Techniques for improving the performance of frequency-hopped multiple-access communication systems

Imperial Users onl

Diseño y desarrollo de un modelo y planificación óptima para la responsabilidad de la cadena de suministro con el medio ambiente

The responsible management of product return flows in production and inventory environments is a rapidly increasing requirement for companies. This can be attributed to economic, environmental and/or regulatory motivations. Mathematical modeling of such systems has assisted decision-making processes and provided a better understanding of the behavior of such production and inventory environments. This paper reviews the literature on the modeling of reverse logistics inventory systems based on the economic order/production quantity (EOQ/EPQ) and the joint economic lot size (JELS) settings to systematically analyze the mathematics involved in capturing the main characteristics of related processes. The literature is surveyed and classified according to the specific issues faced and modeling assumptions. Special attention is given to environmental issues. There are indications of the need for reverse logistics models' mathematics to follow current trends in ‘greening’ inventory and supply-chain models. The modeling of waste disposal, greenhouse-gas emissions, and energy consumption during production is considered as the most pressing priority for the future of reverse logistics models. An illustrative example for modeling reverse logistics inventory models with environmental implications is presented.La gestión responsable de los flujos de retorno de productos en entornos de producción e inventario es un requisito cada vez mayor para las empresas. Esto puede atribuirse a motivaciones económicas, ambientales y / o regulatorias. El modelado matemático de tales sistemas ha ayudado a los procesos de toma de decisiones y ha proporcionado una mejor comprensión del comportamiento de dichos entornos de producción e inventario. Este artículo revisa la literatura sobre el modelado de sistemas de inventario de logística inversa que se basan en la orden económica / cantidad de producción (EOQ / EPQ) y la configuración del tamaño de lote económico conjunto (JELS) para analizar sistemáticamente las matemáticas involucradas en la captura de las principales características de los procesos relacionados. La literatura se examina y clasifica de acuerdo con los problemas específicos que se enfrentan y los supuestos del modelo. Se presta especial atención a las cuestiones ambientales. Hay indicios de la necesidad de que las matemáticas de los modelos de logística inversa sigan las tendencias actuales en los modelos de cadena de suministro y inventario "ecológicos". La modelización de la eliminación de residuos, las emisiones de gases de efecto invernadero y el consumo de energía durante la producción se considera la prioridad más urgente para el futuro de los modelos de logística inversa. Se presenta un ejemplo ilustrativo para modelar modelos de inventario de logística inversa con implicaciones ambientales

Diseño y desarrollo de un modelo y planificación óptima para la responsabilidad de la cadena de suministro con el medio ambiente

La gestión responsable de los flujos de retorno de productos en entornos de producción e inventario es un requisito cada vez mayor para las empresas. Esto puede atribuirse a motivaciones económicas, ambientales y / o regulatorias. El modelado matemático detales sistemas ha ayudado a los procesos de toma de decisiones y ha proporcionado una mejor comprensión del comportamiento de dichos entornos de producción e inventario. Este artículo revisa la literatura sobre el modelado de sistemas de inventario de logística inversa que se basan en la orden económica / cantidad de producción (EOQ / EPQ) y la configuración del tamaño de lote económico conjunto (JELS) para analizar sistemáticamente las matemáticas involucradas en la captura de las principales característicasde los procesos relacionados. La literatura se examina y clasifica de acuerdo con los problemas específicos que se enfrentan y los supuestos del modelo. Se presta especial atención a las cuestiones ambientales. Hay indicios de la necesidad de que las matemáticas de los modelos de logística inversa sigan las tendencias actuales en los modelos de cadena de suministro y inventario "ecológicos". La modelización de la eliminación de residuos, las emisiones de gases de efecto invernadero y el consumo de energía durante la producción se considera la prioridad más urgente para el futuro de los modelos de logística inversa. Se presenta un ejemplo ilustrativo para modelar modelos de inventario de logística inversa con implicaciones ambientale

Diseño y desarrollo del modelo óptimo de asignación y cronograma de remolques en el sistema de cadena de suministro con consideración de cross dock con planificación estocástica

Todays, transportation, and logistics engineering processes are among the important issues of organizations in the competitive market. Considering the logistical structure of the logistics engineering and the more attention paid to the logistical tools and, in particular, such as the use of these tools, such as containers (pallets, containers, etc.), transportation equipment (trailer, forklift trucks, etc.), and The art of building the supply and distribution network concerning the main warehouses, cross-dock, and temporary storage, is one of the most critical and contemplative cases. In fact, all these tools work together to maximize system efficiency in the field of logistics concerning the leading impact indicators, including the time of shipment (loading, disloading, the allocation of trailers, etc.). This paper's main goal is to present and develop a mathematical model of trailer schedule planning in possible conditions in the cross-dock. In fact, the main function of this mathematical model is to minimize the total time of the logistics process from the stage of emptying the pallets from the materials producers in the cross docks and assigning the trailer to the door, and finally reloading the pallets to be distributed to the production sites. To solve this model and to analyze the outputs, mixed integer programming was used by GAMS software.Hoy en día, los procesos de ingeniería de transporte y logística se encuentran entre los temas importantes de las organizaciones en el mercado competitivo. Teniendo en cuenta la estructura logística de la ingeniería logística y la mayor atención prestada a las herramientas logísticas y, en particular, como el uso de estas herramientas, como contenedores (pallets, contenedores, etc.), equipos de transporte (remolque, carretillas elevadoras, etc.), y El arte de construir la red de suministro y distribución con respecto a los almacenes principales, cross dock y almacenamiento temporal, es uno de los casos más importantes y contemplativos. De hecho, todas estas herramientas trabajan juntas para maximizar la eficiencia del sistema en el campo de la logística con respecto a los principales indicadores de impacto, incluido el tiempo de envío (carga, descarga, asignación de remolques, etc.). El objetivo principal de este artículo es presentar y desarrollar un modelo matemático de planificación de horarios de remolques en las posibles condiciones en el muelle de cruce. De hecho, la función principal de este modelo matemático es minimizar el tiempo total del proceso logístico desde la etapa de vaciado de los pallets de los productores de materiales en los cross docks y la asignación del remolque a la puerta y finalmente la recarga de los pallets a distribuir. a los sitios de producción. Para resolver este modelo y analizar las salidas, el software GAMS utilizó la programación de enteros mixtos

