Search results for: time and motion study
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 58572

Search results for: time and motion study

58092 Simulation of Pedestrian Service Time at Different Delay Times

Authors: Imran Badshah

Abstract:

Pedestrian service time reflects the performance of the facility, and it’s a key parameter to analyze the capability of facilities provided to serve pedestrians. The level of service of pedestrians (LOS) mainly depends on pedestrian time and safety. The pedestrian time utilized by taking a service is mainly influenced by the number of available services and the time utilized by each pedestrian in receiving a service; that is called a delay time. In this paper, we analyzed the simulated pedestrian service time with different delay times. A simulation is performed in AnyLogic by developing a model that reflects the real scenario of pedestrian services such as ticket machine gates at rail stations, airports, shopping malls, and cinema halls. The simulated pedestrian time is determined for various delay values. The simulated result shows how pedestrian time changes with the delay pattern. The histogram and time plot graph of a model gives the mean, maximum and minimum values of the pedestrian time. This study helps us to check the behavior of pedestrian time at various services such as subway stations, airports, shopping malls, and cinema halls.

Keywords: agent-based simulation, anylogic model, pedestrian behavior, time delay

Procedia PDF Downloads 210
58091 The Correlation between Musculoskeletal Disorders and Body Postures during Playing among Guitarists

Authors: Navah Z. Ratzon, Shlomit Cohen, Sigal Portnoy

Abstract:

This work focuses on posture and risk factors for the musculoskeletal disorder in guitarists, which constitutes the largest group of musicians today. The source of the problems experienced by these musicians is linked to physical, psychosocial and personal risk factors. These muscular problems are referred to as Playing Related Musculoskeletal Disorder (PRMD). There is not enough research that specifically studies guitar players, and to the extent of our knowledge, there is almost no reference to the characteristics of their movement patterns while they play. This is in spite of the high prevalence of PRMD in this population. Kinematic research may provide a basis for the development of a prevention plan for this population and their unique characteristics of playing patterns. The aim of the study was to investigate the correlation between risk factors for PRMD among guitar players and self-reporting of pain in the skeletal muscles, and specifically to test whether there are differences in the kinematics of the upper body while playing in a sitting or standing posture. Twenty-five guitarists, aged 18-35, participated in the study. The methods included a motion analysis using a motion capture system, anthropometric measurements and questionnaires relating to risk factors. The questionnaires used were the Standardized Nordic Questionnaire for the Analysis of Musculoskeletal Symptoms and the Demand Control Support Questionnaire, as well as a questionnaire of personal details. All of the study participants complained of musculoskeletal pain in the past year; the most frequent complaints being in the left wrist. Statistically significant correlations were found between biodemographic indices and reports of pain in the past year and the previous week. No significant correlations were found between the physical posture while playing and reports of pain among professional guitarists. However, a difference was found in several kinematic parameters between seated and standing playing postures. In a majority of the joints, the joint angles while playing in a seated position were more extreme than those during standing. This finding may suggest a higher risk for musculoskeletal disorder while playing in a seated position. In conclusion, the results of the present research highlight the prevalence of musculoskeletal problems in guitar players and its correlation with various risk factors. The finding supports the need for intervention in the form of prevention through identifying the risk factors and addressing them. Relating to the person, to their occupation and environment, which are the basis of proper occupational therapy, can help meet this need.

Keywords: body posture, motion tracking, PRMD, guitarists

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58090 Studies on Space-Based Laser Targeting System for the Removal of Orbital Space Debris

Authors: Krima M. Rohela, Raja Sabarinath Sundaralingam

Abstract:

Humans have been launching rockets since the beginning of the space age in the late 1950s. We have come a long way since then, and the success rate for the launch of rockets has increased considerably. With every successful launch, there is a large amount of junk or debris which is released into the upper layers of the atmosphere. Space debris has been a huge concern for a very long time now. This includes the rocket shells released from the launch and the parts of defunct satellites. Some of this junk will come to fall towards the Earth and burn in the atmosphere. But most of the junk goes into orbit around the Earth, and they remain in orbits for at least 100 years. This can cause a lot of problems to other functioning satellites and may affect the future manned missions to space. The main concern of the space-debris is the increase in space activities, which leads to risks of collisions if not taken care of soon. These collisions may result in what is known as Kessler Syndrome. This debris can be removed by a space-based laser targeting system. Hence, the matter is investigated and discussed. The first step in this involves launching a satellite with a high-power laser device into space, above the debris belt. Then the target material is ablated with a focussed laser beam. This step of the process is highly dependent on the attitude and orientation of the debris with respect to the Earth and the device. The laser beam will cause a jet of vapour and plasma to be expelled from the material. Hence, the force is applied in the opposite direction, and in accordance with Newton’s third law of motion, this will cause the material to move towards the Earth and get pulled down due to gravity, where it will get disintegrated in the upper layers of the atmosphere. The larger pieces of the debris can be directed towards the oceans. This method of removal of the orbital debris will enable safer passage for future human-crewed missions into space.

Keywords: altitude, Kessler syndrome, laser ablation, Newton’s third law of motion, satellites, Space debris

Procedia PDF Downloads 149
58089 A Deep Learning-Based Pedestrian Trajectory Prediction Algorithm

Authors: Haozhe Xiang

Abstract:

With the rise of the Internet of Things era, intelligent products are gradually integrating into people's lives. Pedestrian trajectory prediction has become a key issue, which is crucial for the motion path planning of intelligent agents such as autonomous vehicles, robots, and drones. In the current technological context, deep learning technology is becoming increasingly sophisticated and gradually replacing traditional models. The pedestrian trajectory prediction algorithm combining neural networks and attention mechanisms has significantly improved prediction accuracy. Based on in-depth research on deep learning and pedestrian trajectory prediction algorithms, this article focuses on physical environment modeling and learning of historical trajectory time dependence. At the same time, social interaction between pedestrians and scene interaction between pedestrians and the environment were handled. An improved pedestrian trajectory prediction algorithm is proposed by analyzing the existing model architecture. With the help of these improvements, acceptable predicted trajectories were successfully obtained. Experiments on public datasets have demonstrated the algorithm's effectiveness and achieved acceptable results.

Keywords: deep learning, graph convolutional network, attention mechanism, LSTM

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58088 Studying Frame-Resistant Steel Structures under Near Field Ground Motion

Authors: S. A. Hashemi, A. Khoshraftar

Abstract:

This paper presents the influence of the vertical seismic component on the non-linear dynamics analysis of three different structures. The subject structures were analyzed and designed according to recent codes. This paper considers three types of buildings: 5-, 10-, and 15-story buildings. The non-linear dynamics analysis of the structures with assuming elastic-perfectly-plastic behavior was performed using Ram Perform-3D software; the horizontal component was taken into consideration with and without the incorporation of the corresponding vertical component. Dynamic responses obtained for the horizontal component acting alone were compared with those obtained from the simultaneous application of both seismic components. The results show that the effect of the vertical component of the ground motion may increase the axial load significantly in the interior columns and consequently, the stories. The plastic mechanisms would be changed. The P-Delta effect is expected to increase. The punching base plate shear of the columns should be considered. Moreover, the vertical component increases the input energy when the structures exhibit inelastic behavior and are taller.

Keywords: inelastic behavior, non-linear dynamic analysis, steel structure, vertical component

Procedia PDF Downloads 317
58087 Ground Motion Modelling in Bangladesh Using Stochastic Method

Authors: Mizan Ahmed, Srikanth Venkatesan

Abstract:

Geological and tectonic framework indicates that Bangladesh is one of the most seismically active regions in the world. The Bengal Basin is at the junction of three major interacting plates: the Indian, Eurasian, and Burma Plates. Besides there are many active faults within the region, e.g. the large Dauki fault in the north. The country has experienced a number of destructive earthquakes due to the movement of these active faults. Current seismic provisions of Bangladesh are mostly based on earthquake data prior to the 1990. Given the record of earthquakes post 1990, there is a need to revisit the design provisions of the code. This paper compares the base shear demand of three major cities in Bangladesh: Dhaka (the capital city), Sylhet, and Chittagong for earthquake scenarios of magnitudes 7.0MW, 7.5MW, 8.0MW and 8.5MW using a stochastic model. In particular, the stochastic model allows the flexibility to input region specific parameters such as shear wave velocity profile (that were developed from Global Crustal Model CRUST2.0) and include the effects of attenuation as individual components. Effects of soil amplification were analysed using the Extended Component Attenuation Model (ECAM). Results show that the estimated base shear demand is higher in comparison with code provisions leading to the suggestion of additional seismic design consideration in the study regions.

