scholarly journals Optimal Replenishment and Lot Sizing Strategy for Inventory Mechanism with Step-Shaped Demand and Backordering

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Lixia Zhang ◽  
Lili Han
Keyword(s):  
Lot Sizing ◽  
Closed Form Solution ◽  
Planning Horizon ◽  
Form Solution ◽  
Inventory Cost ◽  
Second Stage ◽  
Demand Rate ◽  
Two Stages ◽  
The Given ◽  
Infinite Planning Horizon

This paper discusses the inventory mechanism with backordering and with the infinite planning horizon consisting of two stages wherein the demand rate in the first stage is strictly greater than that in the second stage. To minimize the retailer’s inventory cost, we establish a lot sizing decision model. On the basis of the inventory cost analysis, we present a closed-form solution to the model and provide an optimal replenishment and stocking strategy to the retailer. The given numerical experiments show the validity of the model.

scholarly journals Retailer’s Emergency Ordering Policy when Facing an Impending Supply Disruption

2021 ◽  
Vol 13 (13) ◽  
pp. 7041
Author(s):  
Jingfu Huang ◽  
Gaoke Wu ◽  
Yiju Wang
Keyword(s):  
Optimization Model ◽  
Numerical Experiments ◽  
Closed Form Solution ◽  
Form Solution ◽  
Model Solution ◽  
Inventory Cost ◽  
Supply Disruption ◽  
Procurement Policy ◽  
Ordering Policy ◽  
Procurement Strategies

Supply disruption is a common phenomenon in business activities. For the case where the supply disruption is predictable, the retailer should make an emergency procurement beforehand to decrease the inventory cost. For the scenario such that the happening time of the supply disruption obeys a certain common probability distribution but the ending time of the supply disruption is deterministic, based on minimizing the inventory cost and under two possible procurement strategies, we establish an emergency procurement optimization model. By considering the model solution in all cases, we establish a closed-form solution to the optimization model and provide an optimal emergency procurement policy to the retailer. Some numerical experiments are made to test the validity of the model and the effect of the involved parameters on the emergency procurement policy.

scholarly journals Evaluating the parameters of a mobile maize dryer in practice

2013 ◽  
Vol 61 (6) ◽  
pp. 1779-1784
Author(s):  
Josef Los ◽  
Jiří Fryč ◽  
Zdeněk Konrád
Keyword(s):  
Large Scale ◽  
Electric Energy ◽  
Operating Parameters ◽  
The Czech Republic ◽  
Maize Hybrids ◽  
Post Harvest ◽  
Second Stage ◽  
Energy Intensiveness ◽  
Two Stages ◽  
The Given

The method of drying maize for grain has been recently employed on a large scale in the Czech Republic not only thanks to new maize hybrids but also thanks to the existence of new models of drying plants. One of the new post-harvest lines is a plant in Lipoltice (mobile dryer installed in 2010, storage base in 2012) where basic operational measurements were made of the energy intensiveness of drying and operating parameters of the maize dryer were evaluated. The process of maize drying had two stages, i.e. pre-drying from the initial average grain humidity of 28.55% to 19.6% in the first stage, and the additional drying from 16.7% to a final storage grain humidity of 13.7%. Mean volumes of natural gas consumed per 1 t% for drying in the first and second stage amounted to 1.275 m3 and 1.56 m3, respectively. The total mean consumption of electric energy per 1 t% was calculated to be 1.372 kWh for the given configuration of the post-harvest line.

Comments on Two Models for Operating Two-Warehouse Inventory Systems with Deteriorating Items and Inflationary Effects

2011 ◽  
Vol 2 (2) ◽  
pp. 1-21
Author(s):  
Huachun Xiong ◽  
Jinxing Xie ◽  
Bo Niu
Keyword(s):  
Infinite Horizon ◽  
Planning Horizon ◽  
Inventory Systems ◽  
Traditional Model ◽  
Present Value ◽  
Total Cost ◽  
Demand Rate ◽  
Replenishment Cycle ◽  
The Cost ◽  
Infinite Planning Horizon

This paper deals with the two-warehouse partial backlogging inventory problems under inflation for a deteriorating product with a constant demand rate over an infinite horizon. In contrast to the traditional model in which each replenishment cycle starts with an instant replenishment and ends with shortages, an alternative model is proposed in recent literature in which each cycle starts with shortages. It is proven to be less expensive to operate than the traditional model in terms of the present value of the cost per unit time. The present paper points out that the criteria of minimizing the cost per unit time is unreasonable when the inflationary effect is taken into consideration, and instead, the criteria of minimizing the present value of the total cost over the whole infinite planning horizon should be used. The objective functions of these two models are changed and proved that the model with shortages at the start of the cycle is less expensive to operate than the traditional model in terms of the present value of the total cost, but the optimal solutions of the models minimizing the cost per unit time indicate significantly higher total costs.

