Search results
1 – 5 of 5Hamed Pourazad, Javad Askari and Saeed Hosseinnia
Increasing commercial applications for small unmanned aircraft create growing challenges in providing safe flight conditions. The conventional measures to detect icing are either…
Abstract
Purpose
Increasing commercial applications for small unmanned aircraft create growing challenges in providing safe flight conditions. The conventional measures to detect icing are either expensive, energy consuming or heavy. The purpose of this paper is to develop a fault identification and isolation scheme using unknown input observers to detect and isolate actuator and structural faults in simultaneous occurrence.
Design/methodology/approach
The fault detection scheme is based on a deviation in system parameters due to icing and lock-in-place (LIP), two faults from different categories with similar indications that require different reconfiguration actions. The obtained residual signals are selected to be triggered by desired faults, while insensitive to others.
Findings
The proposed observer is sensitive to both actuator and structural faults, and distinguishes simultaneous occurrences by insensitivity to LIP in selected residue signals. Simulation results confirm the success of the proposed system in the presence of uncertainty and disturbance.
Research limitations/implications
The fault detection and isolation scheme proposed here is based on the linear model of a winged aircraft, the Aerosonde. Moreover, the faults are applied to rudder and aileron in simulations, but the design procedure for other models is provided. The designed scheme could be further implemented on a non-linear aircraft model.
Practical implications
Applying the proposed icing detection scheme increases detection system reliability, since fault isolation enables timely reconfiguration schemes.
Originality/value
The observers proposed in previous papers detected icing fault but were not insensitive to actuator faults.
Details
Keywords
Hassan Abdolrezaei, Hassan Siahkali and Javad Olamaei
This paper aims to present a hybrid model to mid-term forecast the load of transmission substations based on the knowledge of expert site and multi-objective posterior framework…
Abstract
Purpose
This paper aims to present a hybrid model to mid-term forecast the load of transmission substations based on the knowledge of expert site and multi-objective posterior framework. The main important challenges in load forecasting are the different behavior of load in specific days. Regular days, holidays and special holidays, days after a holidays and days of load shifting are characterized by abnormal load profiles. The knowledge of these days is verified by expert operators in regional dispatching centers.
Design/methodology/approach
In this paper, a hybrid model for power prediction of transmission substations based on the combination of similar day selection and multi-objective posterior technique has been proposed. In the first step, the important data for prediction is provided. Posterior method is used in the second step for prediction that it is based on kernel functions. A multi-objective optimization has been formulated with three type of output accuracy measurement function that it is solved by non-dominated sorting genetic technique II (NSGT-II) method. TOPSIS way is used to find the best point of Pareto.
Findings
The presented method has been tested in four scenarios for three different transmission stations, and the test results have been compared. The presented results indicate that the presentation method has better results and is robust to different load characteristics, which can be used for better forecasting of different stations for better planning of repairs and network operation.
Originality/value
The main contributions of this paper can be categorized as follows: A hybrid model based on similar days selection and multi-objective framework posterior is presented. Similar day selection is done by expert site that the day type and days with scheduled repair are considered. Hyperparameters of posterior process are found by NSGT-II based on TOPSIS method.
Details
Keywords
Zeinab Sadri, Fereshteh Najafi, Reza Beiranvand, Farhad Vahid and Javad Harooni
While several studies have reported a relationship between chronic daily headache (CDH) and different dietary patterns, no study has investigated the association between CDH and…
Abstract
Purpose
While several studies have reported a relationship between chronic daily headache (CDH) and different dietary patterns, no study has investigated the association between CDH and the dietary inflammatory index (DII). This study aims to hypothesize that a higher DII score (proinflammatory diets) is associated with higher odds of CDH.
Design/methodology/approach
This cross-sectional study was performed using the baseline data of the Dena PERSIAN cohort study, including demographic information, body mass index, medical history, laboratory tests, sleep duration and blood pressure. The DII was computed based on the data collected by a valid 113-item food frequency questionnaire and a 127-item indigenous food questionnaire. The association between CDH and DII score was analyzed by simple and multiple logistic regression.
