Beyond LIFO and FIFO: Exploring an Allocation-In-Fraction-Out (AIFO) policy in a two-warehouse inventory model

The classical formulation of a two-warehouse inventory model is often based on the Last-In-First-Out (LIFO) or First-In-First-Out (FIFO) dispatching policy. The LIFO policy relies upon inventory stored in a rented warehouse (RW), with an ample capacity, being consumed first, before depleting inventory of an owned warehouse (OW) that has a limited capacity. Consumption works the other way around for the FIFO policy. In this paper, a new policy entitled “Allocation-In-Fraction-Out (AIFO)” is proposed. Unlike LIFO and FIFO, AIFO implies simultaneous consumption fractions associated with RW and OW. That said, the goods at both warehouses are depleted by the end of the same cycle. This necessitates the introduction of a key performance indicator to trade-off the costs associated with AIFO, LIFO and FIFO. Consequently, three general two-warehouse inventory models for items that are subject to inspection for imperfect quality are developed and compared – each underlying one of the dispatching policies considered. Each sub-replenishment that is delivered to OW and RW incurs a distinct transportation cost and undertakes a 100 per cent screening. The mathematical formulation reflects a diverse range of time-varying forms. The paper provides illustrative examples that analyse the behaviour of deterioration, value of information and perishability in different settings. For perishable products, we demonstrate that LIFO and FIFO may not be the right dispatching policies. Further, relaxing the inherent determinism of the maximum capacity associated with OW, not only produces better results and implies comprehensive learning, but may also suggest outsourcing the inventory holding through vendor managed inventory

Efficient inventory control for imperfect quality items

In this paper, we present a general EOQ model for items that are subject to inspection for imperfect quality. Each lot that is delivered to the sorting facility undertakes a 100 per cent screening and the percentage of defective items per lot reduces according to a learning curve. The generality of the model is viewed as important both from an academic and practitioner perspective. The mathematical formulation considers arbitrary functions of time that allow the decision maker to assess the consequences of a diverse range of strategies by employing a single inventory model. A rigorous methodology is utilised to show that the solution is a unique and global optimal and a general step-by-step solution procedure is presented for continuous intra-cycle periodic review applications. The value of the temperature history and flow time through the supply chain is also used to determine an efficient policy. Furthermore, coordination mechanisms that may affect the supplier and the retailer are explored to improve inventory control at both echelons. The paper provides illustrative examples that demonstrate the application of the theoretical model in different settings and lead to the generation of interesting managerial insights

Integration of radiometric ground-based data and high-resolution quickbird imagery with multivariate modeling to estimate maize traits in the nile delta of Egypt

In site-specific management, rapid and accurate identification of crop stress at a large scale is critical. Radiometric ground-based data and satellite imaging with advanced spatial and spectral resolution allow for a deeper understanding of crop stress and the level of stress in a given area. This research aimed to assess the potential of radiometric ground-based data and high-resolution QuickBird satellite imagery to determine the leaf area index (LAI), biomass fresh weight (BFW) and chlorophyll meter (Chlm) of maize across well-irrigated, water stress and salinity stress areas in the Nile Delta of Egypt. Partial least squares regression (PLSR) and multiple linear regression (MLR) were evaluated to estimate the three measured traits based on vegetation spectral indices (vegetation-SRIs) derived from these methods and their combination. Maize field visits were conducted during the summer seasons from 28 to 30 July 2007 to collect ground reference data concurrent with the acquisition of radiometric ground-based measurements and QuickBird satellite imagery. The results showed that the majority of vegetation-SRIs extracted from radiometric ground-based data and high-resolution satellite images were more effective in estimating LAI, BFW, and Chlm. In general, the vegetation-SRIs of radiometric ground-based data showed higher R2 with measured traits compared to the vegetation-SRIs extracted from high-resolution satellite imagery. The coefficient of determination (R2) of the significant relationships between vegetation-SRIs of both methods and three measured traits varied from 0.64 to 0.89. For example, with QuickBird high-resolution satellite images, the relationships of the green normalized difference vegetation index (GNDVI) with LAI and BFW showed the highest R2 of 0.80 and 0.84, respectively. Overall, the ground-based vegetation-SRIs and the satellite-based indices were found to be in good agreement to assess the measured traits of maize. Both the calibration (Cal.) and validation (Val.) models of PLSR and MLR showed the highest performance in predicting the three measured traits based on the combination of vegetation-SRIs from radiometric ground-based data and high-resolution QuickBird satellite imagery. For example, validation (Val.) models of PLSR and MLR showed the highest performance in predicting the measured traits based on the combination of vegetation-SRIs from radiometric ground-based data and high-resolution QuickBird satellite imagery with R2 (0.91) of both methods for LAI, R2 (0.91–0.93) for BFW respectively, and R2 (0.82) of both methods for Chlm. The models of PLSR and MLR showed approximately the same performance in predicting the three measured traits and no clear difference was found between them and their combinations. In conclusion, the results obtained from this study showed that radiometric ground-based measurements and high spectral resolution remote-sensing imagery have the potential to offer necessary crop monitoring information across well-irrigated, water stress and salinity stress in regions suffering lack of freshwater resources