Comments on Two Models for Operating Two-Warehouse Inventory Systems with Deteriorating Items and Inflationary Effects

2013 ◽  
pp. 349-370
Author(s):  
Huachun Xiong ◽  
Jinxing Xie ◽  
Bo Niu
Keyword(s):  
Infinite Horizon ◽  
Planning Horizon ◽  
Inventory Systems ◽  
Traditional Model ◽  
Present Value ◽  
Total Cost ◽  
Demand Rate ◽  
Replenishment Cycle ◽  
The Cost ◽  
Infinite Planning Horizon

This paper deals with the two-warehouse partial backlogging inventory problems under inflation for a deteriorating product with a constant demand rate over an infinite horizon. In contrast to the traditional model in which each replenishment cycle starts with an instant replenishment and ends with shortages, an alternative model is proposed in recent literature in which each cycle starts with shortages. It is proven to be less expensive to operate than the traditional model in terms of the present value of the cost per unit time. The present paper points out that the criteria of minimizing the cost per unit time is unreasonable when the inflationary effect is taken into consideration, and instead, the criteria of minimizing the present value of the total cost over the whole infinite planning horizon should be used. The objective functions of these two models are changed and proved that the model with shortages at the start of the cycle is less expensive to operate than the traditional model in terms of the present value of the total cost, but the optimal solutions of the models minimizing the cost per unit time indicate significantly higher total costs.

Study of Cyclization of 1-Benzoyl-3-methyl-3-(2-methoxycarbonylphenyl)thiourea to 1-Methyl-2-thioxo-4-quinazolone

1993 ◽  
Vol 58 (5) ◽  
pp. 1122-1132 ◽  
Author(s):  
Jaromír Kaválek ◽  
Vladimír Macháček ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Study ◽  
Title Reaction ◽  
Initial Substance ◽  
Second Stage ◽  
Rate Determining Step ◽  
Benzoyl Group ◽  
Two Stages ◽  
The Given

The reaction mechanism of the title reaction was proposed on the bases of the kinetic study. The reaction takes place in two stages considerably differing in rates. In the first, faster stage, the anion of initial substance cyclizes to 1-methyl-3-benzoyl-2-thioxo-4-quinazolone. The reaction is reversible, the concentration of 1-methyl-3-benzoyl-2-thioxo-4-quinazolone decreases with increasing concentration of methanolate. In the second stage, the benzoyl group rearrangement in the given substance from nitrogen to sulfur and subsequent methanolysis to 1-methyl-2-thioxo-4-quinazolone take place. The rate-determining step is the methanolysis for [CH3O(-)] < 4 . 10-3 mol l-1 and the benzoyl group rearrangement for higher methanolate concentrations.

scholarly journals Investigating pre-service science teachers’ laboratory approach choices

2016 ◽  
Vol 8 (1) ◽  
pp. 61 ◽  
Author(s):  
Nurhan ÖZTÜRK GEREN ◽  
Esra BOZKURT ALTAN ◽  
Serhat ERCAN
Keyword(s):  
Science Teachers ◽  
Science Curriculum ◽  
Service Science ◽  
Science Laboratory ◽  
Structured Interviews ◽  
Inquiry Based Learning ◽  
Second Stage ◽  
Two Stages ◽  
The Given ◽  
Selection Of

