24 research outputs found
Identification and ranking of effective factors of marketing (controllable) to receive the services from free zone with MADM approach
This study applies the fuzzy MCDM (multicriteria decision making) to evaluate the services Performance in free trade zone. Performance evaluation is an important issue for managers, since it can be used as a reference in decision making with regard to performance improvement, specially teaching performance improvement. For this purpose, in this study, we use fuzzy set theory for the measurement of performance and apply AHP in obtaining criteria weight and TOPSIS in ranking. A fuzzy MCDM is an approach for evaluating decision alternatives involving subjective judgments made by a group of decision makers. A pairwise comparison process is used to help individual decision makers make comparative judgments, and a linguistic rating method is used for making absolute judgments
Identification and ranking of effective factors of marketing (controllable) to receive the services from free zone with MADM approach
This study applies the fuzzy MCDM (multicriteria decision making) to evaluate the services Performance in free trade zone. Performance evaluation is an important issue for managers, since it can be used as a reference in decision making with regard to performance improvement, specially teaching performance improvement. For this purpose, in this study, we use fuzzy set theory for the measurement of performance and apply AHP in obtaining criteria weight and TOPSIS in ranking. A fuzzy MCDM is an approach for evaluating decision alternatives involving subjective judgments made by a group of decision makers. A pairwise comparison process is used to help individual decision makers make comparative judgments, and a linguistic rating method is used for making absolute judgments
Identification and ranking of effective factors of marketing (controllable) to receive the services from free zone with MADM approach
This study applies the fuzzy MCDM (multicriteria decision making) to evaluate the services Performance in free trade zone. Performance evaluation is an important issue for managers, since it can be used as a reference in decision making with regard to performance improvement, specially teaching performance improvement. For this purpose, in this study, we use fuzzy set theory for the measurement of performance and apply AHP in obtaining criteria weight and TOPSIS in ranking. A fuzzy MCDM is an approach for evaluating decision alternatives involving subjective judgments made by a group of decision makers. A pairwise comparison process is used to help individual decision makers make comparative judgments, and a linguistic rating method is used for making absolute judgments
Dynamic response of overhead transmission lines to ice shedding
The main objective of this research was to study dynamic effects of ice shedding on overhead transmission lines using a reliable numerical model.Overhead transmission lines are subjected to various static and dynamic loads. Ice shedding from the conductors is one of the dynamic loads occurring in cold regions. This phenomenon happens when glaze ice formed on the cables suddenly falls under certain temperature and wind conditions. In extreme instances, clashing and breakage of insulator and conductors are potential consequences of these dynamic forces. Maximum vertical cable jumps and drops in unloaded and loaded spans, and axial cable stresses are particular concerns.The main assumptions and limitations of the proposed numerical model are discussed in detail, with appropriate stiffness, mass, damping, and ice-shedding load modelling. A nonlinear finite-element model using a commercial software (ADINA) was used to carry out simulations of 21 different ice-shedding scenarios varying the number of successive spans involved, the amount of ice accreted on the cables, different elevations of the central support, partial and sub-span ice shedding and the configuration and sequence of the shedding in adjacent spans. The analysis of the results focuses on the peak cable tensions generated, the insulator string swings and the maximum transient in-span cable displacements. Some of the results are compared with the design procedures used at Hydro-Quebec, which is based on static analysis
Stress analysis of an optical ground wire
The main objective of this research was to create a finite element model for detailed three-dimensional stress analysis of an overhead optical ground wire (OPGW) typical of those used in transmission lines. The detailed model considers all possible mechanical effects, such as contact, friction, elongation, torsion, and bending for different end conditions.The OPGW under study comprises four components: the external layer of fourteen aluminum alloy wires and ten inner aluminum clad steel wires, which are laid over an aluminum tube that houses a five-groove aluminum spacer. The optical fiber units are inserted in the aluminum spacer grooves. Three-dimensional solid elements are used to model the outer wires, the inner wires, and the aluminum spacer. The central aluminum tube is modeled with shell elements with large strain and deformation kinematics. All possible contacts between the components, with and without friction, are considered in the model.The OPGW is assumed fixed at one end and pulled from the other with a prescribed displacement equivalent to the experimental elongation of 0.61% defined for all components.The finite element analysis predicts that the responses of the outer and inner wires are in the linear range, however the aluminum tube and spacer are yielded under the prescribed displacement. Therefore, a multilinear stress-strain law is used in the model.Two scenarios of loading were tested to apply the axial elongation on the wires; either only the central node or all the interior nodes of the wire cross sections are prescribed a maximum axial displacement.Results of the finite element model are compared with those of the experiments performed at IREQ and with the analytical solutions of Machida and Durelli (1973) and Phillips and Costello (1973). The calculated axial forces of the cable in the coarse and fine mesh models are 61% and 70% of those predicted by the analytical solutions, respectively. However, the differences in stresses and strains of the coarse mesh model are in the range of ten percent only from the theoretical solutions.The effective modulus of elasticity of the finite element model increases with tension. For the maximum elongation, the effective modulus obtained with the coarse and fine mesh models is 62% and 70% respectively of the equivalent modulus of elasticity calculated neglecting all three-dimensional effects.This study shows the reliability and significance of using finite element modeling in predicting the detailed response of a complex cable, for which experiments and theoretical solutions are unable to yield complete results. (Abstract shortened by UMI.