Findings
Out of 3,626 people included in the study, 23.1% had CDH. The median DII was −0.08 (interquartile range = 0.18). People in the third and fourth quartiles of DII (proinflammatory diet) had a 20% (odds ratio: 0.80; 95% confidence interval: 0.65–1) and a 25% (odds ratio: 0.75; 95% confidence interval: 0.61–0.94) lower chance of having CHD than those in the first quartile, respectively. After adjustment for confounding variables, this association did not remain statistically significant (p > 0.05).
Originality/value
Although the analysis conducted without adjustment for medical history showed a significant association between proinflammatory diet and reduced CDH, considering the diverse etiology of different types of headaches and the paucity of studies in this area, further studies are needed to investigate the DII score of patients by the type of headache, its severity and duration.
Details
Keywords
Mohsen Nazarzadeh Zare, Javad Pourkarimi, Gholamreza Zaker Salehi and Sahba Rezaeian
The purpose of this paper is to examine faculty members’ views about the assessment of world-class university components in Iran’s comprehensive universities.
Abstract
Purpose
The purpose of this paper is to examine faculty members’ views about the assessment of world-class university components in Iran’s comprehensive universities.
Design/methodology/approach
This study adopted a descriptive methodology by using a survey method. The statistical population consisted of 8,548 faculty members of comprehensive universities all over Iran. Considering the large size of the population, the comprehensive universities were categorized into five clusters (North, South, East, West and Center). The authors selected the faculty members from different clusters using Cochran’s formula. A total of 367 faculty members were selected from five clusters. For data gathering, a researcher-designed questionnaire was used. In data analysis, statistical procedures including the Confirmatory Factor Analysis, Kolmogrov-Smirnov test, one-sample t-test, and Friedman test were performed.
Findings
The findings of the research showed that except for academic freedom, other components of world-class university in Iran’s comprehensive universities were lower than the mean.
Practical implications
The case study showed how Iran’s comprehensive universities can become world-class universities. The methods of this case study can also be used in other fields.
Originality/value
This study adds to the knowledge of a world-class universities. Therefore to reach a desired level in comprehensive universities’ preparation for converting to a world-class university, it is essential that the policy makers and organizers of Iran’s higher education system pay greater attention to items such as research motivation, research innovation, research budget increase, authority reduction on various university departments, internet bandwidth increase and laboratory facilities increase.
Details
Keywords
Mohsen Pakdaman, Sara Geravandi, Ali Hejazi, Mobin Salehi and Mahboobeh Davoodifar
Currently, the health system is a treatment-oriented system focused on service providers. In this system, the main focus is on the health market, with little attention on insured…
Abstract
Purpose
Currently, the health system is a treatment-oriented system focused on service providers. In this system, the main focus is on the health market, with little attention on insured. One way to get out of existing conditions is to empower the insured in order to involve them actively in maintaining and improving health. The paper aims to discuss these issues.
Design/methodology/approach
This qualitative study was done using the content analysis method. Based on the purposive sampling method and theoretical saturation criterion, 24 individuals including 12 health insurance experts and 12 insured participated in the study in 2018. The semi-structured interview method was used to collect data. Data were analyzed using MAXQDA10 software.
Findings
Having analyzed the interviews, 750 codes were obtained. These codes were categorized into two categories of “insurance experts” and “insured” and ten subcategories of “informing and educating, cost reduction, intersectional activities, expectations from the insured, services package, access to services, inability to pay costs, participation, and expectations from the insurance organization.”
Originality/value
This qualitative study was conducted to assess and determine the effective strategies for empowering the insured under health insurance. The results of this study are helpful to the health insurance organizations and health decision makers to detect the effective ways to develop the quality of insurance services, improve the status of insured, and increase access to health care goods and services.
Details