Mehdi Dehghani, Mahdi Ahmadi, Alireza Khayatian, Mohamad Eghtesad and Mehran Yazdi
The purpose of this paper is to present a vision-based method for the kinematic calibration of a six-degrees-of-freedom parallel robot named Hexa using only one Universal Serial…
Abstract
Purpose
The purpose of this paper is to present a vision-based method for the kinematic calibration of a six-degrees-of-freedom parallel robot named Hexa using only one Universal Serial Bus (USB) camera and a chess pattern installed on the robot's mobile platform. Such an approach avoids using any internal sensors or complex three-dimensional measurement systems to obtain the pose (position/orientation) of the robot's end-effector or the joint coordinates.
Design/methodology/approach
The setup of the proposed method is very simple; only one USB camera connected to a laptop computer is needed and no contact with the robot is necessary during the calibration procedure. For camera modeling, a pinhole model is used; it is then modified by considering some distortion coefficients. Intrinsic and extrinsic parameters and the distortion coefficients are found by an offline minimization algorithm. The chess pattern makes image corner detection very straightforward; this detection leads to finding the camera and then the kinematic parameters. To carry out the calibration procedure, several trajectories are run (the results of two of them are presented here) and sufficient specifications of the poses (positions/orientations) are calculated to find the kinematic parameters of the robot. Experimental results obtained when applying the calibration procedure on a Hexa parallel robot show that vision-based kinematic calibration yields enhanced and efficient positioning accuracy. After successful calibration and addition of an appropriate control scheme, the robot has been considered as a color-painting prototype robot to serve in relevant industries.
Findings
Experimental results obtained when applying the calibration procedure on a Hexa parallel robot show that vision-based kinematic calibration yields enhanced and efficient positioning accuracy.
Originality/value
The enhanced results show the advantages of this method in comparison with the previous calibration methods.
Details
Keywords
Madjid Tavana, Amir Karbassi Yazdi, Mehran Shiri and Jack Rappaport
This paper aims to propose a new benchmarking framework that uses a series of existing intuitive and analytical methods to systematically capture both objective data and…
Abstract
Purpose
This paper aims to propose a new benchmarking framework that uses a series of existing intuitive and analytical methods to systematically capture both objective data and subjective beliefs and preferences from a group of decision makers (DMs).
Design/methodology/approach
The proposed framework combines the excellence model developed by the European Foundation for Quality Management with the Rembrandt method, the entropy concept, the weighted‐sum approach, and the theory of the displaced ideal. Hard data and personal judgments are synthesized to evaluate a set of business units (BUs) with two overall performance scores plotted in a four quadrant model.
Findings
The two performance scores are used to benchmark the performance of the BUs in accordance with their Euclidean distance from the “ideal” BU. Quadrants are used to classify the BUs as efficacious, productive ineffectual, proficient unproductive, and inefficacious. The efficacious BUs, referred to as “excellent”, fall in the competency zone and have the shortest Euclidean distance from the ideal BU relative to their peers.
Originality/value
The benchmarking framework presented in this study has some obvious attractive features. First, the generic nature of the framework allows for the subjective and objective evaluation of a finite number of BUs by a group of DMs. Second, the information requirements of the framework are stratified hierarchically allowing DMs to focus on a small area of the large problem. Third, the framework does not dispel subjectivity; it calibrates the subjective weights with the objective weights determined through the entropy concept.
Details
Keywords
Dechao Sun, Tahir Mahmood, Ubaid ur Rehman and Shouzhen Zeng
Gathering, analyzing and securing electronic data from various digital devices for use in legal or investigative procedures is the key process of computer forensics. Information…
Abstract
Purpose
Gathering, analyzing and securing electronic data from various digital devices for use in legal or investigative procedures is the key process of computer forensics. Information retrieved from servers, hard drives, cellphones, tablets and other devices is all included in this. This article tackles the challenging problem of how to prioritize different kinds of computer forensics and figure out which kind is most useful in cases of cybercrime, fraud, theft of intellectual property, harassment and espionage.
Design/methodology/approach
Therefore, we first introduce enhanced versions of Hamacher power aggregation operators (AOs) within the framework of bipolar complex fuzzy (BCF) sets. These include BCF Hamacher power averaging (BCFHPA), BCF Hamacher power-weighted averaging (BCFHPWA), BCF Hamacher power-ordered weighted averaging (BCFHPOWA), BCF Hamacher power geometric (BCFHPG), BCF Hamacher power-weighted geometric (BCFHPWG) and BCF Hamacher power-ordered-weighted geometric (BCFHPOWG) operators. Employing the devised AOs, we devise a technique of decision-making (DM) for dealing with DM dilemmas with the BCF set (BCFS).
Findings
We prioritize different types of computer forensic by taking artificial data in a numerical example and getting the finest computer forensic. Further, by this example, we reveal the applicability of the proposed theory. This work provides a more elaborate and versatile procedure for classifying computer forensics with dual aspects of criteria and extra fuzzy information. It allows for better and less biased DM in the more intricate digital investigations, which may lead to better DM and time-saving in real-life forensic scenarios. To demonstrate the significance and impression of the devised operators and techniques of DM, they are compared with existing ones.
Originality/value
This research is the first to combine Hamacher and power AOs in BCFS for computer forensics DM. It presents new operators and a DM approach that is not encountered in the existing literature and is specifically designed to deal with the challenges and risks associated with the classification of computer forensics. The framework’s capacity to accommodate bipolar criteria and extra fuzzy information is a major development in the field of digital forensics and decision science.
Details
Keywords
Zamzam Paknahad, Leila Yazdanpanah, Mohammad Reza Maracy, Amir Reza Moravejolahkami, Seyed Ali Javad-Mousavi and Abbas Nemati
Patients with chronic obstructive pulmonary disease (COPD) suffer from many health problems including poor sleep. This paper aims to evaluate the relationship between diet quality…
Abstract
Purpose
Patients with chronic obstructive pulmonary disease (COPD) suffer from many health problems including poor sleep. This paper aims to evaluate the relationship between diet quality indices (DQIs) and sleep quality in COPD.
Design/methodology/approach
The current cross-sectional study was carried on 121 COPD patients. Subjective quality of sleep was determined by Pittsburgh Sleep Quality Index (PSQI) and categorized into “poor” and “good” sleep quality. Dietary history was assessed by the DQIs. Disease status was categorized according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Guidelines.
Findings
In total, 103 men and 18 women with a mean age of 66.1 ±10.9 were studied. The subjects were categorized into four groups based on GOLD; 3.3% of subjects were at Stage 1, 38% in Stage 2, 38% in Stage 3 and 20.7% in Stage 4. In total, 38% of subjects were good, and 62% were bad sleepers according to PSQI score. There was no significant relationship between the severity of COPD and PSQI score. We observed a significant inverse relation between PSQI total score and Mediterranean diet (MED) scale, Healthy Eating Index (HEI)-2010 and HEI-2005 (p = 0.024, 0.037 and 0.024, respectively) in males.
Originality/value
This study showed a high prevalence of poor quality of sleep and sleep disturbances among COPD patients. There was an inverse association between PSQI and sleep disorders and DQIs scores in COPD patients. Regardless of the severity of airflow obstruction, poor diet quality may constitute a risk factor for sleep quality.