OPTIMIZATION AND DESIGN OF DISK-TYPE MR BRAKES

B. ASSADSANGABI,F. DANESHMAND,N. VAHDATI,M. EGHTESAD,Y. BAZARGAN-LARI4 한국자동차공학회 2011 International journal of automotive technology Vol.12 No.6

In this paper, first a new design for a disk-type magneto-rheological (MR) brake for automotive applications is proposed and then, a finite element analysis is performed to analyze the resulting magnetic field intensity distribution within the MR brake configuration. This finite element model of the brake is then utilized in a optimization process which incorporates Genetic Algorithm (GA) to obtain optimal design parameters. The optimization process goal is to increase the braking torque capacity of the brake while keeping the weight of the brake as low as possible. Although, the braking torque of the present design is larger compared to the previous designs, the braking toque capacity of the present design is still smaller than the required braking torque for automobiles.

Will Rogers and the Politics of Multi-Cultural America: A Critique of Media Theory

( Lary L. May ) 한국아메리카학회 1991 美國學論集 Vol.23 No.1

Linguistic Meaning and Use in the Information Age

Lary D. Chong 國際言語文學會 2003 國際言語文學 Vol.- No.7

Multi-camera System Calibration with Built-in Relative Orientation Constraints (Part 2) Automation, Implementation, and Experimental Results

Lari, Zahra,Habib, Ayman,Mazaheri, Mehdi,Al-Durgham, Kaleel 한국측량학회 2014 한국측량학회지 Vol.32 No.3

Characterization of Effective Capacity in Antenna Selection MIMO Systems

Lari, Mohammad,Mohammadi, Abbas,Abdipour, Abdolali,Lee, Inkyu The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.5

In this paper, the effective capacity of a multiple-input multiple-output (MIMO) system in two different cases with receive antenna selection (RAS) and transmit antenna selection (TAS) schemes is investigated. A closed-form solution for the maximum constant arrival rate of this network with statistical delay quality of service (QoS) constraint is extracted in the quasi-static fading channel. This study is conducted in two different cases.When channel state information (CSI) is not available at the MIMO transmitter, implementation of TAS is difficult. Therefore, RAS scheme is employed and one antenna with the maximum instantaneous signal to noise ratio is chosen at the receiver. On the other hand, when CSI is available at the transmitter, TAS scheme is executed. In this case, one antenna is selected at the transmitter. Moreover, an optimal power-control policy is applied to the selected antenna and the effective capacity of the MIMO system is derived. Finally, this optimal power adaptation and the effective capacity are investigated in two asymptotic cases with the loose and strict QoS requirements. In particular, we show that in the TAS scheme with the loose QoS restriction, the effective capacity converges to the ergodic capacity. Then, an exact closed-form solution is obtained for the ergodic capacity of the channel here.

The relationship between audit quality and Investment efficiency

Mahmoud Lari Dashtbayaz,Shaban Mohammadi 국제융합경영학회 2016 융합경영연구 Vol.4 No.2

The purpose of the present study is to investigate the audit quality and Investment efficiency of the listed companies on the Tehran Stock Exchange (TSE). The population includes 94 firms selected through systematic sampling. The data is collected from the audited financial statements of the firms provided by TSE’s website from 2008 to 2015. In this study the variables, auditor industry specialization, auditor reputation, auditor tenure and auditor independence has been used to investigate audit quality. The results of multiple linear regression analysis show that there is a significant relationship audit quality and Investment efficiency.

An Evolutionary Approach to Design Practical µ Synthesis Controllers

Ali Lari,Alireza Khosravi 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.1

This paper proposes an evolutionary approach to solve µ synthesis problem. The goal is to achieve low order, practical µ synthesis controllers without any order reduction. In the proposed approach µ synthesis problem is solved as a constraint optimization problem in which robust stability and robust performance based on µ analysis are considered as the constraint and the cost function respectively. In order to solve the optimization problem an improved particle swarm optimization (PSO) is chosen to find the required coefficients of a structure-specified controller. The performance and robustness of the proposed controller are investigated by an uncertain mass-damper-spring system and is compared with the D-K iteration controller (the conventional solution to µ synthesis problem). Simulation results demonstrate the advantages of the proposed controller in terms of simple structure and robustness against plant perturbations and disturbances in comparison with D-K iteration controller.