Keywords: attenuation, earthquake, ground motion, Stochastic, seismic hazard

Procedia PDF Downloads 249
58086 Optimization of Bills Assignment to Different Skill-Levels of Data Entry Operators in a Business Process Outsourcing Industry

Authors: M. S. Maglasang, S. O. Palacio, L. P. Ogdoc

Abstract:

Business Process Outsourcing has been one of the fastest growing and emerging industry in the Philippines today. Unlike most of the contact service centers, more popularly known as "call centers", The BPO Industry’s primary outsourced service is performing audits of the global clients' logistics. As a service industry, manpower is considered as the most important yet the most expensive resource in the company. Because of this, there is a need to maximize the human resources so people are effectively and efficiently utilized. The main purpose of the study is to optimize the current manpower resources through effective distribution and assignment of different types of bills to the different skill-level of data entry operators. The assignment model parameters include the average observed time matrix gathered from through time study, which incorporates the learning curve concept. Subsequently, a simulation model was made to duplicate the arrival rate of demand which includes the different batches and types of bill per day. Next, a mathematical linear programming model was formulated. Its objective is to minimize direct labor cost per bill by allocating the different types of bills to the different skill-levels of operators. Finally, a hypothesis test was done to validate the model, comparing the actual and simulated results. The analysis of results revealed that the there’s low utilization of effective capacity because of its failure to determine the product-mix, skill-mix, and simulated demand as model parameters. Moreover, failure to consider the effects of learning curve leads to overestimation of labor needs. From 107 current number of operators, the proposed model gives a result of 79 operators. This results to an increase of utilization of effective capacity to 14.94%. It is recommended that the excess 28 operators would be reallocated to the other areas of the department. Finally, a manpower capacity planning model is also recommended in support to management’s decisions on what to do when the current capacity would reach its limit with the expected increasing demand.

Keywords: optimization modelling, linear programming, simulation, time and motion study, capacity planning

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58085 Comparative Study of Active Release Technique and Myofascial Release Technique in Patients with Upper Trapezius Spasm

Authors: Harihara Prakash Ramanathan, Daksha Mishra, Ankita Dhaduk

Abstract:

Relevance: This qualitative study will educate the clinician in putting into practice the advanced method of movement science in restoring the function. Purpose: The purpose of this study is to compare the effectiveness of Active Release Technique and myofascial release technique on range of motion, neck function and pain in patients with upper trapezius spasm. Methods/Analysis: The study was approved by the institutional Human Research and Ethics committee. This study included sixty patients of age group between 20 to 55 years with upper trapezius spasm. Patients were randomly divided into two groups receiving Active Release Technique (Group A) and Myofascial Release Technique (Group B). The patients were treated for 1 week and three outcome measures ROM, pain and functional level were measured using Goniometer, Visual analog scale(VAS), Neck disability Index Questionnaire(NDI) respectively. Paired Sample 't' test was used to compare the differences of pre and post intervention values of Cervical Range of motion, Neck disability Index, Visual analog scale of Group A and Group B. Independent't' test was used to compare the differences between two groups in terms of improvement in cervical range of motion, decrease in visual analogue scale(VAS), decrease in Neck disability index score. Results: Both the groups showed statistically significant improvements in cervical ROM, reduction in pain and in NDI scores. However, mean change in Cervical flexion, cervical extension, right side flexion, left side flexion, right side rotation, left side rotation, pain, neck disability level showed statistically significant improvement (P < 0. 05)) in the patients who received Active Release Technique as compared to Myofascial release technique. Discussion and conclusions: In present study, the average improvement immediately post intervention is significantly greater as compared to before treatment but there is even more improvement after seven sessions as compared to single session. Hence, this proves that several sessions of Manual techniques are necessary to produce clinically relevant results. Active release technique help to reduce the pain threshold by removing adhesion and promote normal tissue extensibility. The act of tensioning and compressing the affected tissue both with digital contact and through the active movement performed by the patient can be a plausible mechanism for tissue healing in this study. This study concluded that both Active Release Technique (ART) and Myofascial release technique (MFR) are equally effective in managing upper trapezius muscle spasm, but more improvement can be achieved by Active Release Technique (ART). Impact and Implications: Active Release Technique can be adopted as mainstay of treatment approach in treating trapezius spasm for faster relief and improving the functional status.

