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ABC analysis is used to sort inventory into categories which determine how much attention they will be given. But it is of wider management application and can be extended to cope with more than one classification criterion.

With tongues planted firmly in cheeks and with apologies to Murphy, we offer some forecasting laws for management.

A performance comparison study of six time-series change detection procedures via forecast-monitoring simulation is presented. Four of the procedures are due to Brown [1], Page [2], Box and Tiao [3] and Gardner [4]. The other two sequential detection schemes are developed in this paper; the first is based on Bagshaw and Johnson [5], while the second employs a moving-block estimator of innovations autocovariance. Eighty synthetic time series were generated, using an autoregressive model, an integrated-moving average model and a time-regression model having step changes in the parameters. The statistics being employed are based upon cumulative sum (cusum), squared cusum and discounted cusum of the innovations from the corresponding forecasting models. Results of this study indicate that the procedures which employ squared cusum and nondiscounted cusum of innovations yield smaller rates of false detection. The two best change-detection statistics of this study appear to possess good potential for industrial and business forecast monitoring applications.

The selection of forecasting methods is a complicated issue. The situation is created by the need to identify the best method for a time series. Criteria for selection must be defined. If the sole criterion is accuracy, then a comparison of two forecasting methods can be made by testing them ex post while utilizing the time series. Care should be exercised in the selection of the accuracy metric. A statistical test should be made to determine if the results are significantly different. The test recommended is the Wilcoxson test since it is less restrictive to the nature of the error and less susceptible to outliers.

This paper addresses the importance of goal setting in the operations function. The importance of goal setting and its possible role in the implementation and operation of production systems is considered with particular emphasis on Material Requirements Planning (MRP). It has been argued that an operative goal setting process can improve employees' performance in any area of the organisation. Likewise, companies with a high‐level MRP system are expected to show high performance levels. This paper offers empirical support for these claims and further argues that the combination and interaction of the two processes results in synergistic effects. To support these arguments the paper draws on both theoretical studies and the results of a small regional survey.

This article presents the results of applying multicriteria ABC analysis to maintenance inventories. A large service organization and a consumer goods manufacturer participated in the study. The managers in both organizations used cost and noncost criteria for developing the ABC categories for inventory management. The study shows that managers can develop noncost criteria and classify the inventory items in ways that combine the criteria types. Specific policies were defined for managing the items in the industrial firm. Once the benefits of the methodology were demonstrated, a year-long program for implementing the system was developed. The project is estimated to cost less than 10 to 15% of the available storeroom clerk manhours and provide substantially greater benefits.

Accuracy measurement in forecasting is always a subject of debate because of its importance. An adequate metric is necessary to properly select a forecasting method for a specific application. Competitions to determine the best method have helped the practitioner. The criteria for selection have not received as much attention. Of the two kinds of measurement statistics—relative and absolute—the former may present problems for the user if zeros or near zero values appear. This is more a practitioner problem because artificially generated time series do not usually have zeros. The relative and absolute measures are discussed and a solution for the existence of zeros in the data is given. If symmetry of the errors is a problem solutions are discussed. Managers will select the metric depending on the application and their management style. Once the metric has been selected the decision as to which forecasting method to select in a given situation becomes a less difficult problem.

The paper reports results of an experiment conducted to evaluate subjective versus objective combination of forecasts. The subjects were undergraduate students at Texas A&M. The students forecasted two different types of time series. The results found show that the subjective combination of forecasts improves their accuracy as compared with individual efforts. Four ex-ante weighting methods were also used to combine the forecasts. They all improve the accuracy of the forecasts. The best results, though, were from the subjective combination of forecasts.

