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Multi-Item EOQ Model with Both Demand-Dependent Unit Cost and Varying Leading Time via Geometric Programming  [PDF]
Kotb A. M. Kotb, Hala A. Fergany
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.25072
Abstract: The objective of this paper is to derive the analytical solution of the EOQ model of multiple items with both demand-dependent unit cost and leading time using geometric programming approach. The varying purchase and leading time crashing costs are considered to be continuous functions of demand rate and leading time, respectively. The researchers deduce the optimal order quantity, the demand rate and the leading time as decision variables then the optimal total cost is obtained.
Constrained Probabilistic Continuous Review Inventory System with Mixture Shortage and Stochastic Lead Time Demand
Mona F. El-Wakeel,Hala A. Fergany
Advances in Natural Science , 2013, DOI: 10.3968/j.ans.1715787020130601.1646
Abstract: This paper derives the probabilistic continuous review backorders and lost sales inventory system when the order cost is a function of the order quantity. Our objective is to minimize the expected annual total cost under a restriction on the expected annual holding cost when the lead time demand follows some continuous distributions by using the Lagrangian method. Some published special cases are deduced and an illustrative numerical example with some graphs is added.
PROBABILISTIC (Q,r) INVENTORY MODEL WITH PARTIALLY BACKORDERS WHEN LEAD TIME DEMAND NORMALLY DISTRIBUTED UNDER HOLDING COST RESTRICTION
Mona F. El-Wakeel,Hala A. Fergany
Journal of Global Research in Mathematical Archives , 2013,
Abstract: This paper derives the probabilistic continuous review inventory model that has the two types of shortage when the order cost is a function of the order quantity. The objective is to minimize the expected annual total cost under a constraint on the expected holding cost when the lead time demand follows Normal distribution by using the Lagrangian method. Some published special cases are deduced and a numerical application with illustrative graphs is added.
Probabilistic Periodic Review (Qm, N) Backorders and Lost Sales Inventory Models under Constraint and Varying Holding Cost and Normally Distributed Protection Interval Demand
Hala Aly Fergany,Naglaa Hassan El-Sodany
Journal of Modern Mathematics and Statistics , 2012, DOI: 10.3923/jmmstat.2011.71.79
Abstract: This study derives the probabilistic periodic review Backorders and Lost sales inventory models when the holding cost is a function of the inventory cycle. The expected total cost is composed of four components; the expected purchase cost, the expected ordering cost, the expected reviewing cost, the expected holding cost and the expected shortage cost. The objective is to minimize the expected annual total cost under a restriction on the expected annual reviewing cost when the protection interval demand follows the normal distribution. The Lagrangian multipliers are used to solve this constrained model in a closed form. Finally, some special cases are deduced and an illustrative numerical example is added with some graphs.
Spatial Modeling of Optimum Zones for Wind Farms Using Remote Sensing and Geographic Information System, Application in the Red Sea, Egypt  [PDF]
Hala A. Effat
Journal of Geographic Information System (JGIS) , 2014, DOI: 10.4236/jgis.2014.64032
Abstract:

Wind power is a safe form of renewable energy and is one of the most promising alternative energy sources. Worldwide, the wind power industry has been rapidly growing recently. It is crucial that the locating of new projects must address both environmental and social concerns. The Red Sea shoreline in Egypt provides excellent wind power potential sites for the Red Sea Governorate. In this study, appropriate zones for wind power farms were mapped using remotely sensed data and a GIS-based model namely Spatial Multi-Criteria Evaluation (SMCE). This model incorporated several criteria, two sets of factors and a set of constraints. First, resource factors included wind speed, elevation zones used to derive the wind power density. Second, economic factors included distances from urban areas, roads and power-lines. Third, land constraints were excluded from the evaluation. The land constraints set included land slope angles, shoreline, urban areas, protectorates airports and ecologically sensitive and historical areas. The Analytical Hierarchy Process was used to assign the criteria relative weights. The weighted criteria and constraints maps were combined in the MCE model. The model identified the zones with potential wind power energy. Such zones were found to exist along the northern parts of the Red Sea shoreline. Some of which are unsuitable due to their location within a sensitive eco-system, high slopes and/or a nearby airport. By excluding such land constrains, the model identified the most appropriate zones satisfying all assigned suitability conditions for wind farms. Ideal zones amount to 706 sq. km with suitability values ranging from 83% to 100% and highly suitable zones amount to 3781 sq. km having suitability values ranging from 66% to 83%.