The main focus of the current study was to determine what kind of laboratory approaches will be designed how this process will be evaluated by pre-service teachers. The study was carried out on the basis of a qualitative paradigm. The study group of the research consisted of 40 pre-service science teachers. In the current study, the application was conducted within the Laboratory Applications in Science I-II courses at two stages. The per stage was conducted in 14 weeks (four hours per weeks). The first stage of the process (14 weeks) started with a theoretical presentation introducing laboratory approaches and was conducted with the guidance of five experiment manuals designed on the basis of different laboratory approaches ranging from a confirmatory laboratory approach to an inquiry-based learning by the researcher. In the second stage, the pre-service teachers were asked to examine the units and objectives of the Science Curriculum Program and then were asked to select a laboratory approach and set the objectives to design an activity manual. The pre-service teachers worked for five weeks to determine the objectives, find the appropriate approach and design an experiment manual in line with the selected approach. Then, each group conducted the laboratory class under the guidance of their experiment manual that they had developed for each week. The data of the study was collected within two periods through the difficulties experienced, skills attained through the process, reflective texts presenting course-related suggestions and semi-structured interviews. It was determined that the students experienced some difficulties in the selection of the laboratory approach for the given topic and the design of experiment manuals; they preferred inquiry-based learning laboratory activities as they were believed to be more effective and administration of experiment manuals to peers were believed to be conducive to professional development.Keywords:Laboratory applications in science, laboratory approaches, pre-service science teachers 

Analysis of Performance of Pneumatic Impact Absorbers

1978 ◽  
Vol 100 (2) ◽  
pp. 236-241 ◽  
Author(s):  
M. S. Hundal
Keyword(s):  
Nonlinear Differential Equations ◽  
Closed Form Solution ◽  
Form Solution ◽  
Initial Portion ◽  
Orifice Area ◽  
Fixed Area ◽  
And Performance ◽  
Two Stages ◽  
Mass Spring ◽  
Integrated Performance

Performance of impact absorbers employing a pneumatic damper and a linear spring in parallel is analyzed. The governing nonlinear differential equations are derived and converted to nondimensional form. For case of a damper with fixed area orifice the equations are numerically integrated. Performance charts are presented in terms of three dimensionless parameters: mass, spring stiffness and orifice area ratio. Then, a second case is considered in which the damper orifice area is made to vary in two stages. During an initial portion of the stroke the orifice is closed and the air pressure rises to a certain value. In the second stage the orifice area varies in such a manner that a constant deceleration of the mass is achieved. A closed form solution of the governing equations is presented for the second case. The design and performance are compared with that of an impact absorber consisting of a spring only, and with those employing hydraulic dampers.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

Distributed Entropy Energy-Efficient Clustering algorithm for cluster head selection (DEEEC)

2020 ◽  
Vol 39 (6) ◽  
pp. 8139-8147
Author(s):  
Ranganathan Arun ◽  
Rangaswamy Balamurugan
Keyword(s):  
Energy Efficient ◽  
Clustering Algorithm ◽  
Cluster Head ◽  
Residual Energy ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Second Stage ◽  
Energy Efficient Clustering ◽  
Two Stages ◽  
Ch Selection

In Wireless Sensor Networks (WSN) the energy of Sensor nodes is not certainly sufficient. In order to optimize the endurance of WSN, it is essential to minimize the utilization of energy. Head of group or Cluster Head (CH) is an eminent method to develop the endurance of WSN that aggregates the WSN with higher energy. CH for intra-cluster and inter-cluster communication becomes dependent. For complete, in WSN, the Energy level of CH extends its life of cluster. While evolving cluster algorithms, the complicated job is to identify the energy utilization amount of heterogeneous WSNs. Based on Chaotic Firefly Algorithm CH (CFACH) selection, the formulated work is named “Novel Distributed Entropy Energy-Efficient Clustering Algorithm”, in short, DEEEC for HWSNs. The formulated DEEEC Algorithm, which is a CH, has two main stages. In the first stage, the identification of temporary CHs along with its entropy value is found using the correlative measure of residual and original energy. Along with this, in the clustering algorithm, the rotating epoch and its entropy value must be predicted automatically by its sensor nodes. In the second stage, if any member in the cluster having larger residual energy, shall modify the temporary CHs in the direction of the deciding set. The target of the nodes with large energy has the probability to be CHs which is determined by the above two stages meant for CH selection. The MATLAB is required to simulate the DEEEC Algorithm. The simulated results of the formulated DEEEC Algorithm produce good results with respect to the energy and increased lifetime when it is correlated with the current traditional clustering protocols being used in the Heterogeneous WSNs.

Sign in / Sign up

Export Citation Format

Share Document