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Showing 5 results for Mohammadi
Mohammadi Limaei, Lohmander, Obersteiner,
Volume 2, Issue 1 (vol 2. No 1 2010)
Abstract
The optimal harvesting policy is calculated as a function of the entering stock, the price state, the harvesting cost, and the rate of interest in the capital market. In order to determine the optimal harvest schedule, the growth function and stumpage price process are estimated for the Swedish mixed species forests. The stumpage price is assumed to follow a stochastic Markov process. A stochastic dynamic programming technique and traditional deterministic methods are used to obtain the optimal decisions. The expected present value of all future profits is maximized. The results of adaptive optimization are compared with results obtained by the traditional deterministic approach. The results show a significant increase in the expected economic values via optimal adaptive decisions.
Dr. S Mohammadi Limaei, Dr. Peter Lohmander,
Volume 8, Issue 1 (4-2017)
Abstract
We present a stochastic dynamic programming approach with Markov chains for optimal control of the forest sector. The forest is managed via continuous cover forestry and the complete system is sustainable. Forest industry production, logistic solutions and harvest levels are optimized based on the sequentially revealed states of the markets. Adaptive full system optimization is necessary for consistent results. The stochastic dynamic programming problem of the complete forest industry sector is solved. The raw material stock levels and the product prices are state variables. In each state and at each stage, a quadratic programming profit maximization problem is solved, as a subproblem within the STDP algorithm.
Dr. Bijan Mohammadi,
Volume 10, Issue 2 (9-2019)
Abstract
This contribution gathers some of the ingredients presented during the Iranian Operational Research community gathering in Babolsar in 2019.It is a collection of several previous publications on how to set up an uncertainty quantification (UQ) cascade with ingredients of growing computational complexity for both forward and reverse uncertainty propagation.
Amir-Mohammad Golmohammadi, Hamidreza Abedsoltan,
Volume 14, Issue 2 (12-2023)
Abstract
Enhancing the efficacy and productivity of transportation system has been on the most common issues in recent decades, noteworthy to the industrial managers and expert so that the products are delivered to the clients at right time and the least costs. Therefore, there are two important issues; one is to create hub as the as intermediaries for streaming from multiple origins to multiple destinations and also responding to the tours of every hub at the proper time. The other is a route where the vehicles should pay at time window of each destination node. On the other hand, these problems may cause cost differences between hub and interruption of their balance. Accordingly, this paper presents a model dealing with cost balancing among the vehicles as well as reducing the total cost of the system. Given the multi-objective and NP-Hard nature of the issue, a multi-objective imperialist competitive algorithm (MOICA) is suggested to provide Pareto solutions. The provided solutions are at small, average and large scales are compared with the solutions provided by Non-Dominated Sorting Genetic Algorithm (NSGA-II) algorithm. Then, its performance is determined using the index for evaluating the algorithm performance efficacy to solve the problem at large dimensions.
Dr Shabnam Mohammadi Ardakani, Dr Hamid Babaei Meybodi,
Volume 15, Issue 2 (12-2024)
Abstract
With the expansion of emerging technologies, their applications have been introduced as a transformative factor in many industries and fields. However, these developments require more research in the area of new technologies. Nevertheless, few studies have comprehensively examined the published research in this field. In this regard, bibliometric studies, as one of the effective research methods in the field of emerging technologies, are a practical and effective tool in identifying research patterns, knowledge flows, study content, and key terms. Using this method, one can understand and briefly examine the scientific foundations and impact of emerging technologies. In summary, conducting bibliometrics in the field of emerging technologies can be used as an effective tool in identifying and analyzing research paths and the development of advanced technologies. In this context, articles published in the field of emerging technologies in the period 2013-2023 in various fields have been examined. The required data includes 13,263 articles extracted from the WOS database and were analyzed using Biblioshiny software under R-package. The obtained results include identifying influential authors, leading journals, organizations, and countries related to the field of emerging technologies. Additionally, using precise bibliometric analysis tools, the authors' collaboration network, thematic trends, most common terms, and citation network have been extracted. Finally, with the help of network analysis, key clusters in the existing literature have been identified based on research areas of new technologies.
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