1,728 research outputs found

    Models and Algorithms for Inbound and Outbound Truck to Door Scheduling

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    Cross-docking is a logistic strategy that facilitates rapid movement of consolidated products between suppliers and retailers within a supply chain. It is also a warehousing strategy that aims at reducing or eliminating storage and order picking, two of which are known to be major costly operations of any typical warehouse. This strategy has been used in the retailing, manufacturing, and automotive industries. In a cross-dock, goods are unloaded from incoming trucks, consolidated according to their destinations, and then, loaded into outgoing trucks with little or no storage in between. In this thesis, we address an integrated cross-dock door assignment and truck scheduling problem in which the assignment and sequencing of incoming trucks to strip doors and outgoing trucks to stack doors is optimized to minimize the total time to process all trucks. We present a mixed integer programming formulation to model this problem and some valid inequalities to strengthen the formulation. We also present two metaheuristics to obtain high quality solutions in reasonable CPU times. These algorithms use a mix of composite dispatching rules, constructive heuristics, local search heuristics which are embedded into a greedy randomized adaptive search procedure (GRASP) and an iterated local search (ILS). Results of computational experiments are presented to assess the performance of the proposed algorithms, in comparison with a general purpose solver

    The General Differential Operators Generated by a Quasi-Differential Expressions with their Interior Singular Points

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    The general ordinary quasi-differential expression M of n-th order with complex coefficients and its formal adjoint M + are considered over a regoin (a, b) on the real line, −∞ ≤ a < b ≤ ∞, on which the operator may have a finite number of singular points. By considering M over various subintervals on which singularities occur only at the ends, restrictions of the maximal operator generated by M in L2|w (a, b) which are regularly solvable with respect to the minimal operators T0 (M ) and T0 (M + ). In addition to direct sums of regularly solvable operators defined on the separate subintervals, there are other regularly solvable restrications of the maximal operator which involve linking the various intervals together in interface like style

    The Mediating Role of Psychological Ownership in the Relationship between Ethical Leadership and Organizational Justice, and the Multiple Forms of Employee performance Behaviors

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    In recent years, psychological ownership (PO) has been a growing interest for numerous authors and researchers. However, there is a lack of empirical studies regarding causes and consequences of PO, and a mediating role of PO, especially, in Arab countries. To test research model, data collected from three telecommunication companies working in King Saudi Arabia (KSA). Using a sample of five hundred of employees, 276 completed the survey with response rate 55.2%. The current study concluded several results; First, ethical leadership (EL) and organizational justice (OJ) explained 19.3% of the changes in employees’ psychological ownership. Second, both EL and OJ have a direct effect on PO and indirect effect on IRB and OCB. Third, PO plays a partial mediation between both EL and OJ, and the multiple forms of employee performance behaviors (MFEPB): in-role performance behaviors (IRB) and organizational citizenship behaviors (OCB). Finally, this study provides a set of managerial implications to improve performance in telecommunication companies. As well the current study provides future research suggestions that can be taken into researchers’ interest in human resource management and organizational behavior. Key Words: Psychological Ownership, Ethical leadership, Organizational Justice, Multiple Forms of Employee performance Behavior, The mediating role

    Scenario-based verification and validation of dynamic UML specifications

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    The Unified Modeling Language (UML) is the result of the unification process of earlier object oriented models and notations. Verification and validation (V&V) tasks, as applied to UML specifications, enable early detection of analysis and design flaws prior to implementation. In this work, we address four V&V analysis methods for UML dynamic specifications, namely: Timing analysis and automatic V&V of timing constraints, automated Architectural-level Risk assessment, Performance Modeling and Fault Injection analysis. For each we present: approaches, methods and/or automated techniques. We use two case studies: a Cardiac Pacemaker and a simplified Automatic Teller Machine (ATM) banking subsystem, for illustrating the developed techniques