Keywords: trapezius spasm, myofascial release, active release technique, pain

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58084 Crustal Deformation Study across the Chite Fault Using GPS Measurements in North East India along the Indo Burmese Arc

Authors: Malsawmtluanga, J. Malsawma, R. P. Tiwari, V. K. Gahalaut

Abstract:

North East India is seismically one of the six most active regions of the world. It is placed in Zone V, the highest zone in the seismic zonation of India. It lies at the junction of Himalayan arc to the north and the Burmese arc to the east. The region has witnessed at least 18 large earthquakes including two great earthquakes Shillong (1987, M=8.7) and the Assam Tibet border (1950, M=8.7).The prominent Chite fault lies at the heart of Aizawl, the capital of Mizoram state and this hilly city is the home to about 2 million people. Geologically the area is a part of the Indo-Burmese Wedge and is prone to natural and man-made disasters. Unplanned constructions and urban dwellings on a rapid scale have lead to numerous unsafe structures adversely affecting the ongoing development and welfare projects of the government and they pose a huge threat for earthquakes. Crustal deformation measurements using campaign mode GPS were undertaken across this fault. Campaign mode GPS data were acquired and were processed with GAMIT-GLOBK software. The study presents the current velocity estimates at all the sites in ITRF 2008 and also in the fixed Indian reference frame. The site motion showed that there appears to be no differential motion anywhere across the fault area, thus confirming presently the fault is neither accumulating strain nor slipping aseismically. From the geological and geomorphological evidence, supported by geodetic measurements, lack of historic earthquakes, the Chite fault favours aseismic behaviour in this part of the Indo Burmese Arc (IBA).

Keywords: Chite fault, crustal deformation, geodesy, GPS, IBA

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58083 Lineup Optimization Model of Basketball Players Based on the Prediction of Recursive Neural Networks

Authors: Wang Yichen, Haruka Yamashita

Abstract:

In recent years, in the field of sports, decision making such as member in the game and strategy of the game based on then analysis of the accumulated sports data are widely attempted. In fact, in the NBA basketball league where the world's highest level players gather, to win the games, teams analyze the data using various statistical techniques. However, it is difficult to analyze the game data for each play such as the ball tracking or motion of the players in the game, because the situation of the game changes rapidly, and the structure of the data should be complicated. Therefore, it is considered that the analysis method for real time game play data is proposed. In this research, we propose an analytical model for "determining the optimal lineup composition" using the real time play data, which is considered to be difficult for all coaches. In this study, because replacing the entire lineup is too complicated, and the actual question for the replacement of players is "whether or not the lineup should be changed", and “whether or not Small Ball lineup is adopted”. Therefore, we propose an analytical model for the optimal player selection problem based on Small Ball lineups. In basketball, we can accumulate scoring data for each play, which indicates a player's contribution to the game, and the scoring data can be considered as a time series data. In order to compare the importance of players in different situations and lineups, we combine RNN (Recurrent Neural Network) model, which can analyze time series data, and NN (Neural Network) model, which can analyze the situation on the field, to build the prediction model of score. This model is capable to identify the current optimal lineup for different situations. In this research, we collected all the data of accumulated data of NBA from 2019-2020. Then we apply the method to the actual basketball play data to verify the reliability of the proposed model.

Keywords: recurrent neural network, players lineup, basketball data, decision making model

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58082 Impacts on the Modification of a Two-Blade Mobile on the Agitation of Newtonian Fluids

Authors: Abderrahim Sidi Mohammed Nekrouf, Sarra Youcefi

Abstract:

Fluid mixing plays a crucial role in numerous industries as it has a significant impact on the final product quality and performance. In certain cases, the circulation of viscous fluids presents challenges, leading to the formation of stagnant zones. To overcome this issue, stirring devices are employed for fluid mixing. This study focuses on a numerical analysis aimed at understanding the behavior of Newtonian fluids when agitated by a two-blade agitator in a cylindrical vessel. We investigate the influence of the agitator shape on fluid motion. Bi-blade agitators of this type are commonly used in the food, cosmetic, and chemical industries to agitate both viscous and non-viscous liquids. Numerical simulations were conducted using Computational Fluid Dynamics (CFD) software to obtain velocity profiles, streamlines, velocity contours, and the associated power number. The obtained results were compared with experimental data available in the literature, validating the accuracy of our numerical approach. The results clearly demonstrate that modifying the agitator shape has a significant impact on fluid motion. This modification generates an axial flow that enhances the efficiency of the fluid flow. The various velocity results convincingly reveal that the fluid is more uniformly agitated with this modification, resulting in improved circulation and a substantial reduction in stagnant zones.

Keywords: Newtonian fluids, numerical modeling, two blade., CFD

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58081 The Application of FSI Techniques in Modeling of Realist Pulmonary Systems

Authors: Abdurrahim Bolukbasi, Hassan Athari, Dogan Ciloglu

Abstract:

The modeling lung respiratory system which has complex anatomy and biophysics presents several challenges including tissue-driven flow patterns and wall motion. Also, the lung pulmonary system because of that they stretch and recoil with each breath, has not static walls and structures. The direct relationship between air flow and tissue motion in the lung structures naturally prefers an FSI simulation technique. Therefore, in order to toward the realistic simulation of pulmonary breathing mechanics the development of a coupled FSI computational model is an important step. A simple but physiologically-relevant three dimensional deep long geometry is designed and fluid-structure interaction (FSI) coupling technique is utilized for simulating the deformation of the lung parenchyma tissue which produces airflow fields. The real understanding of respiratory tissue system as a complex phenomenon have been investigated with respect to respiratory patterns, fluid dynamics and tissue visco-elasticity and tidal breathing period.

Keywords: lung deformation and mechanics; Tissue mechanics; Viscoelasticity; Fluid-structure interactions; ANSYS

Procedia PDF Downloads 323
58080 Memory, Self, and Time: A Bachelardian Perspective

Authors: Michael Granado

Abstract:

The French philosopher Gaston Bachelard’s philosophy of time is articulated in his two works on the subject, the Intuition of the Instant (1932) and his The Dialectic of Duration (1936). Both works present a systematic methodology predicated upon the assumption that our understanding of time has radically changed as a result of Einstein and subsequently needs to be reimagined. Bachelard makes a major distinction in his discussion of time: 1. Time as it is (physical time), 2. Time as we experience it (phenomenological time). This paper will focus on the second distinction, phenomenological time, and explore the connections between Bachelard’s work and contemporary psychology. Several aspects of Bachelard’s philosophy of time nicely complement our current understanding of memory and self and clarify how the self relates to experienced time. Two points, in particular, stand out; the first is the relative nature of subjective time, and the second is the implications of subjective time in the formation of the narrative self. Bachelard introduces two philosophical concepts to explain these points: rhythmanalysis and reverie. By exploring these concepts, it will become apparent that there is an undeniable link between memory, self, and time. Through the use of narrative self, the individual connects and links memories and time together to form a sense of personal identity.

Keywords: Gaston Bachelard, memory, self, time

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58079 Implication of Soil and Seismic Ground Motion Variability on Dynamic Pile Group Impedance for Bridges

Authors: Muhammad Tariq Chaudhary

Abstract:

Bridges constitute a vital link in a transportation system and their functionality after an earthquake is critical in reducing disruption to social and economic activities of the society. Bridges supported on pile foundations are commonly used in many earthquake-prone regions. In order to properly design or investigate the performance of such structures, it is imperative that the effect of soil-foundation-structure interaction be properly taken into account. This study focused on the influence of soil and seismic ground motion variability on the dynamic impedance of pile-group foundations typically used for medium-span (about 30 m) urban viaduct bridges. Soil profiles corresponding to various AASHTO soil classes were selected from actual data of such bridges and / or from the literature. The selected soil profiles were subjected to 1-D wave propagation analysis to determine effective values of soil shear modulus and damping ratio for a suite of properly selected actual seismic ground motions varying in PGA from 0.01g to 0.64g, and having variable velocity and frequency content. The effective values of the soil parameters were then employed to determine the dynamic impedance of pile groups in horizontal, vertical and rocking modes in various soil profiles. Pile diameter was kept constant for bridges in various soil profiles while pile length and number of piles were changed based on AASHTO design requirements for various soil profiles and earthquake ground motions. Conclusions were drawn regarding variability in effective soil shear modulus, soil damping, shear wave velocity and pile group impedance for various soil profiles and ground motions and its implications for design and evaluation of pile-supported bridges. It was found that even though the effective soil parameters underwent drastic variation with increasing PGA, the pile group impedance was not affected much in properly designed pile foundations due to the corresponding increase in pile length or increase in a number of piles or both when subjected to increasing PGA or founded in weaker soil profiles.