The utilization of an accuracy measure such as Percentage Better can be made more meaningful if it is supplemented with a statistical test of the significance of the results. For the Percentage Better, the Sign Test can be useful. In this paper, some of the results of the Makridakis competition are re-analyzed to illustrate this point. The results make for a clearer interpretation and easier use to identify the best forecasting method in a pairwise fashion

Prioritising items for management attention has been advocated in operations management for a long time, normally using ABC analysis (inventory control). This focuses attention on the “A” category items to maximise managerial effectiveness. Empirical evidence shows that this is a reasonable rule for allocating scarce resource‐management time but presents difficulties when the manager has to take more than one important dimension of a situation into account. A joint criteria matrix is put forward within the ABC framework and an industrial application given. The joint criteria matrix has practical utility provided ranking on some scale of measurement is realistic. The appropriate number of categories must be defined by the user. Combining criteria will probably require different analytical approaches, e.g. goal programming or heuristic approaches. Utilisation of the matrix by managers can provide an explicit method for taking a range of criteria into account in the development of inventory policies.

l. Suelos-Física. Valores estimativos de la torrencialidad obtenidos por comparación de distintos métodos de valoración aplicados en la provincia de Valencia. Por V. Bordas Valls, V. Pons Marti y J. Sánchez Díaz.-- Química Metodología y valores estimados para definir el riesgo de degradación química de los suelos en la provincia de Valencia. Por V. Bordas y J. Sánchez.- Origen de materiales alofánicos en suelos volcánicos del campo de Calatrava (Ciudad Real). Por J. L. Martín de Vidales, J. Guijarro, M. A. Hoyos y J. Casas.-- Influencia de un ciclo agroforestal sobre la actividad ureásica en suelos cálcicos. Por S. González Carcedo, M. Pérez Mateos y E. Barriuso Benito.-- Génesis, Clasificación y Cartografía Suelos sobre sedimentos terciarios afectados por la terraza alta del Guadiana en Badajoz (España). Por A. García Navarro y L. Fernández Pozo.-- Génesis y clasificación de los suelos desarrollados sobre las anfibolitas de "Santiago - Ponte Ulla". Por B. M. Silva Hermo, E. García-Rodeja Gayoso, C. García Paz y F. Macías Vázquez.-- Factores ecológicos (Geología, vegetación y clima) de la comarca La Plana de Requena - Utiel (Valencia): I. Relaciones suelo-Material de origen. Por R. Boluda Hernández, V. Andréu Pérez, M. Moraleda Esteve y J. Sánchez Diaz.-- Factores ecológicos (Geología, vegetación y clima) de la comarca La Plana de Requena - Utiel (Valencia): II. Vegetación y clima. Por R. Boluda Hernández, V. Andréu Pérez, M. Moraleda Esteve y J. Sánchez Díaz. II. Biología Vegetal-Fisiología Efectos del ácido 2,4-Diclorofenoxiacético sobre el crecimiento, diferenciación y morfogénesis de un cultivo de callo de erysimum scoparium de un año de edad. Por J. F. Pérez Francés, F. Valdés, R. Martín y B. R. Rodríguez.-- Efecto del GA3 sobre el desarrollo del ápice del tallo de la cebada (Hordeum _ distichon L. cv. "Pallas"). Por M. Díaz-Miguel.-- Effect of elemental sulphur application to Brassica juncea coss. By L. L. Somani, l. J. Gulati, K. K. Vyas and P. C. Kanthalia.-- Efecto sobre la germinación de semillas del extracto hidrosoluble de hojas de especies mediterráneas: introducida: Eucalyptus globulus Labill y autóctonas: Quercus suber L., Quercus ilex L., Pinus pinea L., Cistus ladanifer L. y Halimium halimifolium Wk. Por M. T. Dominguez, E. G. Esparcia y F. Penalva.-- Agrobiologfa Calibration of critica! limits of various soil potassium parameters for wheat crop in Torri - psamment soils of western ghat (India). By S. P. Mazumdar and S. N. Sax Ena.--Factores ecológicos que determinan la distribución del olivo en la España peninsular. Por L. Ramirez-Pérez y B. Peco.-- III. Comunicaciones cortas. Relación suelo - agua en las formaciones de Raña del centro - oeste de España. Por R. Espejo Serrano, y J. Pérez Arias .-- Consideraciones sobre el estado actual y perspectivas en ecología del suelo. Por A. García Álvarez y J. J. lbáñez.-- IV. Trabajo recapitulativo. Origen, situación y características de las variedades de albaricoquero de Murcia. Por L. Eggea, T. Berenguer, J. Egea y J. E. García. Notas Peer reviewed 2019-08.- CopyBook.- Libnova.- Biblioteca ICA

