processes leading to emergence of city logistics. The methodology is a qualitative processual analysis of a single longitudinal case. Findings: – The change process took different forms over time. At the time of concluding the analysis, positive...

  8. The Emergence of City Logistics

    DEFF Research Database (Denmark)

    2014-01-01

    Purpose: Many city logistics projects in Europe have failed. The purpose of this article is to increase understanding of how city logistics emerge. A better understanding of the complex organizational processes with many actors and stakeholders in city logistics projects may prevent further...... failures. Design/methodology/approach: Theory on organizational change is applied to capture the processes leading to emergence of city logistics. The methodology is process analysis on a single longitudinal case. Findings: The emergence of the Copenhagen city logistics project can be understood....... The study aims at understanding the social processes towards reduced congestion and greenhouse gas emissions from goods transport in inner cities. Originality/value: By better understanding the organization processes leading to implementation of city logistics, other projects in other cities may learn from...

  9. An alternative factorization of the quantum harmonic oscillator and two-parameter family of self-adjoint operators

    Energy Technology Data Exchange (ETDEWEB)

    Arcos-Olalla, Rafael, E-mail: olalla@fisica.ugto.mx [Departamento de Física, DCI Campus León, Universidad de Guanajuato, Apdo. Postal E143, 37150 León, Gto. (Mexico); Reyes, Marco A., E-mail: marco@fisica.ugto.mx [Departamento de Física, DCI Campus León, Universidad de Guanajuato, Apdo. Postal E143, 37150 León, Gto. (Mexico); Rosu, Haret C., E-mail: hcr@ipicyt.edu.mx [IPICYT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Apdo. Postal 3-74 Tangamanga, 78231 San Luis Potosí, S.L.P. (Mexico)

    2012-10-01

    We introduce an alternative factorization of the Hamiltonian of the quantum harmonic oscillator which leads to a two-parameter self-adjoint operator from which the standard harmonic oscillator, the one-parameter oscillators introduced by Mielnik, and the Hermite operator are obtained in certain limits of the parameters. In addition, a single Bernoulli-type parameter factorization, which is different from the one introduced by M.A. Reyes, H.C. Rosu, and M.R. Gutiérrez [Phys. Lett. A 375 (2011) 2145], is briefly discussed in the final part of this work. -- Highlights: ► Factorizations with operators which are not mutually adjoint are presented. ► New two-parameter and one-parameter self-adjoint oscillator operators are introduced. ► Their eigenfunctions are two- and one-parameter deformed Hermite functions.

  10. 两个参数的新Hilbert型积分不等式%Hilbert-type Integral Inequality with Two Parameters

    Institute of Scientific and Technical Information of China (English)

    付向红

    2011-01-01

    By introducing the weight function,we obtain a Hilbert-type integral inequality with two parameters and the equivalent form with a best constant factor.%通过引入权函数的方法,利用带权的H lder不等式,得到一个带两个参数的并具有最佳常数的新Hilbert型积分不等式及其等价形式.

  11. Two-Parameter Stochastic Resonance in a Model of Electrodissolution of Fe in H2SO4

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Stochastic resonance (SR) is shown in a two-parameter system, a model of electrodissolution of Fe in H2SO4. Modulation of two different parameters by a periodic signal in one parameter and noise in the other parameter is found to give rise to SR. The result indicates that the noise can enlarge a weak periodic signal and lead the system to order. The scenario and novel aspects of SR in this system are discussed.

  12. Situational Awareness and Logistics Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Situational Awareness and Logistics Division researches, develops, implements, and analyzes advanced systems to protect, enhance, and ensure resilienceof the...

  13. Bayesian item fit analysis for unidimensional item response theory models.

    Science.gov (United States)

    Sinharay, Sandip

    2006-11-01

    Assessing item fit for unidimensional item response theory models for dichotomous items has always been an issue of enormous interest, but there exists no unanimously agreed item fit diagnostic for these models, and hence there is room for further investigation of the area. This paper employs the posterior predictive model-checking method, a popular Bayesian model-checking tool, to examine item fit for the above-mentioned models. An item fit plot, comparing the observed and predicted proportion-correct scores of examinees with different raw scores, is suggested. This paper also suggests how to obtain posterior predictive p-values (which are natural Bayesian p-values) for the item fit statistics of Orlando and Thissen that summarize numerically the information in the above-mentioned item fit plots. A number of simulation studies and a real data application demonstrate the effectiveness of the suggested item fit diagnostics. The suggested techniques seem to have adequate power and reasonable Type I error rate, and psychometricians will find them promising.

  14. An item response theory analysis of the narcissistic personality inventory.

    Science.gov (United States)

    Ackerman, Robert A; Donnellan, M Brent; Robins, Richard W

    2012-01-01

    This research uses item response theory methods to evaluate the Narcissistic Personality Inventory (NPI; Raskin & Terry, 1988). Analyses using the 2-parameter logistic model were conducted on the total score and the Corry, Merritt, Mrug, and Pamp (2008) and Ackerman et al. (2011) subscales for the NPI. In addition to offering precise information about the psychometric properties of the NPI item pool, these analyses generated insights that can be used to develop new measures of the personality constructs embedded within this frequently used inventory.

  15. Logistics Integration: Closing the Gap

    Science.gov (United States)

    2012-05-18

    significant understanding of the relationship between operational planning elements on behalf of the operational planning team by the logistics planning...collaborative effort early and often throughout the planning and execution phases. This codependency has been rediscovered throughout history...now answer questions regarding force employment, major tasks and their sequencing, sustainment, and command relationships . Logistics requirements help

  16. Simulation Integrated Design for Logistics

    NARCIS (Netherlands)

    Veeke, H.P.M.

    2003-01-01

    The design of an innovative logistic system is a complex problem in the solution of which many disciplines are involved. Each discipline developed its own way of conceptual modeling for a logistic system based on a mono disciplinary perception. In essence this leads to a communication problem betwee

  17. Information Logistics Research report 2

    NARCIS (Netherlands)

    Willems, A.; Hajdasinski, A.K.; Willems, J.

    2009-01-01

    The goal of this research report is to further explore the concept of Information Logistics (IL), which refers to the usage and dispatch of information and methods of logistics able to support those processes. This report is based upon 6 questions that examine IL in organizations, healthcare organiz

  18. Logistic Regression: Concept and Application

    Science.gov (United States)

    Cokluk, Omay

    2010-01-01

    The main focus of logistic regression analysis is classification of individuals in different groups. The aim of the present study is to explain basic concepts and processes of binary logistic regression analysis intended to determine the combination of independent variables which best explain the membership in certain groups called dichotomous…

  19. INFORMATION STREAMS OF LOGISTICAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    E. N. Zhivitskaya

    2013-01-01

    Full Text Available The problem of formalisation and practical realisation of information streams of logistical systems, as the basic component of a separate kind of systems the logistical information systems having the features and properties that allows to investigate them by means of methods, applicable to information systems is considered.

  20. GRE Verbal Analogy Items: Examinee Reasoning on Items.

    Science.gov (United States)

    Duran, Richard P.; And Others

    Information about how Graduate Record Examination (GRE) examinees solve verbal analogy problems was obtained in this study through protocol analysis. High- and low-ability subjects who had recently taken the GRE General Test were asked to "think aloud" as they worked through eight analogy items. These items varied factorially on the…

  1. Classifying hospitals as mortality outliers: logistic versus hierarchical logistic models.

    Science.gov (United States)

    Alexandrescu, Roxana; Bottle, Alex; Jarman, Brian; Aylin, Paul

    2014-05-01

    The use of hierarchical logistic regression for provider profiling has been recommended due to the clustering of patients within hospitals, but has some associated difficulties. We assess changes in hospital outlier status based on standard logistic versus hierarchical logistic modelling of mortality. The study population consisted of all patients admitted to acute, non-specialist hospitals in England between 2007 and 2011 with a primary diagnosis of acute myocardial infarction, acute cerebrovascular disease or fracture of neck of femur or a primary procedure of coronary artery bypass graft or repair of abdominal aortic aneurysm. We compared standardised mortality ratios (SMRs) from non-hierarchical models with SMRs from hierarchical models, without and with shrinkage estimates of the predicted probabilities (Model 1 and Model 2). The SMRs from standard logistic and hierarchical models were highly statistically significantly correlated (r > 0.91, p = 0.01). More outliers were recorded in the standard logistic regression than hierarchical modelling only when using shrinkage estimates (Model 2): 21 hospitals (out of a cumulative number of 565 pairs of hospitals under study) changed from a low outlier and 8 hospitals changed from a high outlier based on the logistic regression to a not-an-outlier based on shrinkage estimates. Both standard logistic and hierarchical modelling have identified nearly the same hospitals as mortality outliers. The choice of methodological approach should, however, also consider whether the modelling aim is judgment or improvement, as shrinkage may be more appropriate for the former than the latter.

  2. Some Considerations about Low-Carbon Logistics

    Institute of Scientific and Technical Information of China (English)

    LI Yifan

    2013-01-01

    More and more People have paid attention to low-carbon logistics.This article,based on the characteristics of low-carbon logistics,proposes the effective ways to achieve low-carbon logistics,including logistics information,effective supply chain management,establishing environmental logistics and reverse logistics.

  3. A Mixed Effects Randomized Item Response Model

    Science.gov (United States)

    Fox, J.-P.; Wyrick, Cheryl

    2008-01-01

    The randomized response technique ensures that individual item responses, denoted as true item responses, are randomized before observing them and so-called randomized item responses are observed. A relationship is specified between randomized item response data and true item response data. True item response data are modeled with a (non)linear…

  4. Computerized adaptive testing with item cloning

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; van der Linden, Willem J.

    2003-01-01

    To increase the number of items available for adaptive testing and reduce the cost of item writing, the use of techniques of item cloning has been proposed. An important consequence of item cloning is possible variability between the item parameters. To deal with this variability, a multilevel item

  5. A Finite Element Study of the Bending Behavior of Beams Resting on Two-Parameter Elastic Foundation

    Directory of Open Access Journals (Sweden)

    Iancu-Bogdan Teodoru

    2006-01-01

    Full Text Available Although the Winkler’s model is a poor representation of the many practical subgrade or subbase materials, it is widely used in soil-structure problems for almost one and a half century. The foundations represented by Winkler model can not sustain shear stresses, and hence discontinuity of adjacent spring displacements can occur. This is the prime shortcoming of this foundation model which in practical applications may result in significant inaccuracies in the evaluated structural response. In order to overcome these problem many researchers have been proposed various mechanical foundation models considering interaction with the surroundings. Among them we shall mention the class of two-parameter foundations -- named like this because they have the second parameter which introduces interactions between adjacent springs, in addition to the first parameter from the ordinary Winkler’s model. This class of models includes Filonenko-Borodich, Pasternak, generalized, and Vlasov foundations. Mathematically, the equations to describe the reaction of the two-parameter foundations arc equilibrium ones, and the only difference is the definition of the parameters. For the convenience of discussion, the Pasternak foundation is adopted in present paper. In order to analyse the bending behavior of a Euler-Bernoulli beam resting on two-parameter elastic foundation a (displacement Finite Element (FE formulation, based on the cubic displacement function of the governing differential equation, is introduced. The resulting effects of shear stiffness of the Pasternak model on the mechanical quantities are discussed in comparison with those of the Winkler’s model. Some numerical case studies illustrate the accuracy of the formulation and the importance of the soil shearing effect in the vertical direction, associated with continuous elastic foundation.

  6. The Two-Parameter Brane Sigma-Model: M*, M' solutions and M-theory solutions dependent on exotic coordinates

    CERN Document Server

    Cook, Paul P

    2016-01-01

    We investigate two-parameter solutions of sigma-models on two dimensional symmetric spaces contained in E11. Embedding such sigma-model solutions in space-time gives solutions of M* and M'-theory where the metric depends on general travelling wave functions, as opposed to harmonic functions typical in general relativity, supergravity and M-theory. Weyl reflection allows such solutions to be mapped to M-theory solutions where the wave functions depend explicitly on extra coordinates contained in the fundamental representation of E11.

  7. Multiplexing technique using amplitude-modulated chirped fibre Bragg gratings with applications in two-parameter sensing

    Science.gov (United States)

    Wong, Allan C. L.; Childs, Paul A.; Peng, Gang-Ding

    2007-11-01

    A multiplexing technique using amplitude-modulated chirped fibre Bragg gratings (AMCFBGs) is presented. This technique realises the multiplexing of spectrally overlapped AMCFBGs with identical centre Bragg wavelength and bandwidth. Since it is fully compatible with the wavelength division multiplexing scheme, the number of gratings that can be multiplexed can be increased by several times. The discrete wavelet transform is used to demodulate such multiplexed signal. A wavelet denoising technique is applied to the multiplexed signal in conjunction with the demodulation. Strain measurements are performed to experimentally demonstrate the feasibility of this multiplexing technique. The absolute error and crosstalk are measured. An application to simultaneous two-parameter sensing is also demonstrated.

  8. Item Veto: Dangerous Constitutional Tinkering.

    Science.gov (United States)

    Bellamy, Calvin

    1989-01-01

    In theory, the item veto would empower the President to remove wasteful and unnecessary projects from legislation. Yet, despite its history at the state level, the item veto is a loosely defined concept that may not work well at the federal level. Much more worrisome is the impact on the balance of power. (Author/CH)

  9. Development of Regional Transport Logistics Terminal- Transport Logistics Approach

    Directory of Open Access Journals (Sweden)

    Peter Jenček

    2008-07-01

    Full Text Available Reaching decisions in the process of establishment and operationof a regional transport logistics terminal performingintermodal transport and related activities should be based onthe results of preliminary analysis. The selection of the appropriatelocation for the regional transport logistics terminal is ofcrucial importance as it affects directly and/or indirectly the initialfinancial investment, environmental and spatial issues aswell as terminal operating costs and commercial sustainability.In the decision-making process regarding the location ofintermodal terminals or with regard to building of a new regionalintermodal terminal at a specific location a thoroughtransport logistics analysis should be performed. The paperpresents the methodology developed for transport logisticsanalysis of regional intermodal transport logistics terminals,based on the sets of parameters, criteria and indicators whichenable the determination of the overall performance index for aparticular terminal location.

  10. Understanding and quantifying cognitive complexity level in mathematical problem solving items

    Directory of Open Access Journals (Sweden)

    SUSAN E. EMBRETSON

    2008-09-01

    Full Text Available The linear logistic test model (LLTM; Fischer, 1973 has been applied to a wide variety of new tests. When the LLTM application involves item complexity variables that are both theoretically interesting and empirically supported, several advantages can result. These advantages include elaborating construct validity at the item level, defining variables for test design, predicting parameters of new items, item banking by sources of complexity and providing a basis for item design and item generation. However, despite the many advantages of applying LLTM to test items, it has been applied less often to understand the sources of complexity for large-scale operational test items. Instead, previously calibrated item parameters are modeled using regression techniques because raw item response data often cannot be made available. In the current study, both LLTM and regression modeling are applied to mathematical problem solving items from a widely used test. The findings from the two methods are compared and contrasted for their implications for continued development of ability and achievement tests based on mathematical problem solving items.

  11. Continuous Online Item Calibration: Parameter Recovery and Item Utilization.

    Science.gov (United States)

    Ren, Hao; van der Linden, Wim J; Diao, Qi

    2017-06-01

    Parameter recovery and item utilization were investigated for different designs for online test item calibration. The design was adaptive in a double sense: it assumed both adaptive testing of examinees from an operational pool of previously calibrated items and adaptive assignment of field-test items to the examinees. Four criteria of optimality for the assignment of the field-test items were used, each of them based on the information in the posterior distributions of the examinee's ability parameter during adaptive testing as well as the sequentially updated posterior distributions of the field-test item parameters. In addition, different stopping rules based on target values for the posterior standard deviations of the field-test parameters and the size of the calibration sample were used. The impact of each of the criteria and stopping rules on the statistical efficiency of the estimates of the field-test parameters and on the time spent by the items in the calibration procedure was investigated. Recommendations as to the practical use of the designs are given.

  12. Logistics and logistics processes in a tourism destination

    OpenAIRE

    Mrnjavac, Edna; Ivanovic, Sasa

    2007-01-01

    Logistics is a scientific discipline, a business function and an activity that, in recent times, is increasingly being applied to economic and social activities, because it enables the production of a quality product at a moderate cost. With regard to the trend for globally applying the principles of logistics to all spheres of human activities, the phenomenon of tourism presents a special challenge. Moreover, it is becoming evident that a quality tourism product, the design of which is linke...

  13. Development of logistics information systems

    Directory of Open Access Journals (Sweden)

    Milan Ž. Dronjak

    2012-10-01

    Full Text Available An adequate logistics information system provides real time automated data processing, distribution and of information according to Terrain Commander's requirements, which leads to timely fulfillment of logistic demands of units. SAP ERP The SAP ERP application is the integrated (ERP software capable of working with complex organisational structures, personnel, equipment, and finance. It enables planning and combining forces for every type of operations. The system also enables the determination of the readiness status of modelled forces. ISL The Information System for Logistics (ISL is a comprehensive information system of the Ministry of Defence (MoD and the Army of the Czech Republic that covers many areas: acquisition, supply, ammunition and equipment maintenance, logistics, etc. The ISL provides support for military logistics in all important areas of consumer and acquisition logistics, satisfaying all kinds of Defence Forces needs in the country and abroad. LOGFAS The information system LOGFAS comprises Logistics Database (LOGBASE, Movement and Transportation software (M&T, Allied Command Europe Resource Optimisation Software System (ACROSS and Logistic Reporting System (LOGREP. The Logistics Database LOGBASE represents a logistics information source and also a database related to assets, forces, geography, infrastructure, targets, supplies, movements and medical data. The main software tools which rely on the LOGBASE are M&T, ACROSS and LOGREP. GCSS-Army The original impetus to create the SALE came in the mid-90s when the United States Department of Defense (DoD started a logistics modernisation programme. One of tasks was to build The Single Army Logistics Enterprise (SALE for the purpose of covering the whole organisational structure of the DoD. There are three components of the SALE: GCSS-Army, PLM+ and LMP. Each of them uses the commercial Enterprise Resource Planning SAP Software with a Web access. The main component, GCSS

  14. A two-parameter criterion for classifying the explodability of massive stars by the neutrino-driven mechanism

    CERN Document Server

    Ertl, T; Woosley, S E; Sukhbold, T; Ugliano, M

    2015-01-01

    Thus far, judging the fate of a massive star (either a neutron star (NS) or a black hole) solely by its structure prior to core collapse has been ambiguous. Our work and previous attempts find a non-monotonic variation of successful and failed supernovae with zero-age main-sequence mass, for which no single structural parameter can serve as a good predictive measure. However, we identify two parameters computed from the pre-collapse structure of the progenitor, which in combination allow for a clear separation of exploding and non-exploding cases with only few exceptions (~1--2.5%) in our set of 621 investigated stellar models. One parameter is M4, defining the enclosed mass for a dimensionless entropy per nucleon of s = 4, and the other is mu4 = dm/dr|_{s=4}, being the mass-derivative at this location. The two parameters mu4 and M4*mu4 can be directly linked to the mass-infall rate, Mdot, of the collapsing star and the electron-type neutrino luminosity of the accreting proto-NS, L_nue ~ M_ns*Mdot, which play...

  15. The analysis and application of simplified two-parameter moveout equation for C-waves in VTI anisotropy media

    Institute of Scientific and Technical Information of China (English)

    Li Xiao-Ming; Chen Shuang-Quan; Li Xiang-Yang

    2013-01-01

    Several parameters are needed to describe the converted-wave (C-wave) moveout in processing multi-component seismic data, because of asymmetric raypaths and anisotropy. As the number of parameters increases, the converted wave data processing and analysis becomes more complex. This paper develops a new moveout equation with two parameters for C-waves in vertical transverse isotropy (VTI) media. The two parameters are the C-wave stacking velocity (VC2) and the squared velocity ratio (γvti) between the horizontal P-wave velocity and C-wave stacking velocity. The new equation has fewer parameters, but retains the same applicability as previous ones. The applicability of the new equation and the accuracy of the parameter estimation are checked using model and real data. The form of the new equation is the same as that for layered isotropic media. The new equation can simplify the procedure for C-wave processing and parameter estimation in VTI media, and can be applied to real C-wave processing and interpretation. Accurate VC2 andγvti can be deduced from C-wave data alone using the double-scanning method, and the velocity ratio model is suitable for event matching between P-and C-wave data.

