Linear programming (LP, or linear optimization) is a method to
achieve the best outcome (such as maximum profit or lowest cost) in a mathematical model whose requirements are represented by linear relationships. Linear programming is a special case
of mathematical programming (mathematical optimization).
More formally, linear programming is a technique for the
optimization of a linear objective function, subject to linear equality and linear inequality constraints. Its feasible region is a convex polyhedron, which is a set defined as the intersection of finitely many half spaces, each of which is defined by a linear inequality. Its objective function is a real-valued affine function defined on this polyhedron. A linear programming algorithm finds a point in the polyhedron where this function has the smallest (or largest) value if such a point exists.
Reactive power compensation in distribution networks is one of the most important economic and
environmental issues in power system studies. In this paper the following points are investigated:
· The characteristics of the most developed equipment
used for reactive power compensation.
· Equations used in ETAP program calculation
· OCP is part of ETAP program which gives us the possibility to determine optimal reactive power
sizing and placement in distribution networks in order to achieve optimal Power loss and distribution
power system enhancement.
· ETAP program is applied on a part of Damascus suburb electrical network which was simulated by its
real parameters and the positive economical and technical results have been clarified.
In this study, basic methodologies of the GA and the scaling
procedures are summarized, the scaling criteria of real time history
records to satisfy the Syrian design code are discussed. The
traditional time domain scaling procedures and the scali
ng
procedures using GA are utilized to scale a number of the available
real records to match the Syrian design spectra. The resulting time histories of the procedures are investigated and compared in terms of meeting criteria.
Ten randomized samples of materials were collected from two
places (Damascus, Homs)in Syria for isolation and identification
yeasts. These yeasts were classified morphologically according to
Barnett's and physiologically by API technique .Results
showed
that 6 isolated yeasts were Saccharomyces cerevisiae . These
isolated yeasts were screened to investigate production of biomass.
The results showed that there were differences in the ability of
isolated yeasts to produce biomass. Saccharomyces cerevisiae
isolated from date fruit was best yeast for biomass production.
This research presents new procedures to calculate the aggregates weight and the water requirement to realize a controlled concrete mixing design, where the aggregates proportion is defined by numerical method according to referential curve draw as r
eferring to the proposed fine aggregate ratio and the required water will be calculated as referring to the aggregates surface area. The results showed the facility and the reliability of the proposed design procedures.
: Nonlinear response history evaluation is becoming a practical tool due to availability of high performance computing and recommendations of the new seismic guidelines, and due to the increase of available strong ground motion database. When testing
the selected and scaled ground motions, it’s a standard procedure to use the time history analysis to validate the results in terms of structural responses and their variation. this proves the efficiency of the presented procedure.
In this study the selection and scaling criteria of real time history records to satisfy the Syrian design code are discussed. Ten set of records have been selected and scaled, every set consists of seven records of available real records, to match the Syrian design spectra. The resulting time histories are investigated and compared in terms of suitability as input to time history analysis of civil engineering structures, by mean of time history analyses of SDOF systems which are conducted to examine the efficiency of the scaling method in reducing the scatter in structural response. The nonlinear response of SDOF systems is represented by bilinear hysteretic model. Assuming 5 different Periods, α=3% post-yield stiffness, a number of 700 runs of analysis are conducted. And a number of 280 runs of analysis are conducted for MDOF systems.
Structural design for seismic loading, which is traditionally done for most types of common structures by the means of equivalent lateral static loading or modal spectrum analysis, is no longer a preferred methodology for design of modern structures
with complex topology and functionality under extreme loading scenarios. Nonlinear response history evaluation, on the other hand, is becoming a practical tool due to availability of high performance computing and recommendations of the new seismic guidelines, and due to the increase of available strong ground motion database. Therefor using and scaling real recorded accelerograms is becoming one of the most contemporary research issues in this field.
Seismological characteristics of the records, such as earthquake magnitude, epicentral distance and site classification are usually considered in the selection of real records, as they influence the shape of the response spectrum, the energy content and duration of strong ground shaking, and therefore the expected demand on structures. After real seismic records selection it is necessary to scale these records to match the intensity of the earthquake expected for the site. Generally, scaling can be made by ground motions uniform scaling in time domain which is simply scaled up or down the ground motions uniformly to best match (in average) the target spectrum within a period range of interest. It’s an engineer’s job to find the best scaling factors to best match the target spectrum, which is a complex task, so we employed the Genetic Algorithm (GA) in finding them to achieve the best results.
