Stochastic Multi-objective Short-term Hydro-thermal Self-scheduling in Joint Energy and Reserve Markets Considering Wind-Photovoltaic Uncertainty and Small Hydro Units

Behnamfar Mohammad Reza,Barati Hassan,Karami Mahdi 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

In this paper, a stochastic multi-objective structure is introduced in joint energy and reserve market to allow energy generation companies (GENCOs) participating in the short-term hydro-thermal self-scheduling with wind, photovoltaic uncertainty and small-hydro units. In addition, uncertainties including energy price, spinning and non-spinning reserve prices as well as the uncertainty of renewable energy resources such as output power of the wind, PV and small-hydro power plants are mentioned. One pivotal feature of this study is that two methods are used to generate stochastic multi-objective scenarios, namely lattice monte carlo simulation and roulette wheel mechanism. After that, the main purpose of the study is described, i.e., making GENCOs able to achieve the maximum profi t and the minimum emission by using a multi-objective function considering a stochastic process. To reach this aim, the mixed integer programming which includes a set of multi stage deterministic scenarios is employed. However, some special cases should be introduced in the formulation structure of the presented scheduling regarding hydro-thermal units to make the SMO-HTSS problem with wind, PV and SH units alike real time modeling. Since optimal Pareto solutions are produced in this method, one can allude to the application of the ε -constraint method. Nevertheless, in order to select one of the most appropriate solutions among Pareto solutions obtained, the utilization of fuzzy method has been presented. In the end, some tests are carried out on an IEEE 118-bus test system to verify the accuracy and validity of the proposed method.

Factors Associated with Delayed Diagnosis of Cervical Cancer in Iran - a Survey in Isfahan City

Behnamfar, Fariba,Azadehrah, Mahboobeh Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: In the absence of routine screening program for cervical cancer in Iran and high rate of diagnosed cancer in its advanced stage, recognition of sociodemographic factors related to delayed diagnosis of cancer in Iran could be helpful in reducing the burden of disease in our community. The aim of this study was to determine the stage of cervical cancer at diagnosis and factors related to delayed diagnosis of cervical cancer in Isfahan, Iran. Materials and Methods: In this cross sectional study women diagnosed with cervical cancer for the first time by histo-pathological examination were enrolled. According to the clinical and paraclinical findings and staging of the cancer, they were classified into early and delayed diagnosis of cervical cancer. Sociodemographic factors were compared in the two groups. Results: In this study of 55 women mean age was $48.3{\pm}12.0.$ According to our classification 6/55 (10.9%) and 49/55 (89.1%) of them had early and delayed diagnosis of cervical cancer. Delayed diagnosis of the cancer was significantly higher in patients with lower degree of education, lower socioeconomic status, having smoker and addict husband and those who did not have a history of Pap smear test (p<0.05). Conclusions: The results of this study indicated risk factors related to delayed diagnosis of cervical cancer. The affected women should be targeted for implementation of specialized educational programmes for improving knowledge and screening test.

Nonlinear analysis of stability of rock wedges in the abutments of an arch dam due to seismic loading

Mostafaei, Hasan,Behnamfar, Farhad,Alembagheri, Mohammad Techno-Press 2020 Structural monitoring and maintenance Vol.7 No.4

Investigation of the stability of arch dam abutments is one of the most important aspects in the analysis of this type of dams. To this end, the Bakhtiari dam, a doubly curved arch dam having six wedges at each of its abutments, is selected. The seismic safety of dam abutments is studied through time history analysis using the design-based earthquake (DBE) and maximum credible earthquake (MCE) hazard levels. Londe limit equilibrium method is used to calculate the stability of wedges in abutments. The thrust forces are obtained using ABAQUS, and stability of wedges is calculated using the code written within MATLAB. Effects of foundation flexibility, grout curtain performance, vertical component of earthquake, nonlinear behavior of materials, and geometrical nonlinearity on the safety factor of the abutments are scrutinized. The results show that the grout curtain performance is the main affecting factor on the stability of the abutments, while nonlinear behavior of the materials is the least affecting factor amongst others. Also, it is resulted that increasing number of the contraction joints can improve the seismic stability of dam. A cap is observed on the number of joints, above which the safety factor does not change incredibly.

Experimental Studies on a Combined Damper for Repairable Steel Moment Connections

Reza Soltanabadi,Farhad Behnamfar 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.1

Steel structures are among the building systems extensively used in most countries. They have been the subject of numerous studies with the aim of optimizing their performance under vertical and lateral loads. One important issue in this regard is reparability of connection areas under severe earthquakes, i.e., developing connections easy to be restored to their initial state. In this paper a passive control system recently developed by the authors is studied further and enhanced in configuration and behavior. The developed system is a repairable part of the connection zone in a steel moment frame absorbing the seismic damage and producing hysteretic damping. This damper is a rubber-steel core added beneath the beam-to-column connection. The steel bolts core provide for the hysteretic damping and the rubber layer contributes the restoring force. Results of several cyclic tests by varying different parameters of the damper are presented and discussed in this paper.

New Moment-Rotation Equation for Welded Steel Beam-to-Column Connections

Ehsan Soleimani,Farhad Behnamfar 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.2

A three-parameter tangent inverse equation is generically proposed for the non-linear moment-rotation (M-θ ) relationship of semi-rigid steel beam-to-column connections. The parameters are the initial stiffness, the plastic stiffness, and a reference moment. Two commonly used welded moment connections are picked up for moment-rotation calculation and comparison between the results of the proposed model and those of a detailed nonlinear finite elements modeling. Semi-analytical equations are proposed for calculating the parameters containing basic factors affecting behavior of the connections. The coefficients of the equations are computed based on a data bank developed in this study using the finite element method. A large number of finite elements models covering the whole range of common dimensions of the above connections are analyzed. Accuracy of the finite element model is verified on the basis of the available test results from previous studies. Tensile tests for determination of material properties of weld to be used in the modeling are conducted. Comparison between the results of the semi-analytical equations and the finite element models shows that the proposed model is able to estimate the moment-rotation curves of the welded beam-to-column connections with very good accuracy.

Introducing the Innovative Post-tensioned Connection with the Rigid Steel Node

Ali Jahangiri,Farhad Behnamfar,Mohammad Jahangiri 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

Securing strength, stiffness, and ductility in connections is one of the most important goals in structural design. After the Northridge earthquake, most steel moment resistant frames were damaged due to sudden fractures in beam-to-column connections. This resulted in the reconsideration of connection design and performance. As an alternative to weld connections, some researchers proposed the implementation of post-tensioned connections. In the present paper, the innovative connection is a combination of high strength steel frames which, through a rigid steel node above and below the beam flanges, provide the required stiffness, strength and ductility. Advantages of this connection include self-centering capability, lack of residual deformations, and energy dissipation which are analyzed using numerical and experimental methods. The modeling procedure and the cyclic behavior of the connection are studied and the analytical and the experimental results are compared. The results show that the cyclic responses observed in numerical simulations are in agreement with those from the experimental task and that the connection is superior to conventional moment resisting connections. The assumptions employed in simplifying simulations demonstrated high accuracy revealing an improvement in the seismic behavior of the connection.