  16. 艾森克人格问卷项目质量的项目反应理论分析%AN ITEM ANALYSIS OF EPQ ON THE ITEM RESPONSE THEORY

    Institute of Scientific and Technical Information of China (English)

    杨建原; 何壮; 赵守盈

    2012-01-01

    It is 30 years since Eysenek' s personality (EPQ) theory was first introduced to China, and the latest norm was published in 2000. Exposed too much in the past 10 years, its applicability needs to be tested empirically again with present samples. The aim of this paper is to analyze EPQ' s items' properties under IRT, focusing on the measurement accuracy of the items. The program MULTILOG 7. 03 was employed as the tool for parameter estimation. In the estimating procedure, maximum likelihood estimation and two parameter logistic model were utilized. The parameters of difficulty, discrimination and information curve were analyzed in detail. The results indicated that the data accorded with the basic assumptions in IRT; unidimensionality, monotone increasing and invariance of parameter estimation etc. The difficulty and discrimination of most of the EPQ' s items met the theoretical requirements, which demonstrated the revision of the questionnaire was quite successful; many erroneous judgments, nevertheless, should be aroused if it is applied to make assessments or interventions to the subject due to its limited amount of information obtained from the subject. As an essential complement to CTT to analyze items, IRT will be widely used in psychological and education test studies in the future.%使用MULTILOG 7.03软件的边际极大似然估计法,选取双参数Logistic模型对某大学2011级新生的EPQ测试数据进行分析,针对项目区分度、项目难度、信息量等指标对各项目及各分量表进行深入探讨.结果显示:数据符合项目反应理论的基本假设;多数项目的区分度、难度达到理论要求.但E、P、N三个分测验在划界分数点上得到的信息量有限,难以对被试做出良好的区分;三个分测验各自的总信息量未达到理论要求.

  17. Challenges of Green Logistics in Southeast Europe

    OpenAIRE

    Bojan Beškovnik; Livio Jakomin

    2010-01-01

    This paper describes the trends towards green logistics in global aspect and challenges of adopting green logistics in the region of Southeast Europe. Modern logistics with supply chain management is experiencing a period of important evolution. From reversible logistics, we came to green logistics, which is a wider concept of environmentally friendly thinking. Reverse logistics includes processes of movements and transportation of waste from users to recycling plants; meanwhile, green logist...

  18. Assessing item fit for unidimensional item response theory models using residuals from estimated item response functions.

    Science.gov (United States)

    Haberman, Shelby J; Sinharay, Sandip; Chon, Kyong Hee

    2013-07-01

    Residual analysis (e.g. Hambleton & Swaminathan, Item response theory: principles and applications, Kluwer Academic, Boston, 1985; Hambleton, Swaminathan, & Rogers, Fundamentals of item response theory, Sage, Newbury Park, 1991) is a popular method to assess fit of item response theory (IRT) models. We suggest a form of residual analysis that may be applied to assess item fit for unidimensional IRT models. The residual analysis consists of a comparison of the maximum-likelihood estimate of the item characteristic curve with an alternative ratio estimate of the item characteristic curve. The large sample distribution of the residual is proved to be standardized normal when the IRT model fits the data. We compare the performance of our suggested residual to the standardized residual of Hambleton et al. (Fundamentals of item response theory, Sage, Newbury Park, 1991) in a detailed simulation study. We then calculate our suggested residuals using data from an operational test. The residuals appear to be useful in assessing the item fit for unidimensional IRT models.

  19. Logistics in smallpox: the legacy.

    Science.gov (United States)

    Wickett, John; Carrasco, Peter

    2011-12-30

    Logistics, defined as "the time-related positioning of resources" was critical to the implementation of the smallpox eradication strategy of surveillance and containment. Logistical challenges in the smallpox programme included vaccine delivery, supplies, staffing, vehicle maintenance, and financing. Ensuring mobility was essential as health workers had to travel to outbreaks to contain them. Three examples illustrate a range of logistic challenges which required imagination and innovation. Standard price lists were developed to expedite vehicle maintenance and repair in Bihar, India. Innovative staffing ensured an adequate infrastructure for vehicle maintenance in Bangladesh. The use of disaster relief mechanisms in Somalia provided airlifts, vehicles and funding within 27 days of their initiation. In contrast the Expanded Programme on Immunization (EPI) faces more complex logistical challenges. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Fungible weights in logistic regression.

    Science.gov (United States)

    Jones, Jeff A; Waller, Niels G

    2016-06-01

    In this article we develop methods for assessing parameter sensitivity in logistic regression models. To set the stage for this work, we first review Waller's (2008) equations for computing fungible weights in linear regression. Next, we describe 2 methods for computing fungible weights in logistic regression. To demonstrate the utility of these methods, we compute fungible logistic regression weights using data from the Centers for Disease Control and Prevention's (2010) Youth Risk Behavior Surveillance Survey, and we illustrate how these alternate weights can be used to evaluate parameter sensitivity. To make our work accessible to the research community, we provide R code (R Core Team, 2015) that will generate both kinds of fungible logistic regression weights. (PsycINFO Database Record

  1. Logistics Reduction and Repurposing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) project will enable a mission-independent cradle-to-grave-to-cradle...

  2. NFORMATION TECHNOLOGIES IN INTEGRATED LOGISTICS

    National Research Council Canada - National Science Library

    Karolina S Prokopovic; Tijana B Prokopovic; Miloje A Jelic

    2016-01-01

      The rapid development of the Internet and the use of new possibilities which the digital technologies have brought about, have made significant changes in all the areas of business, including logistics...

  3. Case Study on Logistics Performance

    Directory of Open Access Journals (Sweden)

    Shahryar Sorooshian

    2013-05-01

    Full Text Available The paper presents research carried out at a medium‐size manufacturing organization in east Asia. The study tries to highlight the importance of supply chain management; specifically, our aim for this study is to understand logistics and performance measurement in the logistics and supply chain, and we include a theoretical discussion of online data collected and a case study of the logistic performance of a real organization. The study also examines the performance of the selected company, identifies the problems and provides recommendations for improvements. This study can be a guide for business advisers and those interested in analysing company performance, especially from a logistics viewpoint. We also suggest the methodology of this case study for those who want to have a better understanding of a business environment before starting their own business, or for benchmarking practice during strategic planning.

  4. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    National Research Council Canada - National Science Library

    Ioana Olariu

    2014-01-01

    ... of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle...

  5. Tailored logistics: the next advantage.

    Science.gov (United States)

    Fuller, J B; O'Conor, J; Rawlinson, R

    1993-01-01

    How many top executives have ever visited with managers who move materials from the factory to the store? How many still reduce the costs of logistics to the rent of warehouses and the fees charged by common carriers? To judge by hours of senior management attention, logistics problems do not rank high. But logistics have the potential to become the next governing element of strategy. Whether they know it or not, senior managers of every retail store and diversified manufacturing company compete in logistically distinct businesses. Customer needs vary, and companies can tailor their logistics systems to serve their customers better and more profitably. Companies do not create value for customers and sustainable advantage for themselves merely by offering varieties of goods. Rather, they offer goods in distinct ways. A particular can of Coca-Cola, for example, might be a can of Coca-Cola going to a vending machine, or a can of Coca-Cola that comes with billing services. There is a fortune buried in this distinction. The goal of logistics strategy is building distinct approaches to distinct groups of customers. The first step is organizing a cross-functional team to proceed through the following steps: segmenting customers according to purchase criteria, establishing different standards of service for different customer segments, tailoring logistics pipelines to support each segment, and creating economics of scale to determine which assets can be shared among various pipelines. The goal of establishing logistically distinct businesses is familiar: improved knowledge of customers and improved means of satisfying them.

  6. INFORMATION SECURITY IN LOGISTICS COOPERATION

    Directory of Open Access Journals (Sweden)

    Tomasz Małkus

    2015-03-01

    Full Text Available Cooperation of suppliers of raw materials, semi-finished products, finished products, wholesalers, retailers in the form of the supply chain, as well as outsourcing of specialized logistics service require ensuring adequate support of information. It concerns the use of appropriate computer tools. The security of information in such conditions of collaboration becomes the important problem for parties of contract. The objective of the paper is to characterize main issues relating to security of information in logistics cooperation.

  7. Logistics sprawl in Los Angeles

    OpenAIRE

    DABLANC, Laetitia

    2013-01-01

    'Logistics sprawl' is the spatial deconcentration of logistics facilities and distribution centers in metropolitan areas. It has been a dominant spatial pattern for the last decades in metropolitan areas of developed countries. Starting in the 1980s, the U.S. and many other parts of the world entered a 'new distribution economy' (Hesse and Rodrigue, 2004), an economy largely dependent upon efficient and increasingly globalized networks of goods distribution and just-in-time operations. This h...

  8. Information Logistics Research report 2

    OpenAIRE

    Willems, A; Hajdasinski, A.K.; Willems, J

    2009-01-01

    The goal of this research report is to further explore the concept of Information Logistics (IL), which refers to the usage and dispatch of information and methods of logistics able to support those processes. This report is based upon 6 questions that examine IL in organizations, healthcare organizations in particular. These questions are related to information handling within organizations, the required structure, information maturity levels, quality issues and context aware situations that...

  9. Quality evaluation in logistic services

    OpenAIRE

    Franceschini, Fiorenzo; Rafele, Carlo

    2000-01-01

    The paper highlights some problems relevant to the quality measurements in logistic services. "Traditional" logistic indicators are compared with the service dimensions defined in the Parasuraman-Zeithaml-Berry model. Furthermore, the problem of service indicators aging is analyzed and discussed. In order to enhance readers' ability to contribute to the development in the field, the authors pose open-ended questions in the article

  10. Desenvolvimento de uma escala para medir o potencial empreendedor utilizando a Teoria da Resposta ao Item (TRI Development of a scale to measure the entrepreneurial potential using the Item Response Theory (IRT

    Directory of Open Access Journals (Sweden)

    Luciano Ricardo Rath Alves

    2011-01-01

    referenced in theories of entrepreneur's personality. The samples include 664 undergraduate and graduate students of Brazilian universitie, and 100 entrepreneurs of the state of Alagoas. A two- parameter logistic IRT model was used. The parameter estimates were obtained from a sample of 764 people who responded to an instrument containing 103 items. The information and the standard error curves and the qualitative interpretation of the scale levels allowed us to determine the most appropriate range for the instrument use. The results showed that the scale is most adequate to evaluate individuals with low to moderately high entrepreneurial potential. Therefore, it is suggested that new items are incorporated into the instrument to measure and interpret even higher levels. The Item Response Theory allows the calibration of new items to measure entrepreneurs with high entrepreneurial potential using previously obtained data.

  11. NASA Space Rocket Logistics Challenges

    Science.gov (United States)

    Neeley, James R.; Jones, James V.; Watson, Michael D.; Bramon, Christopher J.; Inman, Sharon K.; Tuttle, Loraine

    2014-01-01

    The Space Launch System (SLS) is the new NASA heavy lift launch vehicle and is scheduled for its first mission in 2017. The goal of the first mission, which will be uncrewed, is to demonstrate the integrated system performance of the SLS rocket and spacecraft before a crewed flight in 2021. SLS has many of the same logistics challenges as any other large scale program. Common logistics concerns for SLS include integration of discreet programs geographically separated, multiple prime contractors with distinct and different goals, schedule pressures and funding constraints. However, SLS also faces unique challenges. The new program is a confluence of new hardware and heritage, with heritage hardware constituting seventy-five percent of the program. This unique approach to design makes logistics concerns such as commonality especially problematic. Additionally, a very low manifest rate of one flight every four years makes logistics comparatively expensive. That, along with the SLS architecture being developed using a block upgrade evolutionary approach, exacerbates long-range planning for supportability considerations. These common and unique logistics challenges must be clearly identified and tackled to allow SLS to have a successful program. This paper will address the common and unique challenges facing the SLS programs, along with the analysis and decisions the NASA Logistics engineers are making to mitigate the threats posed by each.

  12. Faculty development on item writing substantially improves item quality.

    Science.gov (United States)

    Naeem, Naghma; van der Vleuten, Cees; Alfaris, Eiad Abdelmohsen

    2012-08-01

    The quality of items written for in-house examinations in medical schools remains a cause of concern. Several faculty development programs are aimed at improving faculty's item writing skills. The purpose of this study was to evaluate the effectiveness of a faculty development program in item development. An objective method was developed and used to assess improvement in faculty's competence to develop high quality test items. This was a quasi experimental study with a pretest-midtest-posttest design. A convenience sample of 51 faculty members participated. Structured checklists were used to assess the quality of test items at each phase of the study. Group scores were analyzed using repeated measures analysis of variance. The results showed a significant increase in participants' mean scores on Multiple Choice Questions, Short Answer Questions and Objective Structured Clinical Examination checklists from pretest to posttest (p development are generally lacking in quality. It also provides evidence of the value of faculty development in improving the quality of items generated by faculty.

  13. E-logistics and M-logistics in information economy

    Directory of Open Access Journals (Sweden)

    Volodymyr I. Skitsko

    2016-03-01

    Full Text Available Background: The purpose of this article is to study the concepts of electronic and mobile logistics as components of the information economy within which the effective management of relevant information flows can be performed today. Materials: The article is based on the available recent scientific-theoretical and professional practical research and publications. Introduction to these studies and publications allowed to conclude the diversity, importance and relevance of the proposed in this work problem and the existence of the understudied aspects. Results: This article proposes author definition of m-logistics as part of an information logistics, describes the aspects of its functioning and demonstrates its place in information economy. Conclusion: This work may be a starting point for further research in the field of e-logistics and m-logistics. For example, there is a need for the development and introduction of modern economic and mathematical methods and models by which the effective information management in modern business environment can be performed.

  14. The Hamilton depression scale. Evaluation of objectivity using logistic models.

    Science.gov (United States)

    Bech, P; Allerup, P; Gram, L F; Reisby, N; Rosenberg, R; Jacobsen, O; Nagy, A

    1981-03-01

    The consistency of the Hamilton Depression Scale (HDS) as a measure of the severity of depressive states has been examined when the scale was used weekly during a trial when imipramine. By use of logistic models (Rasch) the consistency of the HDS has been considered across patient-variables as age, sex, plasma levels of imipramine, and diagnosis. The results showed that the original 17-item HDS was without adequate consistency, i.e. the total score of the sample of items was no one-dimensional measure of depressive states. However, a melancholia subscale of the HDS contained items the total of which can be used to compare patients quantitatively, although in some part of the analysis one of these items showed ceiling effect. It was concluded that the melancholia subscale (containing the items depressed mood, guilt, work and interests, retardation, psychic anxiety, and general somatic symptoms) can form the basis for further improvements in the field of quantitative rating scales for depressive states.

  15. Application of Two-Parameter Extrapolation for Solution of Boundary-Value Problem on Semi-Axis

    CERN Document Server

    Zhidkov, E P

    2000-01-01

    A method for refining approximate eigenvalues and eigenfunctions for a boundary-value problem on a half-axis is suggested. To solve the problem numerically, one has to solve a problem on a finite segment [0,R] instead of the original problem on the interval [0,\\infty). This replacement leads to eigenvalues' and eigenfunctions' errors. To choose R beforehand for obtaining their required accuracy is often impossible. Thus, one has to resolve the problem on [0,R] with larger R. If there are two eigenvalues or two eigenfunctions that correspond to different segments, the suggested method allows one to improve the accuracy of the eigenvalue and the eigenfunction for the original problem by means of extrapolation along the segment. This approach is similar to Richardson's method. Moreover, a two-parameter extrapolation is described. It is combination of the extrapolation along the segment and Richardson's extrapolation along a discretization step.

  16. Counting Frequencies from Zotero Items

    Directory of Open Access Journals (Sweden)

    Spencer Roberts

    2013-04-01

    Full Text Available In Counting Frequencies you learned how to count the frequency of specific words in a list using python. In this lesson, we will expand on that topic by showing you how to get information from Zotero HTML items, save the content from those items, and count the frequencies of words. It may be beneficial to look over the previous lesson before we begin.

  17. Detecting Differential Item Functioning in the Japanese Version of the Multiple Affect Adjective Check List--Revised

    Science.gov (United States)

    Yasuda, Tomoyuki; Lei, Pui-Wa; Suen, Hoi K.

    2007-01-01

    This study examines the differential item functioning (DIF) of the English version and the Japanese-translated version of the Multiple Affect Adjective Check List--Revised (MAACL-R) using the logistic regression (LR) procedure. The results of the LR are supplemented by multiple group confirmatory factor analysis (MGCFA). A total of five items are…

  18. Logistics Management: New trends in the Reverse Logistics

    Science.gov (United States)

    Antonyová, A.; Antony, P.; Soewito, B.

    2016-04-01

    Present level and quality of the environment are directly dependent on our access to natural resources, as well as their sustainability. In particular production activities and phenomena associated with it have a direct impact on the future of our planet. Recycling process, which in large enterprises often becomes an important and integral part of the production program, is usually in small and medium-sized enterprises problematic. We can specify a few factors, which have direct impact on the development and successful application of the effective reverse logistics system. Find the ways to economically acceptable model of reverse logistics, focusing on converting waste materials for renewable energy, is the task in progress.

  19. Multilevel Modeling of Item Position Effects

    Science.gov (United States)

    Albano, Anthony D.

    2013-01-01

    In many testing programs it is assumed that the context or position in which an item is administered does not have a differential effect on examinee responses to the item. Violations of this assumption may bias item response theory estimates of item and person parameters. This study examines the potentially biasing effects of item position. A…

  20. Defense Logistics: DOD Has Taken Actions to Improve Some Segments of the Materiel Distribution System

    Science.gov (United States)

    2012-08-03

    shipment delivery time data by reviewing related data documentation, analyzing the methodology used to determine DSO improvements, and interviewing... delivery time , also known as logistics response time, measures the time from submission of a requisition for an item to the delivery of the item to a retail...shipment delivery - time improvements within the U.S. Central Command, the U.S. European Command, and the U.S. Pacific Command areas of responsibility

  1. Cold Regions Logistic Supportability Testing of Electronic, Avionic and Communications Equipment.

    Science.gov (United States)

    2014-09-26

    A18 887 COLD REGIONS LOGISTIC SUPPORTABILITY TESTING OF / AS ELECTRONIC AVIONIC AMD CO..IUI ANY T EST AND EVALUATION COMAND ABERDEEN PROVING GROUND...optimum durability and service life of materiel. (b) To eliminate field maintenance problems encountered in earlier design items. (c) For ease of...heat sensitive). 5.2.2 Analysis. Assess the impact of each supply support anomaly un- covered in relation to the test item. Include comments as to the

  2. SELECTED PROBLEMS OF REVERSE LOGISTICS IN POLAND

    OpenAIRE

    Agata Mesjasz-Lech

    2009-01-01

    This paper presents the essence of reverse logistics and directions of physical and information flows between logistic network partners. It also analyses effects of implementation of the principles of reverse logistics in Poland in the years 2004-2007

  3. Social logistics –paths of development

    OpenAIRE

    Kolodziejczyk, P; J. Szoltysek

    2011-01-01

    The paper aims to introduce discussion about a new domain of practical application of logistics the social logistics, which is the third part (after militaristic and commercial) needed for a full view of the contemporary logistics application possibilities.

  4. Logistics potentials in business competitive advantage creation

    OpenAIRE

    Rafał Matwiejczuk

    2013-01-01

    Background: Companies constantly search for ways to achieve and sustain long-term competitive advantage. Among the factors influencing the competitive advantage creation there are so called logistics potentials, which constitute a component part of a business strategic potentials. Logistics resources, logistics capabilities and logistics competences are the main components of the logistics potentials structure and hierarchy. Methods: In order to recognize the logistics potentials which de...

  5. Technology in health care logistics

    DEFF Research Database (Denmark)

    Jørgensen, Pelle; Wallin, Michael

    In most of the developed countries hospitals are facing a major challenge – they have to provide more health care using the same resources. Due to the demographic trend and the increasing share of the population being in a more health-demanding age, the hospitals will have to deal with more...... presents an analytical model that can analyse the logistical system using a holistic approach, and explore the possibility of using technology to improve the current system. A logistical system is one of the different flows happening at a hospital. Included in the analytical model is a performance...... assessment tool, which has been designed to assess the performance of the logistical system, thereby pinpointing where the system is performing poorly. Additionally the model and tool makes it possible to evaluate various technologies that can be used to improve and optimise the existing system...