Keywords: bridge, pile foundation, dynamic foundation impedance, soil profile, shear wave velocity, seismic ground motion, seismic wave propagation

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58078 Development of Precise Ephemeris Generation Module for Thaichote Satellite Operations

Authors: Manop Aorpimai, Ponthep Navakitkanok

Abstract:

In this paper, the development of the ephemeris generation module used for the Thaichote satellite operations is presented. It is a vital part of the flight dynamics system, which comprises, the orbit determination, orbit propagation, event prediction and station-keeping maneuver modules. In the generation of the spacecraft ephemeris data, the estimated orbital state vector from the orbit determination module is used as an initial condition. The equations of motion are then integrated forward in time to predict the satellite states. The higher geopotential harmonics, as well as other disturbing forces, are taken into account to resemble the environment in low-earth orbit. Using a highly accurate numerical integrator based on the Burlish-Stoer algorithm the ephemeris data can be generated for long-term predictions, by using a relatively small computation burden and short calculation time. Some events occurring during the prediction course that are related to the mission operations, such as the satellite’s rise/set viewed from the ground station, Earth and Moon eclipses, the drift in ground track as well as the drift in the local solar time of the orbital plane are all detected and reported. When combined with other modules to form a flight dynamics system, this application is aimed to be applied for the Thaichote satellite and successive Thailand’s Earth-observation missions.

Keywords: flight dynamics system, orbit propagation, satellite ephemeris, Thailand’s Earth Observation Satellite

Procedia PDF Downloads 377
58077 Application of Rapid Prototyping to Create Additive Prototype Using Computer System

Authors: Meftah O. Bashir, Fatma A. Karkory

Abstract:

Rapid prototyping is a new group of manufacturing processes, which allows fabrication of physical of any complexity using a layer by layer deposition technique directly from a computer system. The rapid prototyping process greatly reduces the time and cost necessary to bring a new product to market. The prototypes made by these systems are used in a range of industrial application including design evaluation, verification, testing, and as patterns for casting processes. These processes employ a variety of materials and mechanisms to build up the layers to build the part. The present work was to build a FDM prototyping machine that could control the X-Y motion and material deposition, to generate two-dimensional and three-dimensional complex shapes. This study focused on the deposition of wax material. This work was to find out the properties of the wax materials used in this work in order to enable better control of the FDM process. This study will look at the integration of a computer controlled electro-mechanical system with the traditional FDM additive prototyping process. The characteristics of the wax were also analysed in order to optimize the model production process. These included wax phase change temperature, wax viscosity and wax droplet shape during processing.

Keywords: rapid prototyping, wax, manufacturing processes, shape

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58076 Design of a Robot with a Transformable Track System in Tackling Motion Barrier

Authors: Kai-Yi Cho, Fa-Shian Chang, Lih-Tyng Hwang, Chih-Feng Liu, Jeng-Nan Lee, Shun-Min Wang, Jhu-Wei Ji

Abstract:

This paper presents a ground robot which has the tracked transformative structures of the motion mechanism. The robot has a good ability to adapt to the terrain, due to the front end of the track can be deformed, it can more easily pass the more complex area, such as to climb stairs and ramp areas. Usually in the disaster area, where the terrain is generally broken and complicated, there will be many slopes, broken walls, rubble, and obstacles, then if you want the robot through this area, you need to have a good off-road performance for possible complex terrain, this robot with the transformative tracked mechanism has a strong adaptability, it can overcome the limitation of the terrains to be a good rescue robot. Also, the robot has a good flexibility in the shape of contact with the ground; that can adapt the varied terrain by the deformable track, thus able to pass the different terrains, that was verified through the experiments on a test-platform and