Fluid Intake Monitoring Systems for the Elderly: A Review of the Literature
Fluid intake monitoring is an essential component in preventing dehydration and overhydration, especially for the senior population. Numerous critical health problems are associated with poor or excessive drinking such as swelling of the brain and heart failure. Real-time systems for monitoring fluid intake will not only measure the exact amount consumed by the users, but could also motivate people to maintain a healthy lifestyle by providing feedback to encourage them to hydrate regularly throughout the day. This paper reviews the most recent solutions to automatic fluid intake monitoring both commercially and in the literature. The available technologies are divided into four categories: wearables, surfaces with embedded sensors, vision- and environmental-based solutions, and smart containers. A detailed performance evaluation was carried out considering detection accuracy, usability and availability. It was observed that the most promising results came from studies that used data fusion from multiple technologies, compared to using an individual technology. The areas that need further research and the challenges for each category are discussed in detail
A novel wearable biofeedback system to prevent trip-related falls
Real-time gait monitoring of older adults and gait-impaired individuals while providing real-time biofeedback has the potential to help reduce trip-related falls. A low or unsuccessful Minimum Toe Clearance (MTC) is considered a predictor of tripping risk. Thus, increasing the MTC can be a key component in minimizing the likelihood of tripping. This paper discusses a proof-of-concept wearable system that estimates the MTC in real-time using two Time-of-Flight (ToF) sensors and provides auditory biofeedback to alert users if they have a low MTC during everyday walking activities. Ten healthy female adults were asked to perform two experiments: 1) walk at a predetermined speed to evaluate the proposed real-time MTC detection algorithm, and 2) walk in four conditions: baseline, biofeedback with no distraction, biofeedback with distraction 1 (talking on the phone), and biofeedback with distraction 2 (playing a simple mobile game). The average MTC values were significantly greater during all feedback conditions than the baseline, indicating that the proposed system could successfully warn users to increase their MTC in real-time
Influential Factors in Remote Monitoring of Heart Failure Patients: A Review of the Literature and Direction for Future Research
With new advances in technology, remote monitoring of heart failure (HF) patients has become increasingly prevalent and has the potential to greatly enhance the outcome of care. Many studies have focused on implementing systems for the management of HF by analyzing physiological signals for the early detection of HF decompensation. This paper reviews recent literature exploring significant physiological variables, compares their reliability in predicting HF-related events, and examines the findings according to the monitored variables used such as body weight, bio-impedance, blood pressure, heart rate, and respiration rate. The reviewed studies identified correlations between the monitored variables and the number of alarms, HF-related events, and/or readmission rates. It was observed that the most promising results came from studies that used a combination of multiple parameters, compared to using an individual variable. The main challenges discussed include inaccurate data collection leading to contradictory outcomes from different studies, compliance with daily monitoring, and consideration of additional factors such as physical activity and diet. The findings demonstrate the need for a shared remote monitoring platform which can lead to a significant reduction of false alarms and help in collecting reliable data from the patients for clinical use especially for the prevention of cardiac events
Design of a Novel Wearable System for Foot Clearance Estimation
Trip-related falls are one of the major causes of injury among seniors in Canada and can be attributable to an inadequate Minimum Toe Clearance (MTC). Currently, motion capture systems are the gold standard for measuring MTC; however, they are expensive and have a restricted operating area. In this paper, a novel wearable system is proposed that can estimate different foot clearance parameters accurately using only two Time-of-Flight (ToF) sensors located at the toe and heel of the shoe. A small-scale preliminary study was conducted to investigate the feasibility of foot clearance estimation using the proposed wearable system. We recruited ten young, healthy females to walk at three self-selected speeds (normal, slow, and fast) while wearing the system. Our data analysis showed an average correlation coefficient of 0.94, 0.94, 0.92 for the normal, slow, and fast speed, respectively, when comparing the ToF signals with motion capture. The ANOVA analysis confirmed these results further by revealing no statistically significant differences between the ToF signals and motion capture data for most of the gait parameters after applying the newly proposed foot angle and offset compensation. In addition, the proposed system can measure the MTC with an average Mean Error (ME) of −0.08 ± 3.69 mm, −0.12 ± 4.25 mm, and −0.10 ± 6.57 mm for normal, slow, and fast walking speeds, respectively. The proposed affordable wearable system has the potential to perform real-time MTC estimation and contribute to future work focused on minimizing tripping risks
A Vision-Based Approach for Sidewalk and Walkway Trip Hazards Assessment
Tripping hazards on the sidewalk cause many falls annually, and the inspection and repair of these hazards cost cities millions of dollars. Currently, there is not an efficient and cost-effective method to monitor the sidewalk to identify any possible tripping hazards. In this paper, a new portable device is proposed using an Intel RealSense D415 RGB-D camera to monitor the sidewalks, detect the hazards, and extract relevant features of the hazards. This paper first analyzes the effects of environmental factors contributing to the device’s error and compares different regression techniques to calibrate the camera. The Gaussian Process Regression models yielded the most accurate predictions with less than 0.09 mm Mean Absolute Errors (MAEs). In the second phase, a novel segmentation algorithm is proposed that combines the edge detection and region-growing techniques to detect the true tripping hazards. Different examples are provided to visualize the output results of the proposed method