  6. Green Logistics: the Carbon Agenda

    Directory of Open Access Journals (Sweden)

    2010-09-01

    Full Text Available Over the next few decades European companies will come under intense pressure to cut their greenhouse gas (GHG emissions in an effort to achieve very ambitious carbon reduction targets at national, EU and global levels by 2050. This paper presents a framework for the decarbonisation of their logistical activities based on five key freight transport parameters: freight transport intensity, modal split, vehicle utilization, energy efficiency and the carbon intensity of the energy used in logistics. It examines the potential to cut GHG emissions by altering each of these parameters. Consideration is also given to the decarbonisation of warehousing operations. It is concluded that many of the GHG-reduction measures will also yield financial benefit. The decarbonisation of other sectors of the economy may, however, generate greater demand for logistics services.

  7. A Solution to Separation and Multicollinearity in Multiple Logistic Regression.

    Science.gov (United States)

    Shen, Jianzhao; Gao, Sujuan

    2008-10-01

    In dementia screening tests, item selection for shortening an existing screening test can be achieved using multiple logistic regression. However, maximum likelihood estimates for such logistic regression models often experience serious bias or even non-existence because of separation and multicollinearity problems resulting from a large number of highly correlated items. Firth (1993, Biometrika, 80(1), 27-38) proposed a penalized likelihood estimator for generalized linear models and it was shown to reduce bias and the non-existence problems. The ridge regression has been used in logistic regression to stabilize the estimates in cases of multicollinearity. However, neither solves the problems for each other. In this paper, we propose a double penalized maximum likelihood estimator combining Firth's penalized likelihood equation with a ridge parameter. We present a simulation study evaluating the empirical performance of the double penalized likelihood estimator in small to moderate sample sizes. We demonstrate the proposed approach using a current screening data from a community-based dementia study.

  8. Empirical Study of E-logistics System Based on Tibet Logistics Industry

    OpenAIRE

    Liu, Yu

    2013-01-01

    With the rapid growth of E-logistics in the global logistics industry, it is important to get insight into E-logistics system in Chinese logistics industry. Regarding the current situation of E-logistics of Chinese logistics industry, there are still many problems to be concerned and resolved. This paper will review the concepts and theoretical background of E-logistics System from previous researches. After acknowledging the essential issues on E-logistics System, a research model is designe...

  9. Empirical Study of E-logistics System Based on Tibet Logistics Industry

    OpenAIRE

    Liu, Yu

    2013-01-01

    With the rapid growth of E-logistics in the global logistics industry, it is important to get insight into E-logistics system in Chinese logistics industry. Regarding the current situation of E-logistics of Chinese logistics industry, there are still many problems to be concerned and resolved. This paper will review the concepts and theoretical background of E-logistics System from previous researches. After acknowledging the essential issues on E-logistics System, a research model is designe...

  10. Logistics background study: underground mining

    Energy Technology Data Exchange (ETDEWEB)

    Hanslovan, J. J.; Visovsky, R. G.

    1982-02-01

    Logistical functions that are normally associated with US underground coal mining are investigated and analyzed. These functions imply all activities and services that support the producing sections of the mine. The report provides a better understanding of how these functions impact coal production in terms of time, cost, and safety. Major underground logistics activities are analyzed and include: transportation and personnel, supplies and equipment; transportation of coal and rock; electrical distribution and communications systems; water handling; hydraulics; and ventilation systems. Recommended areas for future research are identified and prioritized.

  11. 不同认知成分在图形推理测验项目难度预测中的作用%The Role of Different Cognitive Components in the Prediction of the Figural Reasoning Test's Item Difficulty

    Institute of Scientific and Technical Information of China (English)

    李中权; 王力; 张厚粲; 周仁来

    2011-01-01

    Figural reasoning tests (as represented by Raven's tests) are widely applied as effective measures of fluid intelligence in recruitment and personnel selection. However, several studies have revealed that those tests are not appropriate anymore due to high item exposure rates. Computerized automatic item generation (AIG) has gradually been recognized as a promising technique in handling item exposure. Understanding sources of item variation constitutes the initial stage of Computerized AIG, that is, searching for the underlying processing components and the stimuli that significantly influence those components. Some studies have explored sources of item variation, but so far there are no consistent results. This study investigated the relation between item difficulties and stimuli factors (e.g., familiarity of figures, abstraction of attributes, perceptual organization, and memory load) and determines the relative importance of those factors in predicting item difficulities.Eight sets of figural reasoning tests (each set containing 14 items imitating items from Raven's Advanced Progressive Matrics, APM) were constructed manipulating the familiarity of figures, the degree of abstraction of attributes, the perceptual organization as well as the types and number of rules. Using anchor-test design, these tests were administrated via the internet to 6323 participants with 10 items drawing from APAM as anchor items; thus, each participant completed 14 items from either one set and 10 anchor items within half an hour. In order to prevent participants from using response elimination strategy, we presented one item stem first, then alternatives in turn, and asked participants to determine which alternative was the best.DIMTEST analyses were conducted on the participants' responses on each of eight tests. Results showed that items measure a single dimension on each test. Likelihood ratio test indicated that the data fit two-parameter logistic model (2PL) best. Items were

  12. Item response theory analysis to evaluate reliability and minimal clinically important change of the Roland-Morris Disability Questionnaire in patients with severe disability due to back pain from vertebral compression fractures.

    Science.gov (United States)

    Lee, Minji K; Yost, Kathleen J; McDonald, Jennifer S; Dougherty, Ryne W; Vine, Roanna L; Kallmes, David F

    2017-06-01

    The majority of validation done on the Roland-Morris Disability Questionnaire (RMDQ) has been in patients with mild or moderate disability. There is paucity of research focusing on the psychometric quality of the RMDQ in patients with severe disability. To evaluate the psychometric quality of the RMDQ in patients with severe disability. Observational clinical study. The sample consisted of 214 patients with painful vertebral compression fractures who underwent vertebroplasty or kyphoplasty. The 23-item version of the RMDQ was completed at two time points: baseline and 30-day postintervention follow-up. With the two-parameter logistic unidimensional item response theory (IRT) analyses, we derived the range of scores that produced reliable measurement and investigated the minimal clinically important difference (MCID). Scores for 214 (100%) patients at baseline and 108 (50%) patients at follow-up did not meet the reliability criterion of 0.90 or higher, with the majority of patients having disability due to back pain that was too severe to be reliably measured by the RMDQ. Depending on methodology, MCID estimates ranged from 2 to 8 points and the proportion of patients classified as having experienced meaningful improvement ranged from 26% to 68%. A greater change in score was needed at the extreme ends of the score scale to be classified as having achieved MCID using IRT methods. Replacing items measuring moderate disability with items measuring severe disability could yield a version of the RMDQ that better targets patients with severe disability due to back pain. Improved precision in measuring disability would be valuable to clinicians who treat patients with greater functional impairments. Caution is needed when choosing criteria for interpreting meaningful change using the RMDQ. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Evaluating construct validity of the second version of the Copenhagen Psychosocial Questionnaire through analysis of differential item functioning and differential item effect

    DEFF Research Database (Denmark)

    Bjorner, Jakob Bue; Pejtersen, Jan Hyld

    2010-01-01

    AIMS: To evaluate the construct validity of the Copenhagen Psychosocial Questionnaire II (COPSOQ II) by means of tests for differential item functioning (DIF) and differential item effect (DIE). METHODS: We used a Danish general population postal survey (n = 4,732 with 3,517 wage earners) with a ...... shortform measures and to improve the conceptual framework, items and scales of the COPSOQ II. CONCLUSIONS: We conclude that tests of DIF and DIE are useful for evaluating construct validity.......) with a one-year register based follow up for long-term sickness absence. DIF was evaluated against age, gender, education, social class, public/private sector employment, and job type using ordinal logistic regression. DIE was evaluated against job satisfaction and self-rated health (using ordinal logistic...

  14. "Logistic analysis of algae cultivation"

    NARCIS (Netherlands)

    Slegers, P.M.; Leduc, S.; Wijffels, R.H.; Straten, van G.; Boxtel, van A.J.B.

    2015-01-01

    Energy requirements for resource transport of algae cultivation are unknown. This work describes the quantitative analysis of energy requirements for water and CO2 transport. Algae cultivation models were combined with the quantitative logistic decision model ‘BeWhere’ for the regions Benelux

  15. Quantitative Models for Reverse Logistics

    NARCIS (Netherlands)

    M. Fleischmann (Moritz)

    2000-01-01

    textabstractEconomic, marketing, and legislative considerations are increasingly leading companies to take back and recover their products after use. From a logistics perspective, these initiatives give rise to new goods flows from the user back to the producer. The management of these goods flows o

  16. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-01-01

    Full Text Available As the power of consumers is growing, the product return for customer service and customer retention has become a common practice in the competitive market, which propels the recent practice of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle. Reverse logistics is the flow and management of products, packaging, components and information from the point of consumption to the point of origin. It is a collection of practices similar to those of supply chain management, but in the opposite direction, from downstream to upstream. It involves activities such as reuse, repair, remanufacture, refurbish, reclaim and recycle. For the conventional forward logistics systems, the flow starts upstream as raw materials, later as manufactured parts and components to be assembled and continues downstream to reach customers as final products to be disposed once they reach their economic or useful lives. In reverse logistics, the disposed products are pushed upstream to be repaired, remanufactured, refurbished, and disassembled into components to be reused or as raw material to be recycled for later use.

  17. Decision Support Systems in Logistics

    Science.gov (United States)

    Encheva, Sylvia; Kondratenko, Yuriy; Solesvik, Maryna Z.; Tumin, Sharil

    2008-11-01

    Experience shows that intuitive judgment and decision making is not allwas of sufficient quality and is getting worse in the presence of increasing complexity. One of the solutions to such problems is to use decision support systems. This paper focuses on assessment criteria of delivery quality in the transport logistics.

  18. Logistics support of space facilities

    Science.gov (United States)

    Lewis, William C.

    1988-01-01

    The logistic support of space facilities is described, with special attention given to the problem of sizing the inventory of ready spares kept at the space facility. Where possible, data from the Space Shuttle Orbiter is extrapolated to provide numerical estimates for space facilities. Attention is also given to repair effort estimation and long duration missions.

  19. A Framework for Reverse Logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2003-01-01

    textabstractReverse Logistics has been stretching out worldwide, involving all the layers of supply chains in various industry sectors. While some actors in the chain have been forced to take products back, others have pro-actively done so, attracted by the value in used products One way or the othe

  20. Woody biomass logistics [Chapter 14

    Science.gov (United States)

    Robert Keefe; Nathaniel Anderson; John Hogland; Ken Muhlenfeld

    2014-01-01

    The economics of using woody biomass as a fuel or feedstock for bioenergy applications is often driven by logistical considerations. Depending on the source of the woody biomass, the acquisition cost of the material is often quite low, sometimes near zero. However, the cost of harvesting, collection, processing, storage, and transportation from the harvest site to end...

  1. Logistics Dynamics and Demographic Change

    NARCIS (Netherlands)

    Klumpp, Matthias; Abidi, Hella; Bioly, Sascha; Buchkremer, Rüdiger; Sandhaus, Gregor; Freitag, Michael; Kotzab, Herbert; Pannek, Jürgen

    2016-01-01

    Change and dynamics in logistics are interestingly driven at the same time by external as well as internal forces. This contribution outlines a big data literature review methodology to overview recognizable external changes and analyzes the interaction of one major trend—demographic change—further

  2. Quantitative Models for Reverse Logistics

    NARCIS (Netherlands)

    M. Fleischmann (Moritz)

    2000-01-01

    markdownabstractEconomic, marketing, and legislative considerations are increasingly leading companies to take back and recover their products after use. From a logistics perspective, these initiatives give rise to new goods flows from the user back to the producer. The management of these goods

  3. Practical methods for dealing with 'not applicable' item responses in the AMC Linear Disability Score project

    Directory of Open Access Journals (Sweden)

    Zwinderman Aeilko H

    2004-06-01

    Full Text Available Abstract Background Whenever questionnaires are used to collect data on constructs, such as functional status or health related quality of life, it is unlikely that all respondents will respond to all items. This paper examines ways of dealing with responses in a 'not applicable' category to items included in the AMC Linear Disability Score (ALDS project item bank. Methods The data examined in this paper come from the responses of 392 respondents to 32 items and form part of the calibration sample for the ALDS item bank. The data are analysed using the one-parameter logistic item response theory model. The four practical strategies for dealing with this type of response are: cold deck imputation; hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. Results The item and respondent population parameter estimates were very similar for the strategies involving hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. The estimates obtained using the cold deck imputation method were substantially different. Conclusions The cold deck imputation method was not considered suitable for use in the ALDS item bank. The other three methods described can be usefully implemented in the ALDS item bank, depending on the purpose of the data analysis to be carried out. These three methods may be useful for other data sets examining similar constructs, when item response theory based methods are used.

  4. Practical methods for dealing with 'not applicable' item responses in the AMC Linear Disability Score project

    Science.gov (United States)

    Holman, Rebecca; Glas, Cees AW; Lindeboom, Robert; Zwinderman, Aeilko H; de Haan, Rob J

    2004-01-01

    Background Whenever questionnaires are used to collect data on constructs, such as functional status or health related quality of life, it is unlikely that all respondents will respond to all items. This paper examines ways of dealing with responses in a 'not applicable' category to items included in the AMC Linear Disability Score (ALDS) project item bank. Methods The data examined in this paper come from the responses of 392 respondents to 32 items and form part of the calibration sample for the ALDS item bank. The data are analysed using the one-parameter logistic item response theory model. The four practical strategies for dealing with this type of response are: cold deck imputation; hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. Results The item and respondent population parameter estimates were very similar for the strategies involving hot deck imputation; treating the missing responses as if these items had never been offered to those individual patients; and using a model which takes account of the 'tendency to respond to items'. The estimates obtained using the cold deck imputation method were substantially different. Conclusions The cold deck imputation method was not considered suitable for use in the ALDS item bank. The other three methods described can be usefully implemented in the ALDS item bank, depending on the purpose of the data analysis to be carried out. These three methods may be useful for other data sets examining similar constructs, when item response theory based methods are used. PMID:15200681

  5. T-stress estimation by the two-parameter approach for a specimen with a V-shaped notch

    Science.gov (United States)

    Bouledroua, O.; Elazzizi, A.; Hadj Meliani, M.; Pluvinage, G.; Matvienko, Y. G.

    2017-05-01

    In the present research, T-stress solutions are provided for a V-shaped notch in the case of surface defects in a pressurised pipeline. The V-shaped notch is analyzed with the use of the finite element method by the Castem2000 commercial software to determine the stress distribution ahead of the notch tip. The notch aspect ratio is varied. In contrast to a crack, it is found that the T-stress is not constant and depends on the distance from the notch tip. To estimate the T-stress in the case of a notch, a novel method is developed, inspired by the volumetric method approach proposed by Pluvinage. The method is based on averaging the T-stress over the effective distance ahead of the notch tip. The effective distance is determined by the point with the minimum stress gradient in the fracture process zone. This approach is successfully used to quantify the constraints of the notch-tip fields for various geometries and loading conditions. Moreover, the proposed T-stress estimation creates a basis for analyzing the crack path under mixed-mode loading from the viewpoint of the two-parameter fracture mechanics.

  6. Defense Logistics: Actions Needed to Improve the Availability of Critical Items during Current and Future Operations

    Science.gov (United States)

    2005-04-01

    and aluminium oxide. The tile is backed by multiple layers of polyethylene fiber. 2 Additional attachments include throat and groin protectors...20548 To order by Phone: Voice: (202) 512-6000 TDD: (202) 512-2537 Fax: (202) 512- 6061 Contact: Web site: www.gao.gov/fraudnet/fraudnet.htm E

  7. Personnel, The Class 0 Supply Item: A Logistics Management Approach to Supplying Combatant Commanders with Warfighters

    Science.gov (United States)

    2012-03-01

    book “The Goal: A Process of Ongoing Improvement”, Eliyahu Goldratt proposed his Theory of Constraints and a method of evaluating processes to...improve their throughput ( Goldratt , 2004). Goldratt argues that before you can improve a process, you have to be able to measure the process, and before...Undersecretary of Defense. 106 Goldratt , E. M. (2004). The Goal: A Process of Ongoing Improvement. North River Press. Hammer, M., & Champy, J. (1993

  8. Australian Item Bank Program: Social Science Item Bank.

    Science.gov (United States)

    Australian Council for Educational Research, Hawthorn.

    After vigorous review, editing, and trial testing, this item bank was compiled to help secondary school teachers construct objective tests in the social sciences. Anthropology, economics, ethnic and cultural studies, geography, history, legal studies, politics, and sociology are among the topics represented. The bank consists of multiple choice…

  9. Research of Logistics Cost Based on Saving Algorithm: A Case of A Certain Logistics Company’s Logistics Cost

    OpenAIRE

    Nie Jing; Zeng Wei Yuan; Jing Hong Lei

    2016-01-01

    In recent years, logistics companies of different sizes has been considerably developed all over the country, with the intensified competitions. To stand out in the competitive market, a logistics company must improve its logistics situation, focus on the function of distribution center, reduce logistics costs for enhancing the impact of supply chain, and rapidly response to customer needs. Thus, how to better design or optimize the existing distribution route for reducing logistics costs bec...

  10. E-logistics and M-logistics in information economy

    OpenAIRE

    Volodymyr I. Skitsko

    2016-01-01

    Background: The purpose of this article is to study the concepts of electronic and mobile logistics as components of the information economy within which the effective management of relevant information flows can be performed today. Materials: The article is based on the available recent scientific-theoretical and professional practical research and publications. Introduction to these studies and publications allowed to conclude the diversity, importance and relevance of the proposed in ...

  11. Logistics Transformation through Sense-and-Respond Logistics Network

    OpenAIRE

    2005-01-01

    Proceedings Paper (for Acquisition Research Program) Commercial and military logistics continue to evolve from amassing supplies, through supply chain management, to (more recently) sense-and-respond networks. The realization that ''demand-pull'' is inherently more efficient than a ''supply-push'' strategy propels the migration from supply chains to demand networks. Major commercial enterprises in the United States and abroad have already transformed their supply chains to include Sense-...

  12. LOGISTICS MANAGEMENT IN THE CONTEMPORARY ECONOMY

    OpenAIRE

    Ion SARBU

    2014-01-01

    The evolution of logistics management as a system in the recent decades can be characterized by the influence of the globalization processes and the economic integration in the European Union. Systemic logistic approach ensured revolutionizing the optimization of the logistics chain. Logistics management must be given to permanent forms of the new legal and organizational structure appropriate to the contemporary economy.

  13. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Grabara, Janusz K.; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  14. Key Trends Shaping the Global Logistics Environment

    DEFF Research Database (Denmark)

    Handfield, Robert; Straube, Frank; Pfohl, Hans-Christian

    A summary from the full study “Trends and Strategies in Logistics and Supply Chain Management. Embracing Global Logistics Complexity to Drive Market Advantage” (2013).......A summary from the full study “Trends and Strategies in Logistics and Supply Chain Management. Embracing Global Logistics Complexity to Drive Market Advantage” (2013)....

  15. Aqua Logistics Opens Office in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Aqua Logistics forays into the region with its subsidiary Aqua Logistics China Ltd. Aqua Logistics Ltd.,India-based full scope multi-national service provider,opened its subsidiary-Aqua Logistics China Ltd.(ALCL) in Beijing on October 23.

  16. INTEGRATING THE LOGISTIC FUNCTION WITHIN ENTERPRISE’S FUNCTIONS

    Directory of Open Access Journals (Sweden)

    Cosmina Remeş

    2013-12-01

    Full Text Available Amplification and diversification of conditions in which an enterprise activates, is reflected in all the activities carried out within such. Coordination of the complex activities taking place within an enterprise requires a good management of information flows, as well as of physical flows. This situation calls for a better organization of activities within the enterprise. Taking into account that a flow implies movement of items in time and space, an issue of the utmost importance is to follow-up their trajectory within the enterprise. By grouping logistic activities within the same function, optimal management of the relationships within the enterprise, as well as interactions between such, is facilitated. Within current competitive context, characterized by a variety of customized offers, reduction of products life span, increasing requirements of the consumers who become ever more demanding, logistics occupies a key position within the continuous quest for the highest quality.