Suelos. Interacción del dimetilsulfóxido con montmorillonitas, por G. Dios Cancela y S. González García.-- Complejos de adsorción de la montmorillonita. I., por S. González García, G. Dios Cancela y A. García Fernández.-- Complejos de adsorción de la montmorillonita. Il., por G. Dios Cancela, S. González García y A. García Fernández.-- Complejos de adsorción de la montmorillonita. I., por S. González García, G. Dios Cancela y A. García Fernández.-- Complejos de adsorción de la montmorillonita. II por S. Dios Cancela, S. González y A. García Fernández.-- Estudio de las características del sistema edáfico de Sierra Nevada, por E. Barahona, R. Delgado Calvo-Flores y J. Linares.-- El relieve como factor formador de los suelos de Sierra Nevada, por R. Delgado CalvoFlores, E. Barahona y J. Linares.-- Los factores de edafogénesis en suelos de margas, por L J. Alias Pérez. G. Sánchez García y María T. Fernández Tapia.-- Utilización del evaporamiento en la programación del riego, por A. León, F. del Amor y A. Torrecillas.-Modelo experimental de alteración de feldespatos. Ill., por Hoyos de Castro, A., Hernando Massanet, M. I., Hernando Costa, J. y Pisonero Ruiz, L.-- Características petroquímicas y micromorfológicas de Xerochrepts, por P. Arévalo, J. Gallardo y J. Benayas.-- Los suelos de la Sierra del Barbanza: 5) Las formaciones "campa", por Torras Troncoso, M." L., .Gil Sotres, F., Diaz-Fierros Viqueira, F.-- Suelos empardecidos. l. Factores formadores, por Hoyos de Castro, A., Palomar G. Villamil, M. L., Hernando Costa, J. y Egido Rodríguez, J. A. Suelos empardecidos. II. Estudio de la materia orgánica, por Hoyos de Castro, A., Palomar G. Vil/ami/, M. L., Hernando Costa, J. y Egido Rodríguez, J. A.-- Suelos empardecidos. III. Estudio químico y físico-químico, por Hoyos de Castro, A., Palomar G. Villamil, M. L., Hernando Costa, J. y Egido Rodríguez, J. A. -- Los factores ecológicos en la génesis y evolución de suelos, por A. Hoyos, J. G. Parra, C. G. Huecos y A. L. Lafuente.-- Determinación de microtrazas de actividad ureásica en suelo, por González Carcedo, S. y Barriuso Benito, E.-- Efectos erosivos de los incendios forestales en suelos, por F. Diaz-Fierros, V., F. Gil Sotres, A. Cabaneiro, T. Carballas, M. C. Leiros de la Peña y M. C. Villar Celorio 627 Materia orgánica de tierras pardas ácidas, por J. Bech, A. Hereter y R. Vallejo.-- Fertilidad de los Suelos. Fertilización potásica en suelos pobres sobre ryegrass y trifolium, por J. A. Diez.-- Estudio electroforético del punto isoeléctrico de óxidos de hierros, por Rafael Martinez Gosca, Juan Cornejo y Pablo de Arambarri.--Necesidad en cal de los suelos ácidos de Tenerife, por I. Trujillo Jacinto del Castillo, A. Borges Pérez, F. Gutiérrez Jerez y C. Curbelo Mújica.—Nutrición y Fisiología Vegetal. Efectos de la fertilización con N, P y K sobre los azúcares en hojas de vid, por C. Mozuelos, R . Romero, V. Valpuesta, R. Sarmiento y L. Catalina.-- Actividad biológica de algunos inhibidores naturales, por Durán, J. M. y Langreo, M.-- Redistribución de nutrientes en limonero verna, por A. Cerdá, M. Caro y F. Santa Cruz.-- Evoluciones de fósforo de distintas fracciones en la hoja citrus Iimonum, por María Parra y T. Parra.-- Distribución de nutrientes en la planta de tomate, por M." P. Sánchez Conde.-- Efectos de la luz, oscuridad y fotoperiodo sobre la germinación, por J. F. Pérez Francés, M. Niebla y A. C. Blesa.—Notas, 2019-08.- CopyBook.- Libnova.- Biblioteca ICA