Novel method for determination of trace amounts of citalopram in tablets by fast fourier continuous cyclic voltammetry at au microelectrode in flowing solutions

In this work, fast Fourier transform continuous cyclic voltammetric technique for the monitoring of ultra trace amounts of citalopram in a flow-injection system has been presented. The potential waveform, consisting of the potential steps for cleaning, stripping and potential ramp, was continuously applied on an Au disk microelectrode (with a 12.5 µm in radius). The proposed detection method has some advantages, the greatest of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The method was linear over the concentration range of 7 - 116 pg mL-1 (r = 0.9960) with a limit of detection and quantitation 2.3 and 7 pg mL-1, respectively. The method has the requisite accuracy, sensitivity, precision and selectivity to assay citalopram in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the citalopram were considered. The proposed method was applied to the determination of citalopram in a pharmaceutical preparation

Assessment of attention bias in the cognitive processing of neutral and emotional words Using semantic Strop test

Objective: This aim of this study was to assessment of attention bias in the cognitive processing of neutral and emotional words, using Stroop's semantic test on students. Method: 50 students from Tabriz University were selected randomly and in addition to the demographic information, they responded to the Stroop's semantic test. Data analysis was done using descriptive statistics, independent groups T-test and paired groups T-test. Results: The mean percentages of correct responses in the sample (boys and girls) in emotional words were lower than neutral words. The mean percentage of incorrect responses in the sample in neutral and emotional words was not significant. There were significant differences in neutral and emotional words between the mean percentages of without respondent in the sample in 0/001. There were significant differences in mean percentages of responses in the sample between the neutral and emotional words in 0/005. On the one hand, there were not significant differences in mean percentages of correct responses in boys in neutral and emotional words but for the girls; there were significant differences in0/005. For both sex, there were significant differences in mean response time between neutral and emotional words in 0/001

Comparison of diagnosis of VUR nephropathy by urinary level of ceruloplasmin with DMSA-Scan in children

Background: Children with vesicoureteral reflux (VUR) are at risk of recurrent pyelonephritis, kidney scars, hypertension, and renal failure. Currently, VUR complications can be diagnosed by different imaging methods such as sonography, intravenous pyelography and dimercaptosuccinic acid (DMSA) scan, having certain limitations. Urinary level of ceruloplasmin (Cp) might be an effective non-radiological method. The aim of this study was to compare the urinary level of Cp with DMSA scan in the diagnosis of VUR complications. Methods: The present cross-sectional study was conducted in Pediatric Research Center of Qom University of Medical Sciences and Health Services, Iran. Subjects consisted of 61 children with VUR, diagnosed by voiding cystoureterography (VCUG) and undergone either DMSA scan or urine Cp measurement. VUR stages and complications of the cases were evaluated using serum and urinary renal parameters. Data were analyzed using SPSS 22. Results: Among them, 80.3% were girls with a mean age of 7.2±3.8 years. Mean Cp urine level was statistically different between VUR sides in DMSA scan (unilateral: 269.56 vs. bilateral: 450.42 µg/dL) (P=0.034, r =0.273), but was not statistically different among various VUR degrees (P=0.102, r=0.211), different ages and genders (P>0.05). Conclusions: Urinary level of Cp was not statistically different among VUR degrees, but was higher in bilateral VUR cases, indicating Cp can be used as a safe, non-invasive, and cheap measurement tool for screening test. Further studies are required to confirm Cp as an effective method

Susceptibility of Males and Females of Cucumber Fruit Fly, Dacus ciliatus, to Various Insecticides in the Laboratory Conditions

Abstract The cucumber fly, Dacus ciliatus Loew., is a destructive pest of cucurbit crops in some regions of Iran. Susceptibility of adults of D. ciliatus to various insecticides (deltamethrin, dimethoate, trichlorofon, spinosad, acetamiprid, and malathion) was investigated. The insecticide toxicity was tested through contact method in three stages (males only, females only, and a mixture of males and females). The results showed that the used insecticides excellently affected on males and females of D. ciliatus through contact toxicity. Also, their effect on the mixture of males and females was acceptable. In addition, dimethoate and deltamethrin were better than the others. The LC 50 values of these two were less than 1 mg L -1 . Also, except for acetamiprid, LC 50 vales of all other insecticides on males and females were close