  17. Health care logistics: who has the ball during disaster?

    Science.gov (United States)

    Vanvactor, Jerry D

    2011-05-10

    In contemporary organizations, a wide gamut of options is available for sustaining and supporting health care operations. When disaster strikes, despite having tenable plans for routine replenishment and operations, many organizations find themselves ill-prepared, ill-equipped, and without effective mechanisms in place to sustain operations during the immediate aftermath of a crisis. Health care operations can be abruptly halted due to the non-availability of supply. The purpose of this work is to add to a necessary, growing body of works related specifically to health care logistics preparedness and disaster mitigation. Logistics management is a specialized genre of expertise within the health care industry and is largely contributive to the success or failure of health care organizations. Logistics management requires extensive collaboration among multiple stakeholders-internal and external to an organization. Effective processes and procedures can be largely contributive to the success or failure of organizational operations. This article contributes to the closure of an obvious gap in professional and academic literature related to disaster health care logistics management and provides timely insight into a potential problem for leaders industry-wide. One critical aspect of disaster planning is regard for competent logistics management and the effective provision of necessary items when they are needed most. In many communities, there seems to be little evidence available regarding health care logistics involvement in disaster planning; at times, evidence of planning efforts perceptibly end at intra-organizational doors within facilities. Strategic planners are being continually reminded that health care organizations serve a principal role in emergency preparedness planning and must be prepared to fulfill the associated possibilities without notification. The concern is that not enough attention is being paid to repeated lessons being observed in disasters and

  18. Health care logistics: who has the ball during disaster?

    Directory of Open Access Journals (Sweden)

    Jerry D. VanVactor

    2011-05-01

    Full Text Available In contemporary organizations, a wide gamut of options is available for sustaining and supporting health care operations. When disaster strikes, despite having tenable plans for routine replenishment and operations, many organizations find themselves ill-prepared, ill-equipped, and without effective mechanisms in place to sustain operations during the immediate aftermath of a crisis. Health care operations can be abruptly halted due to the non-availability of supply.The purpose of this work is to add to a necessary, growing body of works related specifically to health care logistics preparedness and disaster mitigation. Logistics management is a specialized genre of expertise within the health care industry and is largely contributive to the success or failure of health care organizations. Logistics management requires extensive collaboration among multiple stakeholders—internal and external to an organization. Effective processes and procedures can be largely contributive to the success or failure of organizational operations. This article contributes to the closure of an obvious gap in professional and academic literature related to disaster health care logistics management and provides timely insight into a potential problem for leaders industry-wide.One critical aspect of disaster planning is regard for competent logistics management and the effective provision of necessary items when they are needed most. In many communities, there seems to be little evidence available regarding health care logistics involvement in disaster planning; at times, evidence of planning efforts perceptibly end at intra-organizational doors within facilities. Strategic planners are being continually reminded that health care organizations serve a principal role in emergency preparedness planning and must be prepared to fulfill the associated possibilities without notification. The concern is that not enough attention is being paid to repeated lessons being

  19. Matrix logistics indicators assessment of distributed transport hub

    Directory of Open Access Journals (Sweden)

    Igor Arefyev

    2014-06-01

    Full Text Available Background: The paper is devoted to the distributed transport hub substantiation and assessment. The paper  was an example of the technique and form an array of logistical factors as variables that determine this condition. Experience in organizing multimodal transport showed that the "bottleneck" of transport logistics are items of cargo handling ports, terminals, freight stations and warehouses. At the core of the solution of these problems is the problem of estimating the variables determine the Multi-purpose Hubs. The aim is to develop a method of forming the system of logistical multiplying factors determine the role of each of the types in the technologiacal process of distributed Multi-purpose Hubs. Methods: The assessment model for the formation of Distributed Transport Units  can be based on formal methods to predict the behavior of complex systems engineering complexes. Then one of the approaches to the solution of the problem may be the matrix method of technological factors. Results and conclusions: The proposed methodology of the selection and validation of logistic coefficients has the practical importance in the models development for assessing the condition and behavior of Distributed Transport.

  20. Modelling sequentially scored item responses

    NARCIS (Netherlands)

    Akkermans, W.

    2000-01-01

    The sequential model can be used to describe the variable resulting from a sequential scoring process. In this paper two more item response models are investigated with respect to their suitability for sequential scoring: the partial credit model and the graded response model. The investigation is c

  1. Criteria of Categorizing Logistics and Distribution Centres

    OpenAIRE

    Darko Babić; Anđelko Šćukanec; Kristijan Rogic

    2011-01-01

    Logistics and distribution centres represent very significant infrastructure elements of the macro-logistic system. The creation of the logistics and distribution centres and their connection into a wide (global) network have resulted in the creation of conditions for an adequate distribution of labour and significant increase in the productivity of all the logistics elements and processes, noting that the logistics and distribution centres in this concept have a superregional significance. ...

  2. Logistics Service Providers in the Czech Republic

    OpenAIRE

    HRNEČKOVÁ, Kateřina

    2010-01-01

    The main purpose of the thesis is to analyze the developement of providing logistics services in the Czech Republic and analyze the current situation and expected trends in the near future. The thesis presents the implementation process of logistics outsourcing and follows up the influence of the outsourcing at the level of logistics costs. Manufacturing companies see in logistics the potential tool to improve the efficiency in their operations and they include the logistics in their strategi...

  3. A Theoretic Model of Transport Logistics Demand

    OpenAIRE

    Natalija Jolić; Nikolina Brnjac; Ivica Oreb

    2006-01-01

    Concerning transport logistics as relation between transportand integrated approaches to logistics, some transport and logisticsspecialists consider the tenn tautological. However,transport is one of the components of logistics, along with inventories,resources, warehousing, infonnation and goods handling.Transport logistics considers wider commercial and operationalframeworks within which the flow of goods is plannedand managed. The demand for transport logistics services canbe valorised as ...

  4. Psychometric Consequences of Subpopulation Item Parameter Drift

    Science.gov (United States)

    Huggins-Manley, Anne Corinne

    2017-01-01

    This study defines subpopulation item parameter drift (SIPD) as a change in item parameters over time that is dependent on subpopulations of examinees, and hypothesizes that the presence of SIPD in anchor items is associated with bias and/or lack of invariance in three psychometric outcomes. Results show that SIPD in anchor items is associated…

  5. Psychometric Consequences of Subpopulation Item Parameter Drift

    Science.gov (United States)

    Huggins-Manley, Anne Corinne

    2017-01-01

    This study defines subpopulation item parameter drift (SIPD) as a change in item parameters over time that is dependent on subpopulations of examinees, and hypothesizes that the presence of SIPD in anchor items is associated with bias and/or lack of invariance in three psychometric outcomes. Results show that SIPD in anchor items is associated…

  6. Unidimensional Interpretations for Multidimensional Test Items

    Science.gov (United States)

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  7. Generalizability theory and item response theory

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.

    2012-01-01

    Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a

  8. Generalizability theory and item response theory

    NARCIS (Netherlands)

    Glas, C.A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.

    2012-01-01

    Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a s

  9. 15 CFR 742.15 - Encryption items.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Encryption items. 742.15 Section 742... BASED CONTROLS § 742.15 Encryption items. Encryption items can be used to maintain the secrecy of... export and reexport of encryption items. As the President indicated in Executive Order 13026 and in his...

  10. Item-Writing Guidelines for Physics

    Science.gov (United States)

    Regan, Tom

    2015-01-01

    A teacher learning how to write test questions (test items) will almost certainly encounter item-writing guidelines--lists of item-writing do's and don'ts. Item-writing guidelines usually are presented as applicable across all assessment settings. Table I shows some guidelines that I believe to be generally applicable and two will be briefly…

  11. Unidimensional Interpretations for Multidimensional Test Items

    Science.gov (United States)

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  12. Framework to Scope Logistics Initiatives

    CSIR Research Space (South Africa)

    Joubert, JW

    2005-07-01

    Full Text Available an initiative I Calculating stakeholder fitness I Research agenda City Logistics IV — Langkawi Johan W. Joubert — July 11, 2005 - p. 3/0 Perspective on logistics G o o d s , s e r v i c e s , a n d r e l a t e d i n f o r... m a t i o n Road Rail Air Water Pipeline N e t w o r k i n f r a s t r u c t u r e T r a n s p o r t v e h i c l e s a n d v e s s e l s N o d e i n f r a s t r u c t u r e...

  13. Optimizing sterilization logistics in hospitals.

    Science.gov (United States)

    van de Klundert, Joris; Muls, Philippe; Schadd, Maarten

    2008-03-01

    This paper deals with the optimization of the flow of sterile instruments in hospitals which takes place between the sterilization department and the operating theatre. This topic is especially of interest in view of the current attempts of hospitals to cut cost by outsourcing sterilization tasks. Oftentimes, outsourcing implies placing the sterilization unit at a larger distance, hence introducing a longer logistic loop, which may result in lower instrument availability, and higher cost. This paper discusses the optimization problems that have to be solved when redesigning processes so as to improve material availability and reduce cost. We consider changing the logistic management principles, use of visibility information, and optimizing the composition of the nets of sterile materials.

  14. Mobile Robots for Hospital Logistics

    DEFF Research Database (Denmark)

    Özkil, Ali Gürcan

    be and will be automated using mobile robots. This talk consequently addresses the key technical issues of implementing service robots in hospitals. In simple terms, a robotic system for automating hospital logistics has to be reliable, adaptable and scalable. Robots have to be semi-autonomous, and should reliably...... for localization. The system features automatic annotation, which significantly reduces manual work and offer many advantages beyond robotics. A case study on logistics solutions is finally presented. A robotic solution is tested in a hospital to handle the transportation of blood samples between the clinic...... and the lab. Without any environmental modification; it is shown that lab turnover time can be reduced from hours to minutes; by simply replacing the human porter with a mobile robot....

  15. On the Relationships between Jeffreys Modal and Weighted Likelihood Estimation of Ability under Logistic IRT Models

    Science.gov (United States)

    Magis, David; Raiche, Gilles

    2012-01-01

    This paper focuses on two estimators of ability with logistic item response theory models: the Bayesian modal (BM) estimator and the weighted likelihood (WL) estimator. For the BM estimator, Jeffreys' prior distribution is considered, and the corresponding estimator is referred to as the Jeffreys modal (JM) estimator. It is established that under…

  16. A Note on Three Statistical Tests in the Logistic Regression DIF Procedure

    Science.gov (United States)

    Paek, Insu

    2012-01-01

    Although logistic regression became one of the well-known methods in detecting differential item functioning (DIF), its three statistical tests, the Wald, likelihood ratio (LR), and score tests, which are readily available under the maximum likelihood, do not seem to be consistently distinguished in DIF literature. This paper provides a clarifying…

  17. Analysis of Cognitive Structure Using the Linear Logistic Test Model and Quadratic Assignment.

    Science.gov (United States)

    Medina-Diaz, Maria

    1993-01-01

    The cognitive structure of an algebra test was defined and validated using the linear logistic test model (LLTM) and quadratic assignment (QA). A 29-item test was administered to 235 ninth graders. Results suggest the benefits of applying both LLTM and QA to test construction and analysis. (SLD)

  18. Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

    Science.gov (United States)

    Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

    2014-01-01

    This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

  19. A Note on Three Statistical Tests in the Logistic Regression DIF Procedure

    Science.gov (United States)

    Paek, Insu

    2012-01-01

    Although logistic regression became one of the well-known methods in detecting differential item functioning (DIF), its three statistical tests, the Wald, likelihood ratio (LR), and score tests, which are readily available under the maximum likelihood, do not seem to be consistently distinguished in DIF literature. This paper provides a clarifying…

  20. Using item response theory models to evaluate the Practice Environment Scale.

    Science.gov (United States)

    Raju, Dheeraj; Su, Xiaogang; Patrician, Patricia A

    2014-01-01

    The purpose of this article is to introduce different types of item response theory models and to demonstrate their usefulness by evaluating the Practice Environment Scale. Item response theory models such as constrained and unconstrained graded response model, partial credit model, Rasch model, and one-parameter logistic model are demonstrated. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) indices are used as model selection criterion. The unconstrained graded response and partial credit models indicated the best fit for the data. Almost all items in the instrument performed well. Although most of the items strongly measure the construct, there are a few items that could be eliminated without substantially altering the instrument. The analysis revealed that the instrument may function differently when administered to different unit types.

  1. Logistic systems with linear feedback

    Science.gov (United States)

    Son, Leonid; Shulgin, Dmitry; Ogluzdina, Olga

    2016-08-01

    A wide variety of systems may be described by specific dependence, which is known as logistic curve, or S-curve, between the internal characteristic and the external parameter. Linear feedback between these two values may be suggested for a wide set of systems also. In present paper, we suggest a bifurcation behavior for systems with both features, and discuss it for two cases, which are the Ising magnet in external field, and the development of manufacturing enterprise.

  2. Multisource information fusion for logistics

    Science.gov (United States)

    Woodley, Robert; Petrov, Plamen; Noll, Warren

    2011-05-01

    Current Army logistical systems and databases contain massive amounts of data that need an effective method to extract actionable information. The databases do not contain root cause and case-based analysis needed to diagnose or predict breakdowns. A system is needed to find data from as many sources as possible, process it in an integrated fashion, and disseminate information products on the readiness of the fleet vehicles. 21st Century Systems, Inc. introduces the Agent- Enabled Logistics Enterprise Intelligence System (AELEIS) tool, designed to assist logistics analysts with assessing the availability and prognostics of assets in the logistics pipeline. AELEIS extracts data from multiple, heterogeneous data sets. This data is then aggregated and mined for data trends. Finally, data reasoning tools and prognostics tools evaluate the data for relevance and potential issues. Multiple types of data mining tools may be employed to extract the data and an information reasoning capability determines what tools are needed to apply them to extract information. This can be visualized as a push-pull system where data trends fire a reasoning engine to search for corroborating evidence and then integrate the data into actionable information. The architecture decides on what reasoning engine to use (i.e., it may start with a rule-based method, but, if needed, go to condition based reasoning, and even a model-based reasoning engine for certain types of equipment). Initial results show that AELEIS is able to indicate to the user of potential fault conditions and root-cause information mined from a database.

  3. Item Nonresponse in Face-to-Face Interviews with Children

    Directory of Open Access Journals (Sweden)

    Haunberger Sigrid

    2014-09-01

    Full Text Available This study examined item nonresponse and its respondent and interviewer correlates by means of a population-based, panel survey of children aged 8 to 11 who were surveyed using standardised, face-to-face interviews. Using multilevel, logistic analyses with cross-level interactions, this article aims to examine which effects of item nonresponse are subject to children as respondents or to the interviewers and the interview setting. Depending on the type of question, we found different effects for respondent and interviewer variables, as well as interaction effects between child age/interviewer age as well as child gender/interviewer gender. However, interviewer variance is for the most part not significant.

  4. Activities and Education in Logistics

    Directory of Open Access Journals (Sweden)

    Jasmina Pašagić Škrinjar

    2008-03-01

    Full Text Available Logistic approach to traffic means new business policy,economy and ownership, new internal organization, externaland internal communication, different corporate cultures, humanresources management using scientific methods, trainingand education, changed management type and awarding system,knowledge of information technology, communicationskills, electronic commerce, etc. Education is part of all theseelements. The introduction of logistics in all the business activitieshas been imposed due to the following reasons: because ofthe life-cycle shortening of the product and its delivery, becauseof sudden technological development, because of productionand market globalization, because of the increase in competitiveness.This paper describes first various logistic activities with theindication of practical and scientific approaches. The logisticsapproach in the traffic activities requires upgrading of the professionaland scientific level to a higher one which means additionaltraining and acquiring of new skills as well as new technologiesfor the employees.The basic aim of research was to specifY the basic logisticsactivities and problems in order to indicate the need of differentforms of education. Fast technological and social changes requireconstant improvement and modification of professionalknowledge and acqui1ing of new scientific methods and skills.

  5. The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value.

    Science.gov (United States)

    Rush, Bonnie R; Rankin, David C; White, Brad J

    2016-09-29

    Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. The mean (± SE) percent correct (83.3 % ± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 ± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice

  6. Refinement of the Brazilian Household Food Insecurity Measurement Scale: Recommendation for a 14-item EBIA

    Directory of Open Access Journals (Sweden)

    Ana Maria Segall-Corrêa

    2014-04-01

    Full Text Available OBJECTIVE: To review and refine Brazilian Household Food Insecurity Measurement Scale structure. METHODS: The study analyzed the impact of removing the item "adult lost weight" and one of two possibly redundant items on Brazilian Household Food Insecurity Measurement Scale psychometric behavior using the one-parameter logistic (Rasch model. Brazilian Household Food Insecurity Measurement Scale psychometric behavior was analyzed with respect to acceptable adjustment values ranging from 0.7 to 1.3, and to severity scores of the items with theoretically expected gradients. The socioeconomic and food security indicators came from the 2004 National Household Sample Survey, which obtained complete answers to Brazilian Household Food Insecurity Measurement Scale items from 112,665 households. RESULTS: Removing the items "adult reduced amount..." followed by "adult ate less..." did not change the infit of the remaining items, except for "adult lost weight", whose infit increased from 1.21 to 1.56. The internal consistency and item severity scores did not change when "adult ate less" and one of the two redundant items were removed. CONCLUSION: Brazilian Household Food Insecurity Measurement Scale reanalysis reduced the number of scale items from 16 to 14 without changing its internal validity. Its use as a nationwide household food security measure is strongly recommended.

  7. Logistic regression: a brief primer.

    Science.gov (United States)

    Stoltzfus, Jill C

    2011-10-01

    Regression techniques are versatile in their application to medical research because they can measure associations, predict outcomes, and control for confounding variable effects. As one such technique, logistic regression is an efficient and powerful way to analyze the effect of a group of independent variables on a binary outcome by quantifying each independent variable's unique contribution. Using components of linear regression reflected in the logit scale, logistic regression iteratively identifies the strongest linear combination of variables with the greatest probability of detecting the observed outcome. Important considerations when conducting logistic regression include selecting independent variables, ensuring that relevant assumptions are met, and choosing an appropriate model building strategy. For independent variable selection, one should be guided by such factors as accepted theory, previous empirical investigations, clinical considerations, and univariate statistical analyses, with acknowledgement of potential confounding variables that should be accounted for. Basic assumptions that must be met for logistic regression include independence of errors, linearity in the logit for continuous variables, absence of multicollinearity, and lack of strongly influential outliers. Additionally, there should be an adequate number of events per independent variable to avoid an overfit model, with commonly recommended minimum "rules of thumb" ranging from 10 to 20 events per covariate. Regarding model building strategies, the three general types are direct/standard, sequential/hierarchical, and stepwise/statistical, with each having a different emphasis and purpose. Before reaching definitive conclusions from the results of any of these methods, one should formally quantify the model's internal validity (i.e., replicability within the same data set) and external validity (i.e., generalizability beyond the current sample). The resulting logistic regression model

  8. 3PL, 4PL and insourcing logistics

    Directory of Open Access Journals (Sweden)

    Mauro Vivaldini

    2015-12-01

    Full Text Available Logistics services have evolved and changed over time, especially in the hiring of them according to the concepts of 3PL (third party logistics, 4PL (fourth party logistics or insourcing logistics. 3PL service is a consolidated business, 4PL is an option for outsourcing logistics and has already been adopted by some organizations, and insourcing logistics suggests the return of these activities being internalized by companies, which is still a relatively unexplored subject in logistics literature. Analyzing these themes in the literature, this study updates the view on them and proposes a conceptual framework that classifies the different models of logistics services, showing the different options that can be adopted to help the company decide how to run their logistics services.

  9. Construction of a two-parameter empirical model of left ventricle wall motion using cardiac tagged magnetic resonance imaging data

    Directory of Open Access Journals (Sweden)

    Shi Jack J

    2012-10-01

    the spatial and temporal evolution of the LV wall motion using a two-parameter formulation in conjunction with tMRI-based visualization of the LV wall in the transverse planes of the apex, mid-ventricle and base. In healthy hearts, the analytical model will potentially allow deriving biomechanical entities, such as strain, strain rate or torsion, which are typically used as diagnostic, prognostic or predictive markers of cardiovascular diseases including diabetes.

  10. The Life-of-Type Inventory Decision for Diminishing Manufacturing Sources Items: A Sensitivity Study.

    Science.gov (United States)

    1982-09-01

    34safety level" of stock for these items. The VSL formula used by DESC is based upon "Model IV" of Presutti and Trepp (the reader is referred to 33:248...Richard C. Trepp . "More Ado About Economic Order Quantities (EOQ)," Naval Research Logistics Quarterly, Vol. 17, No. 2 (June 1970), pp. 243-251. 34

  11. 77 FR 2278 - Waiver for Certain Defense Items Produced in the United Kingdom

    Science.gov (United States)

    2012-01-17

    ... Under Secretary of Defense (Acquisition, Technology, and Logistics) is waiving the statutory limitation... certain items to sources in the national technology and industrial base. The waiver will permit... part of the national technology and industrial base. Subsection (i) of 10 U.S.C. 2534 authorizes...