When testing the selected and scaled ground motions, it’s a standard procedure to use the nonlinear time history analysis to validate the results in terms of structural responses and their variation. this proves the efficiency of the presented procedure.
In this study, basic methodologies for selecting and scaling strong ground motion time histories are summarized, the selection and scaling criteria of real time history records to satisfy the Syrian design code are discussed. The GA scaling procedures are utilized to scale 10 set of records, every set consists of seven records of available real records to match the Syrian design spectra. The resulting time histories are investigated and compared in terms of suitability as input to time history analysis of civil engineering structures, by mean of time history analyses of SDOF systems which are conducted to examine the efficiency of the scaling method in reducing the scatter in structural response. The nonlinear response of SDOF systems is represented by bilinear hysteretic model. Assuming 5 different Periods, yield strength reduction factor, R= 4.5, α=3% post-yield stiffness, a number of 700 runs of analysis are conducted. The results are described for elastic displacement D.
A model has been developed for optimal reservoir operation system of Alfatha dam upstream Samerra
Barrage which is considered as a strategic node in the Tigris river system in Iraq. This model is based on
combining an optimization dynamic programmi
ng model with a flood routing simulation model within an
optimal control framework. The predictive reservoir operation method provides optimal time operation of
flood control system with incorporation of current and predicted flood wave. The model utilizes a
dynamic programming with successive algorithm, interacting with hydrologic routing method.
From the developed optimization model connected with the hydrologic routing model analyses of a
number of predicted flood waves of Tigris river released from Mosul dam, Greater Zab and Dokan dam
on the Lesser Zab have been accomplished. It was concluded that the optimal maximum operation water
level in the reservoir of proposed Alfatha dam realized that all the hydraulic topographic and design
constraints were 164 m.a.s.l. for the two depended predicted operation scenarios of the reservoir. While a
maximum water level of 165 m.a.s.l. is the optimal operation level for the worst operation scenario of the
reservoir. This operation scenario is recommended in the future hydraulic design of the Alfatha dam.
Earthmoving is the process of moving and processing soil from one location to another to alter an existing land surface into a desired configuration. Highways, dams, and airports are typical examples of heavy earthmoving projects. Over the years, con
struction managers have devised ways to determine the quantities of material to be moved from one place to another. Various types of soil (soft earth, sand, hard clay, …, etc.) create different level of difficulty of the problem. Earthmoving problem has traditionally been solved using mass diagram method or variety of operational research techniques. However, existing models do not present realistic solution for the problem. Multiple soil types are usually found in cut sections and specific types of soil are required in fill sections. Some soil types in cut sections are not suitable to be used in fill sections and must be disposed of. In this paper a new mathematical programming model is developed to find-out the optimum allocation of earthmoving works. In developing the proposed model, different soil types are considered as well as variation of unit cost with earth quantities moved. Suggested borrow pits and/or disposal sites are introduced to minimize the overall earthmoving cost. The proposed model is entirely formulated using the programming capabilities of VB6 while LINDO is used to solve the formulated model to get the optimum solution. An example project is presented to show how the developed model can be implemented.
This research deals with the minimum cost design of reinforced concrete T-beams
according to the Syrian code. The aim is to minimize the total cost of the beam while
respecting all the design requirements. Traditional method depend on a set of supp
ositions,
in the opposite this methodology aim to reach the optimal solution among a set of
constraints with respect the objective function. So that, using this methodology leading to
the minimum cost reinforced section design.
This research is shown that the problem can be formulated in a nonlinear
mathematical programming format.
Several cases are used to explain the applicability of the formulation in accordance
with the current Syrian code. Traditional method of Syrian code has been used to design
sections in this paper, utilizing the nonlinear programming method provided by Lingo14.0
software from LINDO Systems Inc. The comparison of the results shows that important
saving can be obtained at the total cost of a reinforced concrete T-beams design.