Knowledge of Fathers’ Support during Labor: From Arabic Fathers’ Perspective  [PDF]
Hala A. Bawadi
Health (Health) , 2015, DOI: 10.4236/health.2015.711168
Abstract: Aim: The aim of this study was to assess the kind of labor support Arab fathers could offer their wives. Design and Method: An interpretative phenomenological approach was used to reveal the meaning attributed by Arabic fathers regarding their support during labor. Individual, semi-structured interviews were conducted with 19 Arabic fathers. The analysis was done by using Smith’s model of interpretive phenomenological analysis (IPA) together with software package NVivo7. Findings: The analysis of the interviews illustrated the types of labor support offered by Arabic fathers to their wives. Three main themes emerged from the data: physical support, emotional support, and spiritual support. Conclusion: The support offered by Arabic fathers was in the minimal degree and missing practical support. Socio cultural issues and health policies prevented fathers from playing an active role during labor. There is a need to develop policies and regulations that enhance more inclusion of fathers in maternity services including the labor room.
DESIGN AND OPTIMIZE SUBSTATION GROUNDING GRID BASED ON IEEE STD. 80 - 2000 USING GUI AND MATLAB CODES
Dr. ATTIA A. EL-FERGANY
International Journal of Engineering Science and Technology , 2011,
Abstract: Substation grounding grid design requires a simple, but accurate tool to compute the parameters that guarantees safety of personnel during earth faults. In this article, a Graphical User Interface (GUI) with an interactive computer program using MATLAB 7.10 version has been developed. The developed tool allows the computations of the total grid conductor length required for the earth grid to meet the step and touch potential criterion for safety. The interactive method versatility has allowed configuring the grid according to theavailability of land space and value of the native soil resistivity. Calculations of minimum cross sectional Area of grounding conductors are presented. Simple Optimization technique using iterative search are applied to optimal design of grounding grid (conductors and rods as well) to satisfy tolerable safe touch and step voltages. Inequality constraints of ground potential rise (GPR), ground resistance (Rg), step voltage (Estep) and touch voltage (Etouch), are based on latest edition of ANSI/IEEE Std. 80-2000. The viability of results of developed tool are compared with world-wide software’s like ETAP and CYMGRD and showed to be reliable, friendly user interface, easy and practical tool for calculations of Ground grid design. All approved shapes (Square, Rectangle, Triangle, L and T shapes) based on IEEE 80 guidelines and procedures are implemented and tested. Executable versions may be obtained after generating C/C++ plus header files code from MATLAB codes to run standalone.
Modeling and Mapping of Urban Sprawl Pattern in Cairo Using Multi-Temporal Landsat Images, and Shannon’s Entropy  [PDF]
Hala A. Effat, Mohamed A. El Shobaky
Advances in Remote Sensing (ARS) , 2015, DOI: 10.4236/ars.2015.44025
Abstract: Cairo city, being the Egypt’s industrial and cultural center, has a problem of rapid urban sprawl. The city has an extremely high population density which is continuously increasing through informal settlements that grow by sprawling due to migration from the Nile Delta villages and the high population growth rates. The present study attempts to understand, detect and quantify the spatial pattern of Cairo’s urban sprawl using Shannon’s entropy and multi-temporal Landsat TM and ETM images acquired for the period from 1984 to 2013. Supervised classification was applied to extract the built-up areas and to measure the changes in the urban land-use class among the city wards. Shannon’s entropy was applied to model the city’s urban sprawl, trend and spatial change. The entropy values for the city’s electoral wards were modeled and used in an interpolation function to create an entropy surface (index) for each acquired temporal image. Such index indicates the spatial pattern of the urban sprawl and provides a visual comparison of the entropy phenomenon in such wards. Results indicate that Shannon’s entropy index increased from (1.4615) in year 1984 to (2.1023) in year 2013, indicating more dispersed urban growth, a sign of urban sprawl. The maximum entropy values are found in the eastern wards namely El Nozha, Awal Nasr District, Thany Nasr-District, El Salam, El Marg and El Bassatein. A regression analysis was carried for the population growth rate and the built-up areas. Findings help in understanding the sprawl patterns and dynamics among Cairo’s electoral wards and provide a visual comparison. The applied methodology provides explanations and facilitates tracing and measuring the urban sprawl which is needed by decision makers and city planners of mega cities.
A Multidisciplinary Approach to Mapping Potential Urban Development Zones in Sinai Peninsula, Egypt Using Remote Sensing and GIS  [PDF]
Hala A. Effat, Mohamed N. Hegazy
Journal of Geographic Information System (JGIS) , 2013, DOI: 10.4236/jgis.2013.56054
Abstract:

One of the main concerns of physical planning is the proper designation of suitable sites for feasible and sustainable land use. A main importance of such issue is that it withdraws attention to the necessity of adopting a multidisciplinary approach to the zoning and site selection problem. Egypt has a top priority objective to develop Sinai Peninsula and to create new sustainable and attracting communities that should ensure a stable, economic and sustainable environment in vast desert zones. Due to the difficulty in solving a zoning problem in a desert, the use of remote sensing and Geographic Information System (GIS) was to explore the desert potentials in the region. Five sub-models were created for five themes using Spatial Multicriteria Analysis (SMCA) and used as inputs to the final suitability model. These themes are: land resources, land stability, accessibility, cost of construction and land protection. A GIS-based model was designed following a sustainable development approach. Economic, social and environmental factors were introduced in the model to identify and map land suitable zones for urban development using Analytical Hierarchy Process (AHP). The suitability index map for urban development was produced by weighted overlay of the five sub-models themes. The most suitable zones for urban development in Sinai Peninsula amounted to 5327 square kilometers representing 17% of total area, whereas high suitable zones reached 40% indicating a high suitability of Sinai Peninsula lands for residing new urban communities.

 

Emission/Economic Load Dispatch Using Combination of Evolutionary Algorithms
Attia A. El-Fergany,Mahdi El-Arini
International Journal of Soft Computing , 2012, DOI: 10.3923/ijscomp.2012.256.263
Abstract: This study presents an integrating Genetic Algorithm (GA) and Pattern Search (PS) approaches to solve the Combined Emission/Economic Dispatch (CEED) problems with multi-objectives have been developed. This integration will combine the strengths of GA and PS to solve this problem. The PS performance is highly dependent on the initial/starting point. To tackle this issue, GA was utilized to initiate the starting point for PS and to validate the obtained result of PS as well. The weighted multi-objective function with penalty factor is used in this study. The proposed weighting factor plays significant part on the problem solution. The proposed methodology considers operational power constraints of generating units, value-point loading ripple effects with non-convex characteristics and line losses as well for practical applications. The proposed integrating algorithms were intensively demonstrated, tested and verified on several cases. The obtained results prove high quality and effectiveness of proposed integrated GA-PS algorithm to solve CEED problems with reduced execution time.
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