  12. 78 FR 10610 - Waiver for Certain Defense Items Produced in the United Kingdom

    Science.gov (United States)

    2013-02-14

    ... Under Secretary of Defense (Acquisition, Technology, and Logistics) is waiving the statutory limitation... procurement of certain items to sources in the national technology and industrial base. The waiver will permit... part of the national technology and industrial base. Subsection (i) of 10 U.S.C. 2534 authorizes...

  13. Fitting Item Response Theory Models to Two Personality Inventories: Issues and Insights.

    Science.gov (United States)

    Chernyshenko, Oleksandr S.; Stark, Stephen; Chan, Kim-Yin; Drasgow, Fritz; Williams, Bruce

    2001-01-01

    Compared the fit of several Item Response Theory (IRT) models to two personality assessment instruments using data from 13,059 individuals responding to one instrument and 1,770 individuals responding to the other. Two- and three-parameter logistic models fit some scales reasonably well, but not others, and the graded response model generally did…

  14. A robotic system for automation of logistics functions on the Space Station

    Science.gov (United States)

    Martin, J. C.; Purves, R. B.; Hosier, R. N.; Krein, B. A.

    1988-01-01

    Spacecraft inventory management is currently performed by the crew and as systems become more complex, increased crew time will be required to perform routine logistics activities. If future spacecraft are to function effectively as research labs and production facilities, the efficient use of crew time as a limited resource for performing mission functions must be employed. The use of automation and robotics technology, such as automated warehouse and materials handling functions, can free the crew from many logistics tasks and provide more efficient use of crew time. Design criteria for a Space Station Automated Logistics Inventory Management System is focused on through the design and demonstration of a mobile two armed terrestrial robot. The system functionally represents a 0 gravity automated inventory management system and the problems associated with operating in such an environment. Features of the system include automated storage and retrieval, item recognition, two armed robotic manipulation, and software control of all inventory item transitions and queries.

  15. A robotic system for automation of logistics functions on the Space Station

    Science.gov (United States)

    Martin, J. C.; Purves, R. B.; Hosier, R. N.; Krein, B. A.

    1988-01-01

    Spacecraft inventory management is currently performed by the crew and as systems become more complex, increased crew time will be required to perform routine logistics activities. If future spacecraft are to function effectively as research labs and production facilities, the efficient use of crew time as a limited resource for performing mission functions must be employed. The use of automation and robotics technology, such as automated warehouse and materials handling functions, can free the crew from many logistics tasks and provide more efficient use of crew time. Design criteria for a Space Station Automated Logistics Inventory Management System is focused on through the design and demonstration of a mobile two armed terrestrial robot. The system functionally represents a 0 gravity automated inventory management system and the problems associated with operating in such an environment. Features of the system include automated storage and retrieval, item recognition, two armed robotic manipulation, and software control of all inventory item transitions and queries.

  16. Combining or Separating Forward and Reverse Logistics

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel; Nielsen, Anders

    2017-01-01

    Purpose – While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine reverse logistics with forward logistics, keep the flows separated, or choose......-research addresses intra-RL issues while the relationship between forward and reverse logistics is under-researched. This paper contributes to RL-theory by identifying the contextual factors that determine the most advantageous relationship between forward and reverse logistics, and proposes a novel decision making...

  17. A Theoretic Model of Transport Logistics Demand

    Directory of Open Access Journals (Sweden)

    Natalija Jolić

    2006-01-01

    Full Text Available Concerning transport logistics as relation between transportand integrated approaches to logistics, some transport and logisticsspecialists consider the tenn tautological. However,transport is one of the components of logistics, along with inventories,resources, warehousing, infonnation and goods handling.Transport logistics considers wider commercial and operationalframeworks within which the flow of goods is plannedand managed. The demand for transport logistics services canbe valorised as highly qualitative, differentiated and derived.While researching transport phenomenon the implementationof models is inevitable and demand models highly desirable. Asa contribution to transport modelling this paper improves decisionmaking and planning in the transport logistics field.

  18. Logistics, electronic commerce, and the environment

    Science.gov (United States)

    Sarkis, Joseph; Meade, Laura; Talluri, Srinivas

    2002-02-01

    Organizations realize that a strong supporting logistics or electronic logistics (e-logistics) function is important from both commercial and consumer perspectives. The implications of e-logistics models and practices cover the forward and reverse logistics functions of organizations. They also have direct and profound impact on the natural environment. This paper will focus on a discussion of forward and reverse e-logistics and their relationship to the natural environment. After discussion of the many pertinent issues in these areas, directions of practice and implications for study and research are then described.

  19. Outsourcing of Logistics Activities in Manufacturing Industry

    Directory of Open Access Journals (Sweden)

    Anton Ogorelc

    2012-10-01

    Full Text Available The external supply of logistics se1vices is part of a trend towardoutsourcing non-core logistics activities. The scope ofthird-party logistics may range from a relatively limited combinationof activities (e.g. transportation and warehousing to acomprehensive set of logistics se1vices.The authors first discuss the characteristics of business logisticsin manufacturing indusfly, to be taken into account inlogistics outsourcing. They particularly point out the motimtionsfor logistics outsourcing, the possibilities of outsourcing,as well as supplier selection. Finally they analyze the outsourcingin the reverse logistics.

  20. The Soufriere Hills Volcano, Montserrat, is "log logistic"

    Science.gov (United States)

    Connor, C.; Sparks, S.; Mason, R.; Bonadonna, C.; Young, S.; Lejeune, A.

    2002-12-01

    The Soufriere Hills Volcano, Montserrat, experienced a remarkable episode of activity in September-October, 1997. During this period, 75 vulcanian explosions generated plumes that commonly rose between 5 to 15 km a.s.l. accompanied by pyroclastic flows. Repose intervals between vulcanian explosions varied from 2.77 to 33.7 hrs, with a median repose interval of 9.0 hr and mean of 9.6 hr. During the eruption, this narrow range of repose intervals was used in a practical way to provide qualitative forecasts of volcanic hazard. We analyzed repose intervals for these 75 vulcanian explosions and discovered they fit a log logistic distribution with > 99% confidence. This comparatively simple, two parameter model accounts for departures from a classical material failure model (Weibull distribution) at long repose intervals, and serves as the basis for improved hazard forecasts. The crucial differences between Weibull, and log logistic probability models for volcano repose interval are illustrated by comparing their hazard functions. For Weibull distributions the hazard increases indefinitely: the volcano must erupt explosively eventually and as time increases the probability of an eruption in the next time interval becomes much greater. In contrast the log logistic hazard function goes through a simple maximum. We note that largest magnitude eruptions in the time series, deduced from column height estimates and seismic explosion amplitudes, correlate with the peak in the log logistic hazard function. The excellent model fit is explained in terms of two competing processes operating in the upper conduit on different time scales. Gas bubble pressure increases with time due to exsolution and due to rheological stiffening of magma of magma following an abrupt decompression caused by a previous explosion. Once bubble gas pressure exceeds the tensile strength of the magma an explosion occurs - a material failure model that should follow a Weibull distribution. However, this

  1. Teoria da Resposta ao Item Teoria de la respuesta al item Item response theory

    Directory of Open Access Journals (Sweden)

    Eutalia Aparecida Candido de Araujo

    2009-12-01

    Full Text Available A preocupação com medidas de traços psicológicos é antiga, sendo que muitos estudos e propostas de métodos foram desenvolvidos no sentido de alcançar este objetivo. Entre os trabalhos propostos, destaca-se a Teoria da Resposta ao Item (TRI que, a princípio, veio completar limitações da Teoria Clássica de Medidas, empregada em larga escala até hoje na medida de traços psicológicos. O ponto principal da TRI é que ela leva em consideração o item particularmente, sem relevar os escores totais; portanto, as conclusões não dependem apenas do teste ou questionário, mas de cada item que o compõe. Este artigo propõe-se a apresentar esta Teoria que revolucionou a teoria de medidas.La preocupación con las medidas de los rasgos psicológicos es antigua y muchos estudios y propuestas de métodos fueron desarrollados para lograr este objetivo. Entre estas propuestas de trabajo se incluye la Teoría de la Respuesta al Ítem (TRI que, en principio, vino a completar las limitaciones de la Teoría Clásica de los Tests, ampliamente utilizada hasta hoy en la medida de los rasgos psicológicos. El punto principal de la TRI es que se tiene en cuenta el punto concreto, sin relevar las puntuaciones totales; por lo tanto, los resultados no sólo dependen de la prueba o cuestionario, sino que de cada ítem que lo compone. En este artículo se propone presentar la Teoría que revolucionó la teoría de medidas.The concern with measures of psychological traits is old and many studies and proposals of methods were developed to achieve this goal. Among these proposed methods highlights the Item Response Theory (IRT that, in principle, came to complete limitations of the Classical Test Theory, which is widely used until nowadays in the measurement of psychological traits. The main point of IRT is that it takes into account the item in particular, not relieving the total scores; therefore, the findings do not only depend on the test or questionnaire

  2. Analysis and algorithm of operating logistic expenses measuring of the universal logistic systems

    National Research Council Canada - National Science Library

    T.V. Shcholokova

    2014-01-01

    The aim of the article. The aim of the article consists in creation of technology of the logistic operations adjusting of universal logistic system functioning that is made by structural categories of logistic operating expenses...

  3. How to improve logistics customer service (LCS)?%How to improve logistics customer service (LCS) ?

    Institute of Scientific and Technical Information of China (English)

    邓姝琍

    2007-01-01

    logistics customer service (LCS) plays a very important role in logistics activity. How to improve logistics customer service (LCS)is a very urgent problem to firms. There are four solutions to solve this problem.

  4. Empirical Study of E-logistics System Based on Tibet Logistics Industry

    Institute of Scientific and Technical Information of China (English)

    Yu; LIU

    2013-01-01

    With the rapid growth of E-logistics in the global logistics industry,it is important to get insight into E-logistics system in Chinese logistics industry.Regarding the current situation of E-logistics of Chinese logistics industry,there are still many problems to be concerned and resolved.This paper will review the concepts and theoretical background of E-logistics System from previous researches.After acknowledging the essential issues on E-logistics System,a research model is designed and tested based on the Theory Acceptance Model.This research aims to provide theoretical and practical contributions for Chinese logistics companies to enhance understanding on E-logistics System.It also provides some useful theoretical implication and practical guidelines for the development of E-logistics System in Chinese logistics industry.

  5. Logistic regression for circular data

    Science.gov (United States)

    Al-Daffaie, Kadhem; Khan, Shahjahan

    2017-05-01

    This paper considers the relationship between a binary response and a circular predictor. It develops the logistic regression model by employing the linear-circular regression approach. The maximum likelihood method is used to estimate the parameters. The Newton-Raphson numerical method is used to find the estimated values of the parameters. A data set from weather records of Toowoomba city is analysed by the proposed methods. Moreover, a simulation study is considered. The R software is used for all computations and simulations.

  6. 用项目反应理论分析自陈量表时最佳模型的选择%Choice of optimal item response model for analysis of self-report questionnaire

    Institute of Scientific and Technical Information of China (English)

    周晶; 郭庆科

    2005-01-01

    评分时,其测量精度要好于2级评分,如果合并选择项,则测量精度下降.%BACKGROUND: Item response theory (IRT) is widely used in the westem world, but its use for non-cognitive measurement has been very limited in China. It is necessary to explore whether IRT is applicable in non-cognitive settings and find the optimal model.OBJECTIVE: To find the optimal IRT model for self-report questionnaire analysis with the instance of emotional competence scale (ECS) and compare the effectiveness of different models in light of model data fitting and the volume of information provision.DESIGN: A comparative study of different psychometric models tested with the same data set.SETTING: Shandong Laiwu Vocational and Technical College; Department of Psychology, Liaoning Normal University.PARTICIPANTS: Totally 617 college students of Shandong Normal University (311 males and 306 females)and 564 senior high school students of the 17 Laiwu High School (283 males and 281females) participated in the study during May 2004.METHODS: Emotional competence scale (ECS) was adopted for psychometric measurement for 5-point Likert-type items. The scale was divided into 9 subscales, namely impulse control, empathy, persistency, interpersonal intimacy, social skills, emotional regulation, emotional stability, sense of responsibility, and self-confidence. One-parameter, two-parameter and three-parameter logistic model and grade response model were used for analysis of the 9 subscales, followed by goodness of fit test (analogous to Chi-square test) and comparison of the measurement precision (reliability)of the three models.MAIN OUTCOME MEASURES: Log-likelihood ratio, average χ2 statistics and average volume of information when one-parameter, two-parameter and three-parameter Logistic model.RESULTS: Totally 1 220 questionnaires were handed out and 1 181 with valid answers were obtained. Comparison of the 3 logistic model showed that the two-parameter logistic model had the least

  7. A linear, separable two-parameter model for dual energy CT imaging of proton stopping power computation

    Energy Technology Data Exchange (ETDEWEB)

    Han, Dong, E-mail: radon.han@gmail.com; Williamson, Jeffrey F. [Medical Physics Graduate Program, Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Siebers, Jeffrey V. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 (United States)

    2016-01-15

    Purpose: To evaluate the accuracy and robustness of a simple, linear, separable, two-parameter model (basis vector model, BVM) in mapping proton stopping powers via dual energy computed tomography (DECT) imaging. Methods: The BVM assumes that photon cross sections (attenuation coefficients) of unknown materials are linear combinations of the corresponding radiological quantities of dissimilar basis substances (i.e., polystyrene, CaCl{sub 2} aqueous solution, and water). The authors have extended this approach to the estimation of electron density and mean excitation energy, which are required parameters for computing proton stopping powers via the Bethe–Bloch equation. The authors compared the stopping power estimation accuracy of the BVM with that of a nonlinear, nonseparable photon cross section Torikoshi parametric fit model (VCU tPFM) as implemented by the authors and by Yang et al. [“Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues,” Phys. Med. Biol. 55, 1343–1362 (2010)]. Using an idealized monoenergetic DECT imaging model, proton ranges estimated by the BVM, VCU tPFM, and Yang tPFM were compared to International Commission on Radiation Units and Measurements (ICRU) published reference values. The robustness of the stopping power prediction accuracy of tissue composition variations was assessed for both of the BVM and VCU tPFM. The sensitivity of accuracy to CT image uncertainty was also evaluated. Results: Based on the authors’ idealized, error-free DECT imaging model, the root-mean-square error of BVM proton stopping power estimation for 175 MeV protons relative to ICRU reference values for 34 ICRU standard tissues is 0.20%, compared to 0.23% and 0.68% for the Yang and VCU tPFM models, respectively. The range estimation errors were less than 1 mm for the BVM and Yang tPFM models, respectively. The BVM estimation accuracy is not dependent on

  8. Sharing the cost of redundant items

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moulin, Hervé

    2014-01-01

    are network connectivity problems when an existing (possibly inefficient) network must be maintained. We axiomatize a family cost ratios based on simple liability indices, one for each agent and for each item, measuring the relative worth of this item across agents, and generating cost allocation rules......We ask how to share the cost of finitely many public goods (items) among users with different needs: some smaller subsets of items are enough to serve the needs of each user, yet the cost of all items must be covered, even if this entails inefficiently paying for redundant items. Typical examples...... additive in costs....

  9. Unfair items detection in educational measurement

    CERN Document Server

    Bakman, Yefim

    2012-01-01

    Measurement professionals cannot come to an agreement on the definition of the term 'item fairness'. In this paper a continuous measure of item unfairness is proposed. The more the unfairness measure deviates from zero, the less fair the item is. If the measure exceeds the cutoff value, the item is identified as definitely unfair. The new approach can identify unfair items that would not be identified with conventional procedures. The results are in accord with experts' judgments on the item qualities. Since no assumptions about scores distributions and/or correlations are assumed, the method is applicable to any educational test. Its performance is illustrated through application to scores of a real test.

  10. Comparing the Discrete and Continuous Logistic Models

    Science.gov (United States)

    Gordon, Sheldon P.

    2008-01-01

    The solutions of the discrete logistic growth model based on a difference equation and the continuous logistic growth model based on a differential equation are compared and contrasted. The investigation is conducted using a dynamic interactive spreadsheet. (Contains 5 figures.)

  11. Logistics Clusters. Delivering Value and Driving Growth

    Directory of Open Access Journals (Sweden)

    Zoltan Kato

    2014-02-01

    Full Text Available We live in a world where the exchange of goods, information and money is achieved through complex logistic processes. The questions that the author tries to answer in his book are: What is a logistics cluster? Where are these logistics clusters formed, and where are they located? What is the difference in dynamics of the logistics clusters compared to other clusters or industrial parks? What kind of jobs exist in logistics clusters, and why the logistics clusters should be promoted and supported by authorities? How good and how reliable are these jobs? What is the environmental impact of logistics clusters? What is the role of authorities in creating successful logistics clusters and what benefits can be expected from them?

  12. A Discrete Equivalent of the Logistic Equation

    Directory of Open Access Journals (Sweden)

    Petropoulou EugeniaN

    2010-01-01

    Full Text Available A discrete equivalent and not analogue of the well-known logistic differential equation is proposed. This discrete equivalent logistic equation is of the Volterra convolution type, is obtained by use of a functional-analytic method, and is explicitly solved using the -transform method. The connection of the solution of the discrete equivalent logistic equation with the solution of the logistic differential equation is discussed. Also, some differences of the discrete equivalent logistic equation and the well-known discrete analogue of the logistic equation are mentioned. It is hoped that this discrete equivalent of the logistic equation could be a better choice for the modelling of various problems, where different versions of known discrete logistic equations are used until nowadays.

  13. Common pitfalls in statistical analysis: Logistic regression.

    Science.gov (United States)

    Ranganathan, Priya; Pramesh, C S; Aggarwal, Rakesh

    2017-01-01

    Logistic regression analysis is a statistical technique to evaluate the relationship between various predictor variables (either categorical or continuous) and an outcome which is binary (dichotomous). In this article, we discuss logistic regression analysis and the limitations of this technique.

  14. Comparing the Discrete and Continuous Logistic Models

    Science.gov (United States)

    Gordon, Sheldon P.

    2008-01-01

    The solutions of the discrete logistic growth model based on a difference equation and the continuous logistic growth model based on a differential equation are compared and contrasted. The investigation is conducted using a dynamic interactive spreadsheet. (Contains 5 figures.)

  15. Organization, Planning and Control of Marketing Logistics

    National Research Council Canada - National Science Library

    Olga V Grishchenko; Vasiliy S Kireev; Lyudmila I Dubrova; Marina B Yanenko; Ruslan Ya Vakulenko

    2016-01-01

    .... The marketing logistics as the mechanism of the marketing channel control is concentrated on integration of marketing and logistics functions while maintaining the great value of products and services...

  16. Reverse Logistics Network Structures and Design

    NARCIS (Netherlands)

    M. Fleischmann (Moritz)

    2001-01-01

    textabstractLogistics network design is commonly recognized as a strategic supply chain issue of prime importance. The location of production facilities, storage concepts, and transportation strategies are major determinants of supply chain performance. This chapter considers logistics network

  17. Reverse Logistics Network Structures and Design

    NARCIS (Netherlands)

    M. Fleischmann (Moritz)

    2001-01-01

    textabstractLogistics network design is commonly recognized as a strategic supply chain issue of prime importance. The location of production facilities, storage concepts, and transportation strategies are major determinants of supply chain performance. This chapter considers logistics network desi

  18. Transport logistics in pollen tubes.

    Science.gov (United States)

    Chebli, Youssef; Kroeger, Jens; Geitmann, Anja

    2013-07-01

    Cellular organelles move within the cellular volume and the effect of the resulting drag forces on the liquid causes bulk movement in the cytosol. The movement of both organelles and cytosol leads to an overall motion pattern called cytoplasmic streaming or cyclosis. This streaming enables the active and passive transport of molecules and organelles between cellular compartments. Furthermore, the fusion and budding of vesicles with and from the plasma membrane (exo/endocytosis) allow for transport of material between the inside and the outside of the cell. In the pollen tube, cytoplasmic streaming and exo/endocytosis are very active and fulfill several different functions. In this review, we focus on the logistics of intracellular motion and transport processes as well as their biophysical underpinnings. We discuss various modeling attempts that have been performed to understand both long-distance shuttling and short-distance targeting of organelles. We show how the combination of mechanical and mathematical modeling with cell biological approaches has contributed to our understanding of intracellular transport logistics.

  19. Management of Logistics in Modern Economic Corporation

    OpenAIRE

    Duro Horvat; Mirjana Nedovic cabarkapa

    2009-01-01

    The aim of this paper is to define the role of logistics management towards future contributions within this field, as well as a better understanding of primary approaches to logistics, shedding light on the complexity of the task which is put before logistics management these days. Logistics management is responsible for organizing and managing tasks within the sector itself, which means it is in charge of the efficiency of warehousing, efficiency in utilization of business resources, transp...