Triple-Band Metamaterial Inspired Antenna for Future Terahertz (THz) Applications

For future healthcare in the terahertz (THz) band, a triple-band microstrip planar antenna integrated with metamaterial (MTM) based on a polyimide substrate is presented. The frequencies of operation are 500, 600, and 880 GHz. The triple-band capability is accomplished by etching metamaterial on the patch without affecting the overall antenna size. Instead of a partial ground plane, a full ground plane is used as a buffer to shield the body from back radiation emitted by the antenna. The overall dimension of the proposed antenna is 484×484 μm2. The antenna's performance is investigated based on different crucial factors, and excellent results are demonstrated. The gain for the frequencies 500, 600, 880GHz is 6.41, 6.77, 10.1 dB, respectively while the efficiency for the same frequencies is 90%, 95%, 96%, respectively. Further research has been conducted by mounting the presented antenna on a single phantom layer with varying dielectric constants. The results show that the design works equally well with and without the phantom model, in contrast to a partially ground antenna, whose performance is influenced by the presence of the phantom model. As a result, the presented antenna could be helpful for future healthcare applications in the THz band

A Sustainable Closed-Loop Supply Chains Inventory Model Considering Optimal Number of Remanufacturing Times

The mathematical modeling of reverse logistics inventory systems ignores the fact that returned items may arrive out of sequence, i.e., with different number of remanufacturing times. Moreover, such modeling assumes that the retuned items may retain the same quality upon recovery regardless of how many times they have been previously remanufactured. This paper develops a new mathematical expression of the percentage of retuned items that can be remanufactured a finite number of times. The proposed expression is modeled as a function of the expected number of times an item can be remanufactured in its lifecycle and the number of times an item can be technologically (or optimally) remanufactured based on its quality upon recovery. The model developed in this paper considers joint production and remanufacturing options. The return rate is a varying demand-dependent rate, which is a decision variable with demand, product deterioration, manufacturing, and remanufacturing rates being arbitrary functions of time. The model considers the initial inventory of returned items in the mathematical formulation, which enables decision-makers to adjust all functions and input parameters for subsequent cycles. Illustrative examples indicate that dependent purchasing price of recovery items and the incorporation of remanufacturing investment cost significantly impact the optimal remanufacturing policy

The impact of the green Middle East initiative on sustainable development in the Kingdom of Saudi Arabia