Assessment of Geometrical Features of Internal Flaws with Artificial Neural Network

Salman Lari,Yanjun Qian,Hyock Ju Kwon 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.5

In nondestructive testing (NDT), geometrical features of a flaw embedded in the material such as its location, length, and orientation are critical factors to assess the severity of the flaw and make post-manufacturing decisions to improve the design. In this study, artificial intelligence (AI) based NDT approach was applied to the ultrasonic oscillograms obtained from virtual ultrasonic NDT to estimate geometrical features of a flaw. First, a numerical model of NDT specimen was constructed using acoustic finite element analysis (FEA) to produce the ultrasonic signals. The model was validated by comparing the simulated signals produced from the numerical model with the experimental data from actual NDT tests. Then, 750 numerical models containing flaws with different locations, lengths, and orientation angles were generated by FEA. Next, the oscillograms produced by the models were divided into 3 datasets: 525 for training, 113 for validation, and 112 for testing. Training inputs of the network were parameters extracted from ultrasonic signals by fitting them to sine functions. Lastly, to evaluate the network performance, outputs of the network including flaw’s location, length, and angle were compared with the desired values for all datasets. Deviations of the outputs from desired values were calculated by a regression analysis. Statistical analysis was also performed by measuring root mean square error (RMSE) and efficiency. RMSE in x-location, y-location, length, and angle estimations are 0.09 mm, 0.19 mm, 0.46 mm, and 0.75°, with efficiencies of 0.9229, 0.9466, 0.9140, and 0.9154, respectively for the testing dataset. Results suggest that the proposed AI-based method has the potential to interpret the oscillograms from ultrasonic NDT to estimate geometrical features of flaws embedded in the material.

Capital Market Development: Evidence from the Role of Audit

Mahmoud Lari Dashtbayaz,Shaban Mohammadi 국제융합경영학회 2015 융합경영연구 Vol.3 No.3

Quality auditor and auditors of larger firms have a positive effect on profit is unusual. The auditors smaller negative effect on profit companies profit is unusual. Change to larger audit shows the quality of earnings and to respond more investors positive changes in income and increased costs and reduced profitability is less negative price changes. Similarly, switching to a smaller auditor confirms the low quality of earnings, resulting in a negative response to the market. In this article market reaction (response investors) the quality of the audit and the auditor were studied in the Tehran Stock Exchange. in general, information about companies in capital market accounting to investors and the capital market is considered to be valuable.

The Impact of Management on the Operational Efficiency of Listed Companies in Tehran Stock Exchange

Mahmoud Lari Dashtbayaz,Shaban Mohammadi,Ali Shirzad 국제융합경영학회 2015 융합경영연구 Vol.3 No.4

This study examined the relationship between working capital management and performance of listed companies Stock Exchange in Tehran. A total of 40 companies from the cement industry for the period 2007 to 2010 of which only 25 were selected for this study had the condition. In order to achieve the objectives, this study surveys the exploration of correlation regression analysis and used the curve obtained, the regression equation. To test the hypothesis, quantitative analysis was used as a method. The results showed a negative relationship between the variables of working capital management and the company's performance and the only variable cash conversion cycle did not show a significant relationship. There is often a negative correlation between the variables studied. This study is based on five assumptions impact of working capital management on corporate profitability is examined. Therefore, the results suggest that the variables in working capital (average collection of receivables, average inventory turnover period, the average net debt and average transaction cycle) and net operating profit is significant negative correlation Net cash conversion cycle and only illustrates the relationship is not significant. Thus, it showed that in debt collection and debt payment period, the turnover of inventory and net trade cycle to reduce the profitability of companies will increase.