Fuzzy Greedy RRT Path Planning Algorithm in a Complex Configuration Space

Ehsan Taheri,Mohammad Hossein Ferdowsi,Mohammad Danesh 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

A randomized sampling-based path planning algorithm for holonomic mobile robots in complex configuration spaces is proposed in this article. A complex configuration space for path planning algorithms may cause different environmental constraints including the convex/concave obstacles, narrow passages, maze-like spaces andcluttered obstacles. The number of vertices and edges of a search tree for path planning in these configuration spaces would increase through the conventional randomized sampling-based algorithm leading to exacerbation of computational complexity and required runtime. The proposed path planning algorithm is named fuzzy greedy rapidly-exploring random tree (FG-RRT). The FG-RRT is equipped with a fuzzy inference system (FIS) consisting of two inputs, one output and nine rules. The first input is a Euclidean function applied in evaluating the quantityof selected parent vertex. The second input is a metaheuristic function applied in evaluating the quality of selected parent vertex. The output indicates the competency of the selected parent vertex for generating a random offspringvertex. This algorithm controls the tree edges growth direction and density in different places of the configuration space concurrently. The proposed method is implemented on a Single Board Computer (SBC) through the xPC Target to evaluate this algorithm. For this purpose four test-cases are designed with different complexity. The results of the Processor-in-the-Loop (PIL) tests indicate that FG-RRT algorithm reduces the required runtime and computational complexity in comparison with the conventional and greedy RRT through fewer number of vertices in planning an initial path in significant manner.

Multi-project Time-cost Optimization in Critical Chain with Resource Constraints

Mohammad Javad Taheri Amiri,FarshidReza Haghighi,Ehsan Eshtehardian,Ozeair Abessi 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

The simultaneous reduction of the project cost and time has paramount importance in today's competitive world; however, it is necessary to balance the project time and cost because of the reduction asymmetry of the two factors in a project. How to balance the cost and time parameters in managing construction projects is also critical and there have always been some attempts made to provide different approaches to control it. Given the immense importance of considering resource constraints for project scheduling problems, and the proximity of the study conditions to the real world, resource constraints were also included. In a project, project managers need to be aware of resource constraints. As resource constraint scheduling problem is considered NP-hard, the metaheuristic models were developed in this paper in order to obtain results contributing to project managers’ decision-making. For this purpose, a non-dominated sorting genetic algorithm method was developed to optimize a time-cost trade-off problem. Furthermore, to solve a multi-project scheduling problem, the critical chain method was used. In order to evaluate the performance of the model, the developed model was first studied in a small scale and then simultaneous projects with 7, 8 and 10 tasks were planned. Because resource availability is essential in such problems, after solving the proposed model, a sensitivity analysis was performed for daily resources and the results were discussed. Results shows the ability of the proposed model and methodology to optimize the time-cost tradeoff considering resource constraints in sample problems. Solutions obtained showed that in some cases of scheduling without this algorithm, resource consumption exceeded above resource availability. After solving the model by proposed algorithm, resource allocation is implemented considering resource constraint. This model determined these resources as crucial and helped managers to control them.

Fabrication and Dielectric Properties of Pb(Zr0.52Ti0.48)O3 Nanofibers-Cement Composites

Mohammad Khajelakzay,Ehsan Taheri-Nassaj 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

In this study, the Pb(Zr0.52Ti0.48)O3 nanofibers-cement composites were fabricated and their dielectric properties were measured. First, lead zirconate titanate (Pb(Zr0.52Ti0.48)O3) nanofibers were synthesized using electrospinning method. Then, the Pb(Zr0.52Ti0.48)O3 nanofibers-cement composites were obtained by pressing the mixture of white cement and the Pb(Zr0.52Ti0.48)O3 nanofibers under a high pressure followed by steam curing. For the composite with 90 vol. %Pb(Zr0.52Ti0.48)O3 nonafibers, the values of εr and tanδ in 1 kHz frequency were obtained to be 777 and 0.067, respectively.