    ETHNOPHARMACOLOGICAL STUDY OF BRAIN OXIDATIVE STRESS IMPROVING POTENTIAL OF CURCUMIN IN INTOXICATED RATS

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    Objective: The following study aimed to investigate the efficacy of curcumin at preventing amikacin neurotoxicity Methods: Twenty-four&nbsp;male Wister albino rats were randomly divided into four groups including-G (1): control group includes six rats, they were administered 0.5 ml of saline orally for 14 consecutive days.&nbsp;G (2): includes six rats; they were administered 200 mg/kg curcumin orally for 14 consecutive days.&nbsp;G (3):&nbsp;includes six rats, they were administered 300 mg/kg body weight/day of amikacin intraperitoneally for 14 consecutive days G (4):&nbsp;includes six rats, they were administered 200 mg/kg curcumin orally concurrently with 300 mg/kg body weight/day of amikacin. All animals were kept in the same conditions from feed, heat and humidity. Results: According to the result obtained after sacrification of all animals after the end of 14 d, Results revealed that amikacin at the dose rate of 300 mg/kg b. wt for 14 d induces significant changes in oxidative stress markers compared to the control group, a significant reduction in CAT. SOD. GSH (1.51±0.16, 77.00±0.73 and 84.06±4.42) respectively compared to control (3.63±0.11, 98.48±0.18 and 117.05±0.52) along with a significant increase in MDA activity (219.02±3.34) compared to control group (180.42±0.19), That indicate oxidative stress effect of it. On the beneficial side rats received amikacin 300 mg/kg B. wt I/p concurrently with 200 mg/kg b. wt curcumin for successive 14day result in a significant increase in CAT. SOD. GSH (2.23±0.09,92.00±0.26, 102.25±1.71) and decrease in MDA concentration (139.23±3.89) compared to amikacin treated group levels along with histopathological changes appear in brain tissue in the group treated with amikacin include nuclear pyknosis and degeneration in some neurons in the hippocampus, multiple focal eosinophilic plaque formation in the striatum also this results enhanced by activated caspase-3 expression in the brain tissue following amikacin administration. Conclusion: The present study proved that Oral administration of curcumin at the dose of 200 mg/kg for 14 d concurrently with amikacin significantly&nbsp;mitigates its neurotoxic and oxidative stress effects

    On Lw2L^2_w-quasi-derivatives for solutions of perturbed general quasi-differential equations

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    summary:This paper is concerned with square integrable quasi-derivatives for any solution of a general quasi-differential equation of nnth order with complex coefficients M[y]−λwy=wf(t,y[0],…,y[n−1])M[y] - \lambda wy = wf (t, y^{[0]}, \ldots ,y^{[n-1]}), t∈[a,b)t\in [a,b) provided that all rrth quasi-derivatives of solutions of M[y]−λwy=0M[y] - \lambda w y = 0 and all solutions of its normal adjoint M+[z]−λˉwz=0M^+[z] - \bar{\lambda } w z = 0 are in Lw2(a,b)L^2_w (a,b) and under suitable conditions on the function ff

    Investigation of asphaltene under ionic liquid

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    Ionic Liquids are salts with melting temperature below 100 °C. They have fascinating characteristics that made them an eco-friendly replacement for volatile organic solvents. Over years, research has proven the capability of Ionic Liquids to extract heavy metals and organic compounds from water and organic solvents. Researchers have also been able to immobilize Ionic Liquid on Solid support to be used as a catalyst. This study investigates the dissolution of petroleum asphaltenes with ionic liquid. The important parameters governing the ability of ionic liquids for dissolution of asphaltenes are discussed. The ionic liquids based on the cations containing a conjugated aromatic core or the anions which are strong hydrogen bond acceptors are most effective, whereas the ionic liquids containing non coordinating anions such as [BF] and [PF] are nonsolvents for asphaltenes. Increase in the effective anion charge density enhances the ability of ionic liquids to break the extensive asphaltenes associations and thus enhances the solubility of asphaltenes in the ionic liquid. Temperature is found to play an important role on dissolution of asphaltenes and the dissolution can be significantly improved by microwave heating. ii
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