  20. The Art and Science of Defense Logistics

    Science.gov (United States)

    1995-04-01

    that military logistics must be viewed as an art, rather than a science, due to its reliance on such intangibles as intuition, morale, and innovation...completes the evolution of military logistics to scientific status through advocacy of the smart business practices of corporate logistics. The paper...consists of five topic areas: (1) a historical overview of military logistics , (2) a synopsis of the STRATPLAN, (3) a discussion of selected smart

  1. Logistics Sourcing Strategies in Supply Chain Design

    OpenAIRE

    LIU, LIWEN

    2007-01-01

    A company's logistics sourcing strategy determines whether it structures and organizeslogistics within the company or company group or integrates logistics upstream and downstreamin the supply chain. First, three different types of logistics sourcing strategies in supply chaindesign are described and the theoretical background for the development of these strategies,including both transaction cost theory and network theory, is analyzed. Two special casesabout logistics sourcing strategy decis...

  2. Logistics Performance Measurements - Issues and Reviews

    OpenAIRE

    Abu Bakar, Mohd Azlan; Jaafar, Harlina Suzana; Faisol, Nasruddin; Muhammad, Azlina

    2014-01-01

    Logistics is a backbone for the global supply chains. In Malaysia, logistics are now recognized as strategic industry that positively contribute to gross domestic product (GDP) and performance of logistics is foremost significant. Whereas most of the logistics performance has focused on investigating operational and trade facilitation contexts. Thus, the purpose of this paper is to examine the issues and reviews by practitioners and found 7 key components that translated it into operations pe...

  3. Measuring Regulatory Restrictions in Logistics Services

    OpenAIRE

    Claire HOLLWEG; Marn-Heong WONG

    2009-01-01

    This study measures the extent of restrictions on trade in logistics services in the ASEAN+6 economies by constructing a logistics regulatory restrictiveness index for each economy that quantifies the extent of government regulations faced by logistics service providers. This is the first study of its kind to construct a regulatory index of the entire logistics sector, which includes the main modes of international transport and customs restrictions. The indices show that large differences ex...

  4. Research on 6R Military Logistics Network

    Science.gov (United States)

    Jie, Wan; Wen, Wang

    The building of military logistics network is an important issue for the construction of new forces. This paper has thrown out a concept model of 6R military logistics network model based on JIT. Then we conceive of axis spoke y logistics centers network, flexible 6R organizational network, lean 6R military information network based grid. And then the strategy and proposal for the construction of the three sub networks of 6Rmilitary logistics network are given.

  5. RESEARCH OF FOREIGN EXPERIENCE OF LOGISTICS FORMATION

    Directory of Open Access Journals (Sweden)

    Starkova N. O.

    2014-05-01

    Full Text Available Objective need of Russian national logistics system formation have been substantiated. The review of global logistics infrastructure has been made as well. Characteristics of the organization and modalities of logistics systems of leading foreign countries have been researched. On the basis of summarizing foreign experience we have made conclusions about the possibility of its use in the development of the domestic logistic model

  6. Green Logistics Qualifikation in der Logistikpraxis

    OpenAIRE

    Keuschen, Thomas; Klumpp, Matthias

    2011-01-01

    Sustainability trends are to be found in logistics today as green logistics or product - respectively company - carbon footprints. Within this evolving field of logistics several research areas are developing such as CO2 measurement standardization, integrated management concepts and process changes in relation to the implementation of new transport mode and propulsion systems in cargo transport. But one major hurdle for the further implementation of green logistics concepts is the existing q...

  7. Differential Item Functioning (DIF) among Spanish-Speaking English Language Learners (ELLs) in State Science Tests

    Science.gov (United States)

    Ilich, Maria O.

    Psychometricians and test developers evaluate standardized tests for potential bias against groups of test-takers by using differential item functioning (DIF). English language learners (ELLs) are a diverse group of students whose native language is not English. While they are still learning the English language, they must take their standardized tests for their school subjects, including science, in English. In this study, linguistic complexity was examined as a possible source of DIF that may result in test scores that confound science knowledge with a lack of English proficiency among ELLs. Two years of fifth-grade state science tests were analyzed for evidence of DIF using two DIF methods, Simultaneous Item Bias Test (SIBTest) and logistic regression. The tests presented a unique challenge in that the test items were grouped together into testlets---groups of items referring to a scientific scenario to measure knowledge of different science content or skills. Very large samples of 10, 256 students in 2006 and 13,571 students in 2007 were examined. Half of each sample was composed of Spanish-speaking ELLs; the balance was comprised of native English speakers. The two DIF methods were in agreement about the items that favored non-ELLs and the items that favored ELLs. Logistic regression effect sizes were all negligible, while SIBTest flagged items with low to high DIF. A decrease in socioeconomic status and Spanish-speaking ELL diversity may have led to inconsistent SIBTest effect sizes for items used in both testing years. The DIF results for the testlets suggested that ELLs lacked sufficient opportunity to learn science content. The DIF results further suggest that those constructed response test items requiring the student to draw a conclusion about a scientific investigation or to plan a new investigation tended to favor ELLs.

  8. Trans-theta logistics: a new family of population growth sigmoid functions.

    Science.gov (United States)

    Kozusko, F; Bourdeau, M

    2011-12-01

    Sigmoid functions have been applied in many areas to model self limited population growth. The most popular functions; General Logistic (GL), General von Bertalanffy (GV), and Gompertz (G), comprise a family of functions called Theta Logistic ([Formula: see text] L). Previously, we introduced a simple model of tumor cell population dynamics which provided a unifying foundation for these functions. In the model the total population (N) is divided into reproducing (P) and non-reproducing/quiescent (Q) sub-populations. The modes of the rate of change of ratio P/N was shown to produce GL, GV or G growth. We now generalize the population dynamics model and extend the possible modes of the P/N rate of change. We produce a new family of sigmoid growth functions, Trans-General Logistic (TGL), Trans-General von Bertalanffy (TGV) and Trans-Gompertz (TG)), which as a group we have named Trans-Theta Logistic (T [Formula: see text] L) since they exist when the [Formula: see text] L are translated from a two parameter into a three parameter phase space. Additionally, the model produces a new trigonometric based sigmoid (TS). The [Formula: see text] L sigmoids have an inflection point size fixed by a single parameter and an inflection age fixed by both of the defining parameters. T [Formula: see text] L and TS sigmoids have an inflection point size defined by two parameters in bounding relationships and inflection point age defined by three parameters (two bounded). While the Theta Logistic sigmoids provided flexibility in defining the inflection point size, the Trans-Theta Logistic sigmoids provide flexibility in defining the inflection point size and age. By matching the slopes at the inflection points we compare the range of values of inflection point age for T [Formula: see text] L versus [Formula: see text] L for model growth curves.

  9. Research of Logistics Cost Based on Saving Algorithm: A Case of A Certain Logistics Company’s Logistics Cost

    Directory of Open Access Journals (Sweden)

    Nie Jing

    2016-01-01

    Full Text Available In recent years, logistics companies of different sizes has been considerably developed all over the country, with the intensified competitions. To stand out in the competitive market, a logistics company must improve its logistics situation, focus on the function of distribution center, reduce logistics costs for enhancing the impact of supply chain, and rapidly response to customer needs. Thus, how to better design or optimize the existing distribution route for reducing logistics costs becomes a difficult problem, and this article will do some researches on it.

  10. A Bifactor Multidimensional Item Response Theory Model for Differential Item Functioning Analysis on Testlet-Based Items

    Science.gov (United States)

    Fukuhara, Hirotaka; Kamata, Akihito

    2011-01-01

    A differential item functioning (DIF) detection method for testlet-based data was proposed and evaluated in this study. The proposed DIF model is an extension of a bifactor multidimensional item response theory (MIRT) model for testlets. Unlike traditional item response theory (IRT) DIF models, the proposed model takes testlet effects into…

  11. Cooperative Sustainment: A Strategy for Focused Logistics.

    Science.gov (United States)

    2007-11-02

    sustainment challenges. This paper discusses the growing similarity between commercial and military logistics and identifies key commercial logistic...capabilities that will have to be fused into military logistics planning in order to meet the diverse range of missions expected in the post cold war era.

  12. Logistics potentials in business competitive advantage creation

    Directory of Open Access Journals (Sweden)

    Rafał Matwiejczuk

    2013-12-01

    Full Text Available Background: Companies constantly search for ways to achieve and sustain long-term competitive advantage. Among the factors influencing the competitive advantage creation there are so called logistics potentials, which constitute a component part of a business strategic potentials. Logistics resources, logistics capabilities and logistics competences are the main components of the logistics potentials structure and hierarchy. Methods: In order to recognize the logistics potentials which determine the competitive advantage creation one may use the assumptions and elements of contemporary management concepts, including strategic management. In particular the article deals with Resource-Based View (RBV, Dynamic Capabilities Concept (DCC and - first of all - Competence-Based Management (CBM. Results and conclusions: Several significant research projects have presented a wide scope and a large number of possibilities of logistics potentials (and logistics competences in particular influence on business competitive advantage creation. The article briefly presents the research results conducted by: (1 Michigan State University (USA, (2 European Logistics Association (ELA in cooperation with A.T. Kearney, (3 Computer Sciences Corporation and (4 Capgemini. The research results have pointed out to differentiated but at the same distinctive symptoms of logistics competences influence on competitive advantage creation. The article also refers to the results of the research carried out by the Chair of Logistics & Marketing at Opole University (Poland in companies operating in Poland. The research has been mainly dealing with the significance of logistics competences in competitive advantage creation.

  13. APPROACHING DEVELOPMENT IN LOGISTIC INFORMATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Louis F Buys

    2012-01-01

    Full Text Available The introduction of technology into modern defence necessitates integrated computerized information systems to render effective and efficient logistic support. Traditional information system development does not ensure attainment of use and time scale requirements in the continuously developing environment of logistics. This paper describes current approaches to the development of logistic information systems.

  14. Social logistics –paths of development

    Directory of Open Access Journals (Sweden)

    P. Kolodziejczyk

    2011-01-01

    Full Text Available The paper aims to introduce discussion about a new domain of practical application of logistics the social logistics, which is the third part (after militaristic and commercial needed for a full view of the contemporary logistics application possibilities.

  15. Controlling Type I Error Rates in Assessing DIF for Logistic Regression Method Combined with SIBTEST Regression Correction Procedure and DIF-Free-Then-DIF Strategy

    Science.gov (United States)

    Shih, Ching-Lin; Liu, Tien-Hsiang; Wang, Wen-Chung

    2014-01-01

    The simultaneous item bias test (SIBTEST) method regression procedure and the differential item functioning (DIF)-free-then-DIF strategy are applied to the logistic regression (LR) method simultaneously in this study. These procedures are used to adjust the effects of matching true score on observed score and to better control the Type I error…

  16. Controlling Type I Error Rates in Assessing DIF for Logistic Regression Method Combined with SIBTEST Regression Correction Procedure and DIF-Free-Then-DIF Strategy

    Science.gov (United States)

    Shih, Ching-Lin; Liu, Tien-Hsiang; Wang, Wen-Chung

    2014-01-01

    The simultaneous item bias test (SIBTEST) method regression procedure and the differential item functioning (DIF)-free-then-DIF strategy are applied to the logistic regression (LR) method simultaneously in this study. These procedures are used to adjust the effects of matching true score on observed score and to better control the Type I error…

  17. Using automatic item generation to create multiple-choice test items.

    Science.gov (United States)

    Gierl, Mark J; Lai, Hollis; Turner, Simon R

    2012-08-01

    Many tests of medical knowledge, from the undergraduate level to the level of certification and licensure, contain multiple-choice items. Although these are efficient in measuring examinees' knowledge and skills across diverse content areas, multiple-choice items are time-consuming and expensive to create. Changes in student assessment brought about by new forms of computer-based testing have created the demand for large numbers of multiple-choice items. Our current approaches to item development cannot meet this demand. We present a methodology for developing multiple-choice items based on automatic item generation (AIG) concepts and procedures. We describe a three-stage approach to AIG and we illustrate this approach by generating multiple-choice items for a medical licensure test in the content area of surgery. To generate multiple-choice items, our method requires a three-stage process. Firstly, a cognitive model is created by content specialists. Secondly, item models are developed using the content from the cognitive model. Thirdly, items are generated from the item models using computer software. Using this methodology, we generated 1248 multiple-choice items from one item model. Automatic item generation is a process that involves using models to generate items using computer technology. With our method, content specialists identify and structure the content for the test items, and computer technology systematically combines the content to generate new test items. By combining these outcomes, items can be generated automatically. © Blackwell Publishing Ltd 2012.

  18. Item calibration in incomplete testing designs

    NARCIS (Netherlands)

    Eggen, Theo J.H.M.; Verhelst, Norman D.

    2011-01-01

    This study discusses the justifiability of item parameter estimation in incomplete testing designs in item response theory. Marginal maximum likelihood (MML) as well as conditional maximum likelihood (CML) procedures are considered in three commonly used incomplete designs: random incomplete, multis

  19. Environmental costs and reverse logistics: a systemic analysis

    Directory of Open Access Journals (Sweden)

    Paula de Souza

    2013-08-01

    Full Text Available This article aims to analyze the articles most relevant to the themes inherent environmental costs from the perspective of reverse logistics, identifying gaps for these two approaches through systemic analysis. In order to achieve the purpose of this article, the intervention instrument used was ProKnow-C (Knowledge Process Development - Constructivist. The application of this methodology resulted in gross bank of articles, comprising 1225 items obtained from four international databases: Science Direct, ISI Web of Science, Scopus and Wiley Online Library. The raw bank was filtered in relation to redundancy, the alignment of the title and the scientific relevance. The filtering had resulted in a set of 15 articles aligned with two axes of research. The analysis of the selected articles identified the most cited article and the author most cited, concluding that the issue environmental costs associated with reverse logistics is studied by several authors and universities. Moreover, it was found that the keyword most presented in the articles was reverse logistics. The analysis of 1117 references of the 15 articles has shown the most cited articles, as well as the most countrast journals and academic relevance of authors and their selected articles. A systemic analysis of the 15 selected articles showed that the two lines of research are related mainly to issues of environmental sustainability, competitiveness and business efficiency.

  20. Development of a hospital mobile platform for logistics tasks

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Acosta Calderon

    2015-04-01

    Full Text Available Healthcare services heavily rely on healthcare staff and subsequently, there is the need to improve healthcare staff׳s workflow. The deployment of an automated mobile base will help enhance the productivity of logistics tasks in the hospital, like collection and delivery. By improving such logistic tasks healthcare personal is able to focus on other tasks to serve the community better. Currently there are commercial solutions to deal with these logistic tasks, where a mobile base is able to move from one place to another in a structured environment like a hospital. In this paper, we present our approach to develop a cost effective mobile base to be used for delivery in healthcare amenities. The proposed approach is able to navigate among stations in the hospital by first creating a map of the floor and then indicating the location of these stations. This reduces the additional cost of drawing lines on the floor or to put laser markers and many of the commercial solutions required. In addition, the proposed solution is able to navigate while being safe for the people moving around and to the transported items. The paper discusses the design consideration of the system, the navigation and the battery management to ensure that the system is able to run autonomously without the need recharge often.

  1. The promise and challenge of including multimedia items in medical licensure examinations: some insights from an empirical trial.

    Science.gov (United States)

    Shen, Linjun; Li, Feiming; Wattleworth, Roberta; Filipetto, Frank

    2010-10-01

    The Comprehensive Osteopathic Medical Licensing Examination conducted a trial of multimedia items in the 2008-2009 Level 3 testing cycle to determine (1) if multimedia items were able to test additional elements of medical knowledge and skills and (2) how to develop effective multimedia items. Forty-four content-matched multimedia and text multiple-choice items were randomly delivered to Level 3 candidates. Logistic regression and paired-samples t tests were used for pairwise and group-level comparisons, respectively. Nine pairs showed significant differences in either difficulty or/and discrimination. Content analysis found that, if text narrations were less direct, multimedia materials could make items easier. When textbook terminologies were replaced by multimedia presentations, multimedia items could become more difficult. Moreover, a multimedia item was found not uniformly difficult for candidates at different ability levels, possibly because multimedia and text items tested different elements of a same concept. Multimedia items may be capable of measuring some constructs different from what text items can measure. Effective multimedia items with reasonable psychometric properties can be intentionally developed.

  2. Processing Polarity Items: Contrastive Licensing Costs

    Science.gov (United States)

    Saddy, Douglas; Drenhaus, Heiner; Frisch, Stefan

    2004-01-01

    We describe an experiment that investigated the failure to license polarity items in German using event-related brain potentials (ERPs). The results reveal distinct processing reflexes associated with failure to license positive polarity items in comparison to failure to license negative polarity items. Failure to license both negative and…

  3. Towards an authoring system for item construction

    NARCIS (Netherlands)

    Rikers, Jos H.A.N.

    1988-01-01

    The process of writing test items is analyzed, and a blueprint is presented for an authoring system for test item writing to reduce invalidity and to structure the process of item writing. The developmental methodology is introduced, and the first steps in the process are reported. A historical revi

  4. Generalized Full-Information Item Bifactor Analysis

    Science.gov (United States)

    Cai, Li; Yang, Ji Seung; Hansen, Mark

    2011-01-01

    Full-information item bifactor analysis is an important statistical method in psychological and educational measurement. Current methods are limited to single-group analysis and inflexible in the types of item response models supported. We propose a flexible multiple-group item bifactor analysis framework that supports a variety of…

  5. Real and Artificial Differential Item Functioning

    Science.gov (United States)

    Andrich, David; Hagquist, Curt

    2012-01-01

    The literature in modern test theory on procedures for identifying items with differential item functioning (DIF) among two groups of persons includes the Mantel-Haenszel (MH) procedure. Generally, it is not recognized explicitly that if there is real DIF in some items which favor one group, then as an artifact of this procedure, artificial DIF…

  6. Item Response Methods for Educational Assessment.

    Science.gov (United States)

    Mislevy, Robert J.; Rieser, Mark R.

    Multiple matrix sampling (MMS) theory indicates how data may be gathered to most efficiently convey information about levels of attainment in a population, but standard analyses of these data require random sampling of items from a fixed pool of items. This assumption proscribes the retirement of flawed or obsolete items from the pool as well as…

  7. Matrix Sampling of Test Items. ERIC Digest.

    Science.gov (United States)

    Childs, Ruth A.; Jaciw, Andrew P.

    This Digest describes matrix sampling of test items as an approach to achieving broad coverage while minimizing testing time per student. Matrix sampling involves developing a complete set of items judged to cover the curriculum, then dividing the items into subsets and administering one subset to each student. Matrix sampling, by limiting the…

  8. The Multidimensionality of Verbal Analogy Items

    Science.gov (United States)

    Ullstadius, Eva; Carlstedt, Berit; Gustafsson, Jan-Eric

    2008-01-01

    The influence of general and verbal ability on each of 72 verbal analogy test items were investigated with new factor analytical techniques. The analogy items together with the Computerized Swedish Enlistment Battery (CAT-SEB) were given randomly to two samples of 18-year-old male conscripts (n = 8566 and n = 5289). Thirty-two of the 72 items had…

  9. Analyzing the Efficient Execution of In-Store Logistics Processes in Grocery Retailing

    DEFF Research Database (Denmark)

    Reiner, Gerald; Teller, Christop; Kotzab, Herbert

    2013-01-01

    In this article, we examine in-store logistics processes for handling dairy products, from the incoming dock to the shelves of supermarkets and hypermarkets. The efficient execution of the in-store logistics related to such fast-moving, sensitive, and essential items is challenging and crucial...... for grocery retailers' sales, profits, and image. In our empirical study, we survey in-store logistics processes in 202 grocery supermarkets and hypermarkets belonging to a major retail chain in central Europe. Using a data envelopment analysis (DEA) and simulation, we facilitate process benchmarking....... In particular, we identify ways of improving in-store logistics processes by showing the performance impacts of different managerial strategies and tactics. The DEA results indicate different efficiency levels for different store formats; the hybrid store format of the small hypermarket exhibits a comparatively...