Anti-Toxoplasma Effects of Methanol Extracts of Feijoa sellowiana, Quercus castaneifolia, and Allium paradoxum

Ebrahimzadeh, Mohammad Ali,Taheri, Mohammad Mohammad,Ahmadpour, Ehsan,Montazeri, Mahbobeh,Sarvi, Shahabeddin,Akbari, Mohammad,Daryani, Ahmad KOREAN PHARMACOPUNCTURE INSTITUTE 2017 Journal of pharmacopuncture Vol.20 No.3

Objectives: The currently available agents for use against toxoplasmosis have serious limitations. Thus, the aim of the present study was to investigate the anti-Toxoplasma gondii (T. gondii) activities of methanol extracts of Feijoa sellowiana (F. sellowiana) (leaves and fruits), Quercus castaneifolia (Q. castaneifolia) (fruits), and Allium paradoxum (A. paradoxum) (leaves) in vitro and in vivo. Methods: Vero cells were treated with different concentrations (from 0 to $400{\mu}g/mL$) of the above extracts or with pyrimethamine at a dose of 50 mg/mL (positive control). Then, the viabilities of the T. gondii-infected cells were measured by using colorimetric MTT (3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide) assays. In addition, the survival rates of mice acutely infected with $2{\times}10^4$ RH strain tachyzoites of T. gondii were examined in vivo after intraperitoneal injection of the extracts at doses of 100 and 200 mg/kg/day for 5 days. Results: In the in vitro anti- T. gondii assay, the $IC_{50}$ values were 12.77, 180.2, 74.73, 213.2 and $163.8{\mu}g/mL$, and the selectivity indices were 6.05, 1.31, 0.35, 0.69 and 1.30 for the F. sellowiana (leaves and fruits), Q. castaneifolia, and A. paradoxum extracts and pyrimethamine, respectively. Moreover, the mice treated with F. sellowiana (leaves and fruits) achieved better results in terms of survival than the others (P < 0.05). Conclusion: The results of the current study indicate that methanol extract of F. sellowiana has significant anti-Toxoplasma activity. Further study should be conducted to investigate the potential bioactivity of this extract through bioactivity-guided fractionation.

Synthesis and characterization of alumina supported sub-nanoporous SiO2–10 wt%TiO2 membrane for nitrogen separation

Yaghoob Farhang-Ghoje Biglu,Ehsan Taheri-Nassaj 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

Membrane of SiO2–10TiO2 was produced by dip coating on mesoporous-titania-coated macroporous alumina support. The amorphous SiO2–10TiO2 top layer with thickness of 0.9 mm was obtained as a homogenous and defect free surface. Gas permeation tests show a decrease in permeation in order of CH4 > N2 for the support, and N2 > CH4 for the multilayer membrane. The membrane delivering promised single gas separation factor for N2/CH4 (1.75). It was also observed that the membrane separation factor in binary gas mixture was 12–15% of the single gas separation factor, while the permeation revealed a decrease in gas mixture.

Anti-Toxoplasma Effects of Methanol Extracts of Feijoa sellowiana, Quercus castaneifolia, and Allium paradoxum

Mohammad Ali Ebrahimzadeh,Mohammad Mohammad Taheri,Ehsan Ahmadpour,Mahbobeh Montazeri,Shahabeddin Sarvi,Mohammad Akbari,Ahmad Daryani 대한약침학회 2017 Journal of pharmacopuncture Vol.20 No.3

Objectives: The currently available agents for use against toxoplasmosis have serious limitations. Thus, the aim of the present study was to investigate the anti-Toxoplasma gondii (T. gondii) activities of methanol extracts of Feijoa sellowiana (F. sellowiana) (leaves and fruits), Quercus castaneifolia (Q. castaneifolia) (fruits), and Allium paradoxum (A. paradoxum) (leaves) in vitro and in vivo. Methods: Vero cells were treated with different concentrations (from 0 to 400 μg/mL) of the above extracts or with pyrimethamine at a dose of 50 mg/mL (positive control). Then, the viabilities of the T. gondii-infected cells were measured by using colorimetric MTT (3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide) assays. In addition, the survival rates of mice acutely infected with 2 × 104 RH strain tachyzoites of T. gondii were examined in vivo after intraperitoneal injection of the extracts at doses of 100 and 200 mg/kg/day for 5 days. Results: In the in vitro anti- T. gondii assay, the IC50 values were 12.77, 180.2, 74.73, 213.2 and 163.8 μg/mL, and the selectivity indices were 6.05, 1.31, 0.35, 0.69 and 1.30 for the F. sellowiana (leaves and fruits), Q. castaneifolia, and A. paradoxum extracts and pyrimethamine, respectively. Moreover, the mice treated with F. sellowiana (leaves and fruits) achieved better results in terms of survival than the others (P < 0.05). Conclusion: The results of the current study indicate that methanol extract of F. sellowiana has significant anti-Toxoplasma activity. Further study should be conducted to investigate the potential bioactivity of this extract through bioactivity-guided fractionation.