Using econometric analysis, this study intended to determine the influence of the Green Middle East Initiative on sustainable development in the Kingdom of Saudi Arabia from 2000 to 2020. This research yielded a number of findings, the most important of which are: The country has tended to reduce carbon emissions by increasing natural gas use and decreasing diesel and crude oil use in electricity generation. The real per capita income increased by 0.8 percent annually due to the unpredictability and instability of the economic growth rate. The Human Development Index has similarly risen, from 0.744 in 2000 to 0.855 in 2020. It was also discovered that a 10% increase in domestic refined petroleum product consumption results in a 7.97% rise in carbon dioxide emissions. And that a 10% rise in predicted carbon dioxide emissions results in 4.71 percent, 0.36 percent, and 0.71 percent decreases in foreign direct investment, real GDP, and the value of the human development index, respectively. And the Green Middle East initiative included planting 10 billion trees irrigated with untapped treated sewage water amounting to 1528.49 million m3, with a value of 2.094 billion riyals. Finally, the gradual transformation of the green economy leads to environmental sustainability and integration between the environment, economic, and social dimensions of sustainable development, and then this study recommends the necessity of following up and evaluating the results of the work of the Green Middle East Initiative so that carbon emissions eliminated in the Kingdom of Saudi Arabia until 2060

Successful treatment of multi-focal XDR tuberculous osteomyelitis

Summary: We herein describe the nosocomial transmission of a pre-XDR or MDR case of pulmonary tuberculosis in a HIV-negative health care worker in an area endemic for MDR and XDR tuberculosis. Following inadequate therapy and non-compliance, he presented with extra-pulmonary XDR tuberculosis in the form of multi-focal osteomyelitis and encysted pleural effusion. He was cured after two years of treatment with various anti-tuberculous drugs in addition to interferon gamma. Keywords: XDR tuberculosis, Osteomyelitis, Therap

Preference and Values of Stroke Interventions, Kingdom of Saudi Arabia

Background. Acute ischemic stroke (AIS) occurs when there is a sudden occlusion of the arterial blood supply to part of the brain resulting in sudden focal neurological deficits. Recent major clinical trials of reperfusion therapy had proved the efficacy of timely stroke intervention to restore blood flow. Development of acute stroke protocols waiving the informed consent to obtain necessarily brain images or provide thrombolytic therapy is important to streamline and organize efforts to achieve the goal of early intervention and better functional outcome. Objective. This study aims to identify the preference and values of acute stroke interventions standard of care therapy without informed consent in the absence of surrogate decision-makers. Methods. A cross-sectional survey was conducted in the Kingdom of Saudi Arabia using an electronic questionnaire. The questionnaire addressed the patients' preference of acute stroke protocol waiving the informed consent for hyperacute brain images and delivering thrombolytic therapy or mechanical thrombectomy in absence of surrogate. All Saudi population aging from 18 to 65 years were invited to participate. Results. The study included 2004 participants with ages ranging from 18 to 65 years with mean age of 30.1 years. About 66% of the participants were females and 95% were Saudi. Overall, 90.5% of the participants agreed on performing computed tomography angiography (CTA) by the medical staff for the acute strokes without consenting followed by 79% for thrombolytic therapy, 70.8% for mechanical thrombectomy, and only 49.3% for acute lifesaving surgical intervention. Conclusion. Researchers found that the high percentage of participants had favorable response and positive perception toward providing acute stroke intervention and mechanical thrombectomy without informed consent. However, the study showed skeptical acceptance among participants regarding invasive surgical measures

Optic Nerve Involvement in Farber Lipogranulomatosis: Expanding the Phenotypic Spectrum

Farber lipogranulomatosis (Farber disease [FD], MIM 228000) is a rare autosomal recessive lysosomal storage disorder caused by a deficiency of acid ceramidase (AC) and is linked to ASAH1 gene mutations. ASAH1 mutations can lead to severe reduction in AC activity that causes accumulation of ceramides in various body tissues including the retina. The onset of clinical manifestations usually occurs during infancy, and the severity depends on residual ceramidase activity. Classic clinical features of FD include painful joint swelling, progressive dysphonia, and subcutaneous nodules. We report 2 unrelated patients presenting with classic FD phenotype who shared the same homozygous pathogenic mutation in the ASAH1 gene and optic neuropathy, thereby expanding the FD phenotypic spectrum