  10. Optimal item pool design for computerized adaptive tests with polytomous items using GPCM

    Directory of Open Access Journals (Sweden)

    Xuechun Zhou

    2014-09-01

    Full Text Available Computerized adaptive testing (CAT is a testing procedure with advantages in improving measurement precision and increasing test efficiency. An item pool with optimal characteristics is the foundation for a CAT program to achieve those desirable psychometric features. This study proposed a method to design an optimal item pool for tests with polytomous items using the generalized partial credit model (G-PCM. It extended a method for approximating optimality with polytomous items being described succinctly for the purpose of pool design. Optimal item pools were generated using CAT simulations with and without practical constraints of content balancing and item exposure control. The performances of the item pools were evaluated against an operational item pool. The results indicated that the item pools designed with stratification based on discrimination parameters performed well with an efficient use of the less discriminative items within the target accuracy levels. The implications for developing item pools are also discussed.

  11. Emergency Power For Critical Items

    Science.gov (United States)

    Young, William R.

    2009-07-01

    Natural disasters, such as hurricanes, floods, tornados, and tsunami, are becoming a greater problem as climate change impacts our environment. Disasters, whether natural or man made, destroy lives, homes, businesses and the natural environment. Such disasters can happen with little or no warning, leaving hundreds or even thousands of people without medical services, potable water, sanitation, communications and electrical services for up to several weeks. In our modern world, the need for electricity has become a necessity. Modern building codes and new disaster resistant building practices are reducing the damage to homes and businesses. Emergency gasoline and diesel generators are becoming common place for power outages. Generators need fuel, which may not be available after a disaster, but Photovoltaic (solar-electric) systems supply electricity without petroleum fuel as they are powered by the sun. Photovoltaic (PV) systems can provide electrical power for a home or business. PV systems can operate as utility interactive or stand-alone with battery backup. Determining your critical load items and sizing the photovoltaic system for those critical items, guarantees their operation in a disaster.

  12. Intact Transition Epitope Mapping (ITEM)

    Science.gov (United States)

    Yefremova, Yelena; Opuni, Kwabena F. M.; Danquah, Bright D.; Thiesen, Hans-Juergen; Glocker, Michael O.

    2017-08-01

    Intact transition epitope mapping (ITEM) enables rapid and accurate determination of protein antigen-derived epitopes by either epitope extraction or epitope excision. Upon formation of the antigen peptide-containing immune complex in solution, the entire mixture is electrosprayed to translate all constituents as protonated ions into the gas phase. There, ions from antibody-peptide complexes are separated from unbound peptide ions according to their masses, charges, and shapes either by ion mobility drift or by quadrupole ion filtering. Subsequently, immune complexes are dissociated by collision induced fragmentation and the ion signals of the "complex-released peptides," which in effect are the epitope peptides, are recorded in the time-of-flight analyzer of the mass spectrometer. Mixing of an antibody solution with a solution in which antigens or antigen-derived peptides are dissolved is, together with antigen proteolysis, the only required in-solution handling step. Simplicity of sample handling and speed of analysis together with very low sample consumption makes ITEM faster and easier to perform than other experimental epitope mapping methods.

  13. Country logistics performance and disaster impact.

    Science.gov (United States)

    Vaillancourt, Alain; Haavisto, Ira

    2016-04-01

    The aim of this paper is to deepen the understanding of the relationship between country logistics performance and disaster impact. The relationship is analysed through correlation analysis and regression models for 117 countries for the years 2007 to 2012 with disaster impact variables from the International Disaster Database (EM-DAT) and logistics performance indicators from the World Bank. The results show a significant relationship between country logistics performance and disaster impact overall and for five out of six specific logistic performance indicators. These specific indicators were further used to explore the relationship between country logistic performance and disaster impact for three specific disaster types (epidemic, flood and storm). The findings enhance the understanding of the role of logistics in a humanitarian context with empirical evidence of the importance of country logistics performance in disaster response operations.

  14. 3PL Services in City Logistics

    DEFF Research Database (Denmark)

    Aastrup, Jesper; Gammelgaard, Britta; Prockl, Günter

    2012-01-01

    The purpose of this paper is 1) to develop an overview of activities and services that can add value for users and consignees in city logistics schemes based on Urban Consolidation Centre, and 2) to understand and analyze the perceived value for users and consignees from using such services....... The paper will be based on studies of the city logistics literature and existing city logistics schemes, as well as survey and interview findings from studies of potential users (retailers) in Copenhagen inner city and interviews with existing users (retailers) of existing city logistics services...... in the cities of Maastricht, Netherlands, and Hasselt, Belgium. The paper provides an overview and classification of possible third party logistics services in city logistics schemes. Also, findings about value perceived by current users as well as potential users are presented. Literature on city logistics has...

  15. Expected linking error resulting from item parameter drift among the common Items on Rasch calibrated tests.

    Science.gov (United States)

    Miller, G Edward; Gesn, Paul Randall; Rotou, Jourania

    2005-01-01

    In state assessment programs that employ Rasch-based common item linking procedures, the linking constant is usually estimated with only those common items not identified as exhibiting item difficulty parameter drift. Since state assessments typically contain a fixed number of items, an item classified as exhibiting parameter drift during the linking process remains on the exam as a scorable item even if it is removed from the common item set. Under the assumption that item parameter drift has occurred for one or more of the common items, the expected effect of including or excluding the "affected" item(s) in the estimation of the linking constant is derived in this article. If the item parameter drift is due solely to factors not associated with a change in examinee achievement, no linking error will (be expected to) occur given that the linking constant is estimated only with the items not identified as "affected"; linking error will (be expected to) occur if the linking constant is estimated with all common items. However, if the item parameter drift is due solely to change in examinee achievement, the opposite is true: no linking error will (be expected to) occur if the linking constant is estimated with all common items; linking error will (be expected to) occur if the linking constant is estimated only with the items not identified as "affected".

  16. Approximation Preserving Reductions among Item Pricing Problems

    Science.gov (United States)

    Hamane, Ryoso; Itoh, Toshiya; Tomita, Kouhei

    When a store sells items to customers, the store wishes to determine the prices of the items to maximize its profit. Intuitively, if the store sells the items with low (resp. high) prices, the customers buy more (resp. less) items, which provides less profit to the store. So it would be hard for the store to decide the prices of items. Assume that the store has a set V of n items and there is a set E of m customers who wish to buy those items, and also assume that each item i ∈ V has the production cost di and each customer ej ∈ E has the valuation vj on the bundle ej ⊆ V of items. When the store sells an item i ∈ V at the price ri, the profit for the item i is pi = ri - di. The goal of the store is to decide the price of each item to maximize its total profit. We refer to this maximization problem as the item pricing problem. In most of the previous works, the item pricing problem was considered under the assumption that pi ≥ 0 for each i ∈ V, however, Balcan, et al. [In Proc. of WINE, LNCS 4858, 2007] introduced the notion of “loss-leader, ” and showed that the seller can get more total profit in the case that pi < 0 is allowed than in the case that pi < 0 is not allowed. In this paper, we derive approximation preserving reductions among several item pricing problems and show that all of them have algorithms with good approximation ratio.

  17. Chaotic processes using the two-parameter derivative with non-singular and non-local kernel: Basic theory and applications.

    Science.gov (United States)

    Doungmo Goufo, Emile Franc

    2016-08-01

    After having the issues of singularity and locality addressed recently in mathematical modelling, another question regarding the description of natural phenomena was raised: How influent is the second parameter β of the two-parameter Mittag-Leffler function Eα,β(z), z∈ℂ? To answer this question, we generalize the newly introduced one-parameter derivative with non-singular and non-local kernel [A. Atangana and I. Koca, Chaos, Solitons Fractals 89, 447 (2016); A. Atangana and D. Bealeanu (e-print)] by developing a similar two-parameter derivative with non-singular and non-local kernel based on Eα , β(z). We exploit the Agarwal/Erdelyi higher transcendental functions together with their Laplace transforms to explicitly establish the Laplace transform's expressions of the two-parameter derivatives, necessary for solving related fractional differential equations. Explicit expression of the associated two-parameter fractional integral is also established. Concrete applications are done on atmospheric convection process by using Lorenz non-linear simple system. Existence result for the model is provided and a numerical scheme established. As expected, solutions exhibit chaotic behaviors for α less than 0.55, and this chaos is not interrupted by the impact of β. Rather, this second parameter seems to indirectly squeeze and rotate the solutions, giving an impression of twisting. The whole graphics seem to have completely changed its orientation to a particular direction. This is a great observation that clearly shows the substantial impact of the second parameter of Eα , β(z), certainly opening new doors to modeling with two-parameter derivatives.

  18. Losing Items in the Psychogeriatric Nursing Home

    Directory of Open Access Journals (Sweden)

    J. van Hoof PhD

    2016-09-01

    Full Text Available Introduction: Losing items is a time-consuming occurrence in nursing homes that is ill described. An explorative study was conducted to investigate which items got lost by nursing home residents, and how this affects the residents and family caregivers. Method: Semi-structured interviews and card sorting tasks were conducted with 12 residents with early-stage dementia and 12 family caregivers. Thematic analysis was applied to the outcomes of the sessions. Results: The participants stated that numerous personal items and assistive devices get lost in the nursing home environment, which had various emotional, practical, and financial implications. Significant amounts of time are spent on trying to find items, varying from 1 hr up to a couple of weeks. Numerous potential solutions were identified by the interviewees. Discussion: Losing items often goes together with limitations to the participation of residents. Many family caregivers are reluctant to replace lost items, as these items may get lost again.

  19. Instructional Topics in Educational Measurement (ITEMS) Module: Using Automated Processes to Generate Test Items

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis

    2013-01-01

    Changes to the design and development of our educational assessments are resulting in the unprecedented demand for a large and continuous supply of content-specific test items. One way to address this growing demand is with automatic item generation (AIG). AIG is the process of using item models to generate test items with the aid of computer…

  20. System evaluation of logistics performance: Proposal for a supply network in a Public Higher Education Institution

    Directory of Open Access Journals (Sweden)

    Alberto de Oliveira Cardoso Neto

    2017-06-01

    Full Text Available The recent quest for efficiency in public companies in Brazil was one of the motives to elaborate this paper, which had a public Institution of Higher Education (IHE as its subject of study. The IHE profiled possesses a multi-campus structure and the distribution of its consumer items is performed by the institution’s own warehouse. Through field research, it became apparent that the supply of these items had some problems, such as items out of stock, orders with delayed delivery, items past their shelf life etc. Therefore, this paper article aimed to propose an evaluation system of the logistical services at the IHE studied, based on performance indicators developed from mangers’ perceptions about the problems occurring in the distribution of consumer items. In addition, an index, calculated from diverse indicators, was proposed which would be able to express the performance of the logistics service of the IHE studied, and reflect the perceptions of the main users of this service. It is understood that the solution proposed here can be applied to any two-echelon supply network.

  1. Criteria of Categorizing Logistics and Distribution Centres

    Directory of Open Access Journals (Sweden)

    Darko Babić

    2011-07-01

    Full Text Available Logistics and distribution centres represent very significant infrastructure elements of the macro-logistic system. The creation of the logistics and distribution centres and their connection into a wide (global network have resulted in the creation of conditions for an adequate distribution of labour and significant increase in the productivity of all the logistics elements and processes, noting that the logistics and distribution centres in this concept have a superregional significance. This paper represents the summary (results of the research that was carried out on a large number of logistics and distribution centres with the aim of considering the complexity and the issues related to the logistics and distribution centres and the distribution network, their elements and action of the subsystems according to the following criteria: spatial, technical, technological, and organizational, with the aim of defining the categorisation model of the logistics and distribution centres. The analysis of the selected data collected during the research has resulted in defining of the categorisation model of the logistics and distribution centres which foresees six categories. Each of the foreseen categories has been defined according to the set model by the mentioned traffic, technical and technological, and organisational characteristics and the level of service. This is precisely where the application of the categorisation model of the logistics and distribution centres can be found, which will define the relevant categories of the centres applicable in the creation of effective distribution

  2. Assessing the National Logistics System of Vietnam

    Directory of Open Access Journals (Sweden)

    Ruth Banomyong

    2015-03-01

    Full Text Available The purpose of this research is to present and analyse the current situation regarding the capability of the national logistics system in Vietnam. A national assessment framework for macro-logistics is utilised in combination with semi-structured interviews of key Vietnamese stakeholders to reflect on the current situation in the country. There are still numerous shortcomings in the Vietnamese logistics system. These shortcomings are not purely infrastructure based but also from a regulatory and commercial perspective. The presented national logistics system assessment framework can be replicated in other countries or regions when assessing national logistics capability. The findings can help foreign investors, international logistics providers wanting to provide their services in Vietnam to understand the logistics context within the country. These findings are also helpful for policy makers in Vietnam on how to improve their national logistics system. This study proposes a template to assess national logistics systems and provides an in-depth understanding of logistics in Vietnam, a country that has not been much studied in the literature.

  3. New technologies for item monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, J.A. [EG & G Energy Measurements, Albuquerque, NM (United States); Waddoups, I.G. [Sandia National Labs., Albuquerque, NM (United States)

    1993-12-01

    This report responds to the Department of Energy`s request that Sandia National Laboratories compare existing technologies against several advanced technologies as they apply to DOE needs to monitor the movement of material, weapons, or personnel for safety and security programs. The authors describe several material control systems, discuss their technologies, suggest possible applications, discuss assets and limitations, and project costs for each system. The following systems are described: WATCH system (Wireless Alarm Transmission of Container Handling); Tag system (an electrostatic proximity sensor); PANTRAK system (Personnel And Material Tracking); VRIS (Vault Remote Inventory System); VSIS (Vault Safety and Inventory System); AIMS (Authenticated Item Monitoring System); EIVS (Experimental Inventory Verification System); Metrox system (canister monitoring system); TCATS (Target Cueing And Tracking System); LGVSS (Light Grid Vault Surveillance System); CSS (Container Safeguards System); SAMMS (Security Alarm and Material Monitoring System); FOIDS (Fiber Optic Intelligence & Detection System); GRADS (Graded Radiation Detection System); and PINPAL (Physical Inventory Pallet).

  4. Key aspects of logistics services audit

    Directory of Open Access Journals (Sweden)

    N.V. Gaidabrus

    2015-06-01

    Full Text Available The aim of the article. Aim of the article is to characterize the logistics audit essence, to form main stages of the logistic service audit and to observe informational providing of these stages, to characterize behavior model concerning logistic service factors analysis. The results of the analysis. The given work deals with logistic audit value and its essence, which is determined as representing sources of the spare logistic expenses and investigates plan for further actions concerning development or withdrawal of the logistic service components in order to find optimal ratio between its level and proper expenses. Also the main stages of logistic service audit are provided as following: collection and processing information, which is necessary to calculate logistic service estimation factors; estimation the logistic service real state; creation factors positions trimeric matrix for logistic service estimation; determination the logistic service factors, requiring fast development or immediate leaving; searching optimal level of expenses for logistic service considering its desirable level. Also informational support of these stages is provided in the article, which includes internal reporting of the enterprise: financial and statistic reporting data; personal observation and market study data, analytics, results of the experts’ evaluations; factors of the logistic service and costs for their support or improvement; factors positions trimeric matrix for logistic service estimation. Also author characterizes in details behavior model concerning logistic service factors analysis, which includes trimeric decision making matrix. Having analyzed the matrix, one may define which elements of the logistic service are necessary to move, develop or support immediately or gradually. All factors on the matrix are located by three axes: logistic service element of the estimation factor weight (it takes the value 0-1; estimation of the logistic service

  5. Biomass Supply Logistics and Infrastructure

    Science.gov (United States)

    Sokhansanj, Shahabaddine; Hess, J. Richard

    Feedstock supply system encompasses numerous unit operations necessary to move lignocellulosic feedstock from the place where it is produced (in the field or on the stump) to the start of the conversion process (reactor throat) of the biorefinery. These unit operations, which include collection, storage, preprocessing, handling, and transportation, represent one of the largest technical and logistics challenges to the emerging lignocellulosic biorefining industry. This chapter briefly reviews the methods of estimating the quantities of biomass, followed by harvesting and collection processes based on current practices on handling wet and dry forage materials. Storage and queuing are used to deal with seasonal harvest times, variable yields, and delivery schedules. Preprocessing can be as simple as grinding and formatting the biomass for increased bulk density or improved conversion efficiency, or it can be as complex as improving feedstock quality through fractionation, tissue separation, drying, blending, and densification. Handling and transportation consists of using a variety of transport equipment (truck, train, ship) for moving the biomass from one point to another. The chapter also provides typical cost figures for harvest and processing of biomass.

  6. Container Logistic Transport Planning Model

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2013-05-01

    Full Text Available The study proposed a stochastic method of container logistic transport in order to solve the unreasonable transportation’s problem and overcome the traditional models’ two shortcomings. Container transport has rapidly developed into a modern means of transportation because of their significant advantages. With the development, it also exacerbated the flaws of transport in the original. One of the most important problems was that the invalid transport had not still reduced due to the congenital imbalances of transportation. Container transport exacerbated the invalid transport for the empty containers. To solve the problem, people made many efforts, but they did not make much progress. There had two theoretical flaws by analyzing the previous management methods in container transport. The first one was the default empty containers inevitability. The second one was that they did not overall consider how to solve the problem of empty containers allocation. In order to solve the unreasonable transportation’s problem and overcome the traditional models’ two shortcomings, the study re-built the container transport planning model-gravity model. It gave the general algorithm and has analyzed the final result of model.

  7. Biomass supply logistics and infrastructure.

    Science.gov (United States)

    Sokhansanj, Shahabaddine; Hess, J Richard

    2009-01-01

    Feedstock supply system encompasses numerous unit operations necessary to move lignocellulosic feedstock from the place where it is produced (in the field or on the stump) to the start of the conversion process (reactor throat) of the biorefinery. These unit operations, which include collection, storage, preprocessing, handling, and transportation, represent one of the largest technical and logistics challenges to the emerging lignocellulosic biorefining industry. This chapter briefly reviews the methods of estimating the quantities of biomass, followed by harvesting and collection processes based on current practices on handling wet and dry forage materials. Storage and queuing are used to deal with seasonal harvest times, variable yields, and delivery schedules. Preprocessing can be as simple as grinding and formatting the biomass for increased bulk density or improved conversion efficiency, or it can be as complex as improving feedstock quality through fractionation, tissue separation, drying, blending, and densification. Handling and transportation consists of using a variety of transport equipment (truck, train, ship) for moving the biomass from one point to another. The chapter also provides typical cost figures for harvest and processing of biomass.

  8. Prevalence of item level negative symptoms in first episode psychosis diagnoses.

    LENUS (Irish Health Repository)

    Lyne, John

    2012-03-01

    The relevance of negative symptoms across the diagnostic spectrum of the psychoses remains uncertain. The purpose of this study was to report on prevalence of item and subscale level negative symptoms across the first episode psychosis (FEP) diagnostic spectrum in an epidemiological sample, and to ascertain whether items and subscales were more prevalent in a schizophrenia spectrum diagnoses group compared to an \\'all other psychotic diagnoses\\' group. We measured negative symptoms in 330 patients presenting with FEP using the Scale for Assessment of Negative Symptoms (SANS), and ascertained diagnosis using the Structured Clinical Interview for DSM IV. Prevalence of SANS items and subscales were tabulated across all psychotic diagnoses, and logistic regression analysis determined which items and subscales were predictive of schizophrenia spectrum diagnoses. SANS items were most prevalent in schizophrenia spectrum conditions but frequently presented in other FEP diagnoses, particularly substance induced psychotic disorder and Major Depressive Disorder. Brief psychotic disorder and bipolar disorders had low levels of negative symptoms. SANS items and subscales which significantly predicted schizophrenia spectrum diagnoses, were also frequently present in some of the other psychotic diagnoses. Conclusions: SANS items have high prevalence in FEP, and while commonest in schizophrenia spectrum conditions are not restricted to this diagnostic subgroup.

  9. Outsourcing Logistics Activities: Evidence from Slovenia

    Directory of Open Access Journals (Sweden)

    Klemen Kavčič

    2016-12-01

    Full Text Available The purpose of this research is to investigate how logistics outsourcing performs activities that have been traditionally carried out within the outsourcer’s company. The study examines the characteristics of logistics and transport services, which are important in cooperation with service providers. Two groups were formed according to the average values of the characteristics of logistics activities. ‘Cost, quality and response’ are important for the first group, while ‘logistics, environment and the ability to adapt to client processes’ are important for the second group. The results of the survey carried out in Slovenian enterprises show that both groups are primarily interested in express freight and shipment services, the difference lying in the understanding of logistics, mutual trust and brand recognition. The findings will be useful both in business practice and for managers, providing them with a better understanding of the performance of logistics outsourcing.

