Showing 4 results for State
Mohsen Nourizadeh, Moharram Habibnejad Korayem, Hami Tourajizadeh,
Volume 0, Issue 0 (10-2024)
Abstract
The purpose of this paper is to optimal control a dual-stage cable robot in a predefined path and to determine the maximum load-carrying capacity of this robot as a tower crane. Also, to increase the workspace of the robot two stages are employed. Today, cable robots are extensively used in load handling. Positive cable tension and collision-free cable control are the most important challenges of this type of robot. The high ratio of transposable loads to weight makes these robots very attractive for use as tower cranes. Dynamic Load Carrying Capacity (DLCC) is the maximum load that can be carried along a predefined path without violating the actuators and allowable accuracy constraints. State-Dependent Riccati Equation (SDRE) is employed to control the end-effector within the path to achieve the maximum DLCC. This approach is chosen since it can optimize the required motors' torque which consequently leads us to the maximum DLCC. In addition, the constraint of cables’ collision together is also checked along the predetermined path using the non-interference algorithm. The correctness of modeling is verified by comparing the results with previous research and the efficiency of the proposed optimal controlling strategy toward increasing the DLCC is investigated by conducting some comparative simulations. It is shown that the proposed cable robot by the aid of the designed optimal controller can move the maximum load successfully along any desired path using the least amount of motors' torque.
J. Fathikalajahi, M. Baniadam , R. Rahimpour ,
Volume 19, Issue 3 (7-2008)
Abstract
An equation-oriented approach was developed for steady state flowsheeting of a commercial methanol plant. The loop consists of fixed bed reactor, flash separator, preheater, coolers, and compressor. For steady sate flowsheeting of the plant mathematical model of reactor and other units are needed. Reactor used in loop is a Lurgi type and its configuration is rather complex. Previously reactor and flash separator are modeled as two important units of plant. The model is based on mass and energy balances in each equipment and utilizing some auxiliary equations such as rate of reaction and thermodynamics model for activity coefficients of liquid. In order to validate the mathematical model for the synthesis loop, some simulation data were performed using operating conditions and characteristics of the commercial plant. The good agreement between the steady state simulation results and the plant data shows the validity of the model.
Nataliia Demchuk, Iuliia Masiuk2, Anastasiia Donskykh, Iryna Kadyrus,
Volume 31, Issue 4 (11-2020)
Abstract
The aim of the study is to develop theoretical and methodological foundations, scientific and practical recommendations for improving the management and evaluation of public debt in Ukraine. The methodological foundations of the study are a systematic approach to the analysis of the relationship of financial phenomena and processes, creative reflection on the works of Ukrainian and foreign scientists on public debt, and its role in the context of macro-financial stabilization. Specific scientific theoretical and applied developments by the applicant were obtained using the following methods: graphical financial analysis (for studying the tendencies of debt formation); statistical-economic (to identify the impact of public debt on socio-economic processes); economic-mathematical modeling (to determine the relationship between public debt and macroeconomic indicators). On the basis of the research, it was revealed that the selected macroeconomic indicators have a significant impact on the government debt, and there are difficulties in coordinating international, regional economic integration or creating a broad separation based on stable international competitiveness. In order to test the impact of some macroeconomic indicators on the size of public debt, the World Bank's economic indicators have been taken as the main material for research. The analyzed period of time is 2001-2017 years.
The recommendations provided in this article will contribute to the development of public debt management and the associated increase in the living standards of the country's population. Based on the analysis conducted, there are every reason to assert that effective management of public debt can contribute to the development of the national economy. The scientific novelty of the study is to determine the impact of some macroeconomic indicators on public debt management at the current stage of Ukraine's development.
Amirhossein Masoumi, Rouzbeh Ghousi, Ahmad Makui,
Volume 33, Issue 3 (9-2022)
Abstract
Purpose: Non-cancerous prostate lesions such as prostate calcification, prostate enlargement, and prostate inflammation cause too many problems for men’s health. This research proposes a novel approach, a combination of image processing techniques and deep learning methods for classification and segmentation of the prostate in CT-scan images by considering the experienced physicians’ reports.
Methodology: Due to the various symptoms and nature of these lesions, a three-phases innovative approach has been implemented. In the first phase, using Mask R-CNN, in the second phase, considering the age of each patient and comparison with the standard size of the prostate gland, and finally, using the morphology features, the presence of three common non-cancerous lesions in the prostate gland has investigated.
Findings: A hierarchical multitask approach is introduced and the final amount of classification, localization, and segmentation loss is 1%, 1%, and 7%, respectively. Eventually, the overall loss ratio of the model is about 9%.
Originality: In this study, a medical assistant approach is introduced to increase diagnosis process accuracy and reduce error using a real dataset of abdominal and pelvics’ CT scans and the physicians’ reports for each image. A multi-tasks convolutional neural network; also presented to perform localization, classification, and segmentation of the prostate gland in CT scans at the same time.