  10. E-LOGISTICS – MULTIMODAL TRANSPORT MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Marcel LITRA

    2013-05-01

    Full Text Available The paper presents the role and the importance of logistics for products and services inorder to obtain the competitive advantage. After a short presentation of logistics evolution, we moveon to defining the logistics concept, respectively integrated logistics. The analysis of the logisticsactivities is based on the total cost concept and it has as a purpose the efficient and effectivemanagement of the physical flows of raw materials, materials and finite products, and of theinternational flows. The competitive advantage is ensured through the harmonization of the logisticsfunction with the other functions of the company and through the integration of the logistics chain ofall upstream and downstream organizations in order to ensure a high level of consumer service ateconomical costs under the farm of supply chain management. In the end we present the maintendencies in the evolution of logistics in the Romanian firms under the circumstances of the increaseof their international dimension.

  11. Reverse logistics for recycling: The customer service

    Directory of Open Access Journals (Sweden)

    Reis, E.

    2009-01-01

    Full Text Available Customer service is a central concern in the logistics practice and a study topic in the forward logistics research. This article investigates the elements of customer service and their importance in reverse logistics for recycling. Since consumer is the first intervenient in any reverse system that aims to recycle household residues, the provision of an adequate customer service gains an increased importance. Applying multivariate statistical methods (exploratory factor analysis, confirmatory factor analysis and discriminant analysis to the data from a sample of 267 Portuguese citizens, this study identifies the levels of customer service in this reverse logistics chain and evaluates their relative importance in achieving consumers’ participation. The study finds that, as in forward logistics, the customer service in reverse channels for recycling also has a hard and a soft level, being the former more important than the later. The results of this research suggest important guidelines to improve such a complex logistics service.

  12. Reversed item bias: an integrative model.

    Science.gov (United States)

    Weijters, Bert; Baumgartner, Hans; Schillewaert, Niels

    2013-09-01

    In the recent methodological literature, various models have been proposed to account for the phenomenon that reversed items (defined as items for which respondents' scores have to be recoded in order to make the direction of keying consistent across all items) tend to lead to problematic responses. In this article we propose an integrative conceptualization of three important sources of reversed item method bias (acquiescence, careless responding, and confirmation bias) and specify a multisample confirmatory factor analysis model with 2 method factors to empirically test the hypothesized mechanisms, using explicit measures of acquiescence and carelessness and experimentally manipulated versions of a questionnaire that varies 3 item arrangements and the keying direction of the first item measuring the focal construct. We explain the mechanisms, review prior attempts to model reversed item bias, present our new model, and apply it to responses to a 4-item self-esteem scale (N = 306) and the 6-item Revised Life Orientation Test (N = 595). Based on the literature review and the empirical results, we formulate recommendations on how to use reversed items in questionnaires.

  13. New Technology Applications for Military Logistics

    Science.gov (United States)

    2002-03-01

    This paper is a preliminary examination of the relationship between various new technologies and modern military logistics . A brief overview of...Canadian military logistics is given together with a list of important factors such as defence policy and geography that play a significant role in...number of leading-edge technologies are listed and their potential relationships with military logistics are highlighted. Finally, a short discussion of the opportunities and risks contained in these relationships is presented.

  14. Sustainment and Logistics in Better Buying Power

    Science.gov (United States)

    2015-07-01

    logistics successes of the last 14 years have shown that logistics is a significant U.S. competitive advantage . Main- taining that advantage will... competition and enhance affordability. Specific actions such as taking better advantage of commercial technology refresh cycles can apply to post...37 Defense AT&L: July–August 2015 Sustainment and Logistics in Better Buying Power David J. Berteau Berteau is Assistant Secretary of Defense

  15. Future Studies and Forecasting in Logistics

    OpenAIRE

    Heikkinen, Susanna

    2012-01-01

    This research study analyses the relation between strategy and forecasting. In more concrete terms, it analyses if current logistics research provides sufficient and valid data to be meaningfully implemented on strategy development. The relationship of strategy and forecasting is evaluated in case study of Nurminen Logistics Oyj. The main research question is, what is the competitive advantage in the future for logistics companies in Finland and what kind of future research would be usef...

  16. 24th Annual Logistics Conference and Exhibition

    Science.gov (United States)

    2008-03-13

    in Time Delivery" Business like era Conclusions 17 In war Logisticians determine who will win, Then Operators go forth and make it happen Erwin ... Rommel Questions? Joint Logistics Advocate and Integrator Synchronizing Global Defense Logistics LTG C.V. Christianson Director of Logistics (J-4) Joint...Partnership Security Stability UNITED STATES  AFRICA  COMMAND       The overall classification of this presentation is UNCLASSIFIED Brig Gen Rick Martin

  17. IMPORTANCE OF LOGISTICS OPERATORS IN INTERNATIONAL MARKET

    OpenAIRE

    KATARZYNA GRONDYS; RUZENA LOVASOVA; ANNA STELMASZCZYK; WIKTOR JANIK

    2014-01-01

    The aim of the article is to present role and importance of logistics operations in international arena. The article focuses on forms of outsourcing in logistics and their evolution over the years. The article discusses in detail the scope of logistics operators' activities on global scale over several years. Article also presents results of research, their analysis according to the sector of activities, their percentage share and financial benefits of using 3PL service providers. The progres...

  18. Reverse Logistics and Market-Driven Management

    OpenAIRE

    Gandolfo, Alessandro; Sbrana, Roberto

    2008-01-01

    The reverse logistics applies to the flow of products and materials in the opposite direction to direct logistics, from the market to the production sites or the specialised centres, where they are sent to be appropriately treated. The growing attention to reverse logistics is explained primarily by the need to comply with regulations on environmental protection, Given the intensified competition caused by rising costs of energy and raw materials, the truly market-driven companies cannot cons...

  19. Integrated Computer System of Management in Logistics

    Science.gov (United States)

    Chwesiuk, Krzysztof

    2011-06-01

    This paper aims at presenting a concept of an integrated computer system of management in logistics, particularly in supply and distribution chains. Consequently, the paper includes the basic idea of the concept of computer-based management in logistics and components of the system, such as CAM and CIM systems in production processes, and management systems for storage, materials flow, and for managing transport, forwarding and logistics companies. The platform which integrates computer-aided management systems is that of electronic data interchange.

  20. Transport Efficiency Through Logistics Development: Policy Study

    OpenAIRE

    Asian Development Bank

    2012-01-01

    Logistics includes material flow, information flow, and financial flow between the point of supply and the point of consumption, with transport serving as its core. With the rapidly evolving economy of the People’s Republic of China, there is a need for a modern transport and logistics system that is efficient, safe, sustainable, and meets customers’ requirements. This policy brief describes the current state of transport and logistics development in the PRC. It provides policy recommendation...

  1. Assessing the National Logistics System of Vietnam

    OpenAIRE

    Ruth Banomyong; Vinh V. Thai; Kum Fai Yuen

    2015-01-01

    The purpose of this research is to present and analyse the current situation regarding the capability of the national logistics system in Vietnam. A national assessment framework for macro-logistics is utilised in combination with semi-structured interviews of key Vietnamese stakeholders to reflect on the current situation in the country. There are still numerous shortcomings in the Vietnamese logistics system. These shortcomings are not purely infrastructure based but also from a regulatory ...

  2. Business Relations in Reverse Logistics Outsourcing

    OpenAIRE

    Janusz Grabara; Sebastian Kot

    2010-01-01

    Nowadays cost reduction is a fundamental strategy used in companies during fighting for survival, keeping or increase in sales levels and profits. More and more often observed tendency to concentrate commercial and production companies leads to rise of demand for outsourcing in a reverse logistics chain. In the paper Authors present concept of outsourcing in logistics processes, advantages of outsourcing in reverse logistics and types of relations between outsourcing partners as well as areas...

  3. Flexible logistic concepts for assembly systems

    Directory of Open Access Journals (Sweden)

    2010-06-01

    Full Text Available Logistics is a crucial issue for small and medium sized enterprises (SME. This paper deals with logistical concepts for assembly systems. The IPH is currently conducting a project with the aim of developing a method to combine allocation and delivery concepts for assembly systems to increase the logistical efficiency of SME. Via this method SME are able to adapt quickly to changing market environments.

  4. A New Advanced Logistics Supply Chain for Food Management Based on Green Logistics Theory

    Directory of Open Access Journals (Sweden)

    Lanqing Liu

    2013-10-01

    Full Text Available The study aims to investigate the advanced logistics supply chain for food management using green logistics. To protect the food logistics environment and prevent the environmental pollution, it is crucial to establish powerful modern supply chains to support the food management in transportation. The construction speed of the food companies is very fast; however, the food supply lags behind the food companies. As a result, the environmental pollution caused in the food logistics becomes severe. To improve this situation, a new logistics supply chain for food management using the environmental logistics theory is proposed in this study. The design and analysis of the proposed food supply chain system has been introduced. By the use of advanced environmental logistics theory, the food supply can be operated in an effective and green manner. Hence, the proposed new logistics supply chain can reduce the environmental pollution of the food logistics and improve the food market environment.

  5. Management of Logistics Activities and Costing Approaches

    Directory of Open Access Journals (Sweden)

    İlker KIYMETLİ ŞEN

    2014-06-01

    Full Text Available In recent years, enterprises are required to reconsider the management of logistics activities as a result of developments such as increasing competition, rapid technological development, and the shortening of product life cycles. As a result of globalization, costs of logistics activities have also increased depending on changes in the quality and quantity of logistics activities. According to research on logistics activities, the physical distribution costs of enterprises may reach up to 30% of sales. For this reason, the management of logistics operations and control of costs caused by these activities is a necessity. The increase in costs negatively impact on the financial performance of enterprises, cash flows, profitability and so value of the shares. The aim of this study was to describe the structure of logistics costs and logistics activities to explain the methods used in costing. For this purpose, many studies in the literature were investigated. The aim of this study was to describe the structure of logistics costs and logistics activities to explain the methods used in costing. For this purpose, many studies in the literature were investigated.

  6. Outsourcing of Transport and Logistics Services

    Directory of Open Access Journals (Sweden)

    Anton Ogorelc

    2007-11-01

    Full Text Available The author presents the results of the research in five parts,which are interconnected. After the introduction, in part two,entitled A Framework for Logistics Outsourcing Decisions,theoretical characteristics of outsourcing are presented. Partthree, Core Competences and Outsourcing, describes the logisticscompetences. Part 4, Transp011 and Logistics Outsourcingin Europe, discusses the trends in logistics development andoutsourcing. The paper will assist managers responsible for thedevelopment of logistics strategies. The paper offers a uniquebuyer-supplier pwtnership framework by proposing that the logisticsoutsourcing will increase the competitive advantage ofmanufacturing firms.

  7. Analysis of Jingdong Mall Logistics Distribution Model

    Science.gov (United States)

    Shao, Kang; Cheng, Feng

    In recent years, the development of electronic commerce in our country to speed up the pace. The role of logistics has been highlighted, more and more electronic commerce enterprise are beginning to realize the importance of logistics in the success or failure of the enterprise. In this paper, the author take Jingdong Mall for example, performing a SWOT analysis of their current situation of self-built logistics system, find out the problems existing in the current Jingdong Mall logistics distribution and give appropriate recommendations.

  8. Logistic Regression for Evolving Data Streams Classification

    Institute of Scientific and Technical Information of China (English)

    YIN Zhi-wu; HUANG Shang-teng; XUE Gui-rong

    2007-01-01

    Logistic regression is a fast classifier and can achieve higher accuracy on small training data. Moreover,it can work on both discrete and continuous attributes with nonlinear patterns. Based on these properties of logistic regression, this paper proposed an algorithm, called evolutionary logistical regression classifier (ELRClass), to solve the classification of evolving data streams. This algorithm applies logistic regression repeatedly to a sliding window of samples in order to update the existing classifier, to keep this classifier if its performance is deteriorated by the reason of bursting noise, or to construct a new classifier if a major concept drift is detected. The intensive experimental results demonstrate the effectiveness of this algorithm.

  9. LOGISTICS AS A PART OF INNOVATION PROCESS

    Directory of Open Access Journals (Sweden)

    Erika Loučanová

    2016-03-01

    Full Text Available The paper deals with the importance of logistics in innovation process. The issue is focused on management of different logistic processes building on the innovation and on innovation process. However, logistics is an essential part of this process. The results describe logistics chain within innovation process for the satisfaction of customers´ demand and fulfilment of customers’ requests on the innovation. This approach involves “7S of logistics” which means: “create proper innovation, in the proper quality, for the right place and in the right time, as well as, with the proper price and package”.

  10. CITY LOGISTICS – STATUS AND TRENDS

    Directory of Open Access Journals (Sweden)

    Snežana Tadić

    2015-09-01

    Full Text Available City logistics aims to increase the efficiency and mitigate the negative effects of logistics processes and activities, and at the same time support the sustainable development of the urban areas. Major European and national research projects, undertaken from the end of the last century onwards, indicate that the state of the urban area logistics is quite critical. The situation requires a comprehensive analysis and active participation of the authorities and companies in order to solve the growing problems and define the sustainable solutions which would encourage the economic development and improve the living conditions in the city. In order to make logistics activities less routine, and thereby more efficient, many initiatives have been launched, especially in the terms of environmental impact and service quality. However, the changes are slow and environmental trends are setting new challenges. The main problem is the lack of planning activities and comprehensive and long term policy of city logistics. Decisions of city planners are often inadequate, without the analysis of existing situation and interaction of city logistics and complex socio-economic system of the city and its surrounding, without research and studies of different measures and impacts on the overall city logistics system. This article presented the current situation and trends in the implementation of logistics chains within the urban areas in order to highlight the complexity of solving the problems of a complex city logistics system.

  11. ISS ECLSS: 3 Years of Logistics for Maintenance

    Science.gov (United States)

    Shkedi, Brienne; Thompson, Dean

    2004-01-01

    The International Space Station (ISS) Environmental Control and Life Support System (ECLSS) is designed to be maintainable. During the 3 years since the ISS US Lab became operational, there have been numerous ECLSS Orbital Replacement Units (ORUs) launched and returned to Maintain the ECLSS operation in the US segments. The maintenance logistics have provided tools for maintenance, replaced limited life ORUs and failed ORUs, upgraded ECLSS hardware to improve reliability and placed critical spares onboard prior to need. In most cases, the removed ORUs have been returned for either failure analysis and repair or refurbishment. This paper describes the ECLSS manifesting history and maintenance events and quantifies the numbers of ECLSS items, weights, and volumes.

  12. The reliability assessment of the electromagnetic valve of high-speed electric multiple units braking system based on two-parameter exponential distribution

    Directory of Open Access Journals (Sweden)

    Jianwei Yang

    2016-06-01

    Full Text Available In order to solve the reliability assessment of braking system component of high-speed electric multiple units, this article, based on two-parameter exponential distribution, provides the maximum likelihood estimation and Bayes estimation under a type-I life test. First of all, we evaluate the failure probability value according to the classical estimation method and then obtain the maximum likelihood estimation of parameters of two-parameter exponential distribution by performing and using the modified likelihood function. On the other hand, based on Bayesian theory, this article also selects the beta and gamma distributions as the prior distribution, combines with the modified maximum likelihood function, and innovatively applies a Markov chain Monte Carlo algorithm to parameters assessment based on Bayes estimation method for two-parameter exponential distribution, so that two reliability mathematical models of the electromagnetic valve are obtained. Finally, through type-I life test, the failure rates according to maximum likelihood estimation and Bayes estimation method based on Markov chain Monte Carlo algorithm are, respectively, 2.650 × 10−5 and 3.037 × 10−5. Compared with the failure rate of a electromagnetic valve 3.005 × 10−5, it proves that the Bayes method can use a Markov chain Monte Carlo algorithm to estimate reliability for two-parameter exponential distribution and Bayes estimation is more closer to the value of electromagnetic valve. So, by fully integrating multi-source, Bayes estimation method can preferably modify and precisely estimate the parameters, which can provide a certain theoretical basis for the safety operation of high-speed electric multiple units.

  13. Examining item difficulty and response time on perceptual ability test items.

    Science.gov (United States)

    Yang, Chien-Lin; O'Neill, Thomas R; Kramer, Gene A

    2002-01-01

    This study examined item calibration stability in relation to response time and the levels of item difficulty between different response time groups on a sample of 389 examinees responding to six different subtest items of the Perceptual Ability Test (PAT). The results indicated that no Differential Item Functioning (DIF) was found and a significant correlation coefficient of item difficulty was formed between slow and fast responders. Three distinct levels of difficulty emerged among the six subtests across groups. Slow responders spent significantly more time than fast responders on the four most difficult subtests. A positive significant relationship was found between item difficulty and response time across groups on the overall perceptual ability test items. Overall, this study found that: 1) the same underlying construct is being measured across groups, 2) the PAT scores were equally useful across groups, 3) different sources of item difficulty may exist among the six subtests, and 4) more difficult test items may require more time to answer.

  14. From concepts to lexical items.

    Science.gov (United States)

    Bierwisch, M; Schreuder, R

    1992-03-01

    In this paper we address the question how in language production conceptual structures are mapped onto lexical items. First we describe the lexical system in a fairly abstract way. Such a system consists of, among other things, a fixed set of basic lexical entries characterized by four groups of information: phonetic form, grammatical features, argument structure, and semantic form. A crucial assumption of the paper is that the meaning in a lexical entry has a complex internal structure composed of more primitive elements (decomposition). Some aspects of argument structure and semantic form and their interaction are discussed with respect to the issue of synonymy. We propose two different mappings involved in lexical access. One maps conceptual structures to semantic forms, and the other maps semantic forms to conceptual structures. Both mappings are context dependent and are many-to-many mappings. We present an elaboration of Levelt's (1989) model in which these processes interact with the grammatical encoder and the mental lexicon. Then we address the consequences of decomposition for processing models, especially the nature of the input of lexical access and the time course. Processing models that use the activation metaphor may have difficulties accounting for certain phenomena where a certain lemma triggers not one, but two or more word forms that have to be produced with other word forms in between.

  15. A common language for logistics services interoperability

    NARCIS (Netherlands)

    Gonzalez-Rodriguez, M.; Vennesland, A.; Dalmolen, S.

    2015-01-01

    Transport logistics is immersed in a world-wide changing process. The fluctuating market necessities, the distribution of production facilities, the influence of the emerging economies and the environmental compromise force transport logistics services to be as dynamic as possible, answering to real

  16. Standards for Standardized Logistic Regression Coefficients

    Science.gov (United States)

    Menard, Scott

    2011-01-01

    Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

  17. A Proposed Logistics Career Development Model.

    Science.gov (United States)

    1986-09-01

    Both Professor Peppers and Professor Demidovich called for pioneers in logistics dynam- ics. They stated that it was part of every logistics manag- er’s...Force Institute of Technology (AU), Wright-Patterson AFB OH, August 1967 (AD-A824 956). 12. Demidovich , John W. and Jerome G. Peppers, Jr. "The

  18. Sustainability assessment of food chain logistics

    NARCIS (Netherlands)

    Bloemhof, J.M.; Vorst, van der J.G.A.J.; Bastl, M.; Allaoui, H.

    2015-01-01

    Food chain logistics plays an important role in the sustainability performance of the food sector. Therefore, project SCALE (Step Change in Agri-food Logistics Ecosystems) started as a collaborative international project, aiming for tools and frameworks for the food sector to make a step change in o

  19. Military logistics and its application in missions

    OpenAIRE

    2014-01-01

    This thesis deals with the problems of logistics and its application in the military. There are mentioned various areas of using logistics in the military. It also describes the implementation of support for foreign missions, especially in the area of supply. Because of the difficultness of transport tasks it is used linear programming for the solution.

  20. Logistics outsourcing by manufacturers in South Africa

    Directory of Open Access Journals (Sweden)

    Beverley Waugh

    2011-11-01

    Full Text Available As organisations find themselves in an increasingly dynamic and competitive world they are seeking new strategies to ensure their competitive advantage and profitability. Logistics presents an area in which these organisations can improve customer service and reduce costs, and strategies in support thereof such as the outsourcing of logistics activities, should be considered. However, it is critical that logistics outsourcing is done diligently to avoid potential problems for the organisation and to achieve the best possible benefits. In South Africa little research has been done regarding current outsourcing practices of local manufacturers. In this article literature on international logistics outsourcing as well as research on some of the logistics outsourcing practices of South African manufacturers is discussed. The findings of a questionnaire survey of South African manufacturers provided information on their logistics outsourcing practices and problems. Prominent issues seem to include inadequate managerial involvement in the logistics outsourcing process, as well as insufficient time spent on many of the important aspects of the outsourcing agreement, the transitioning of resources and ongoing management of the outsourced relationship. It is concluded that a thorough outsourcing process should be followed in order to achieve the benefits of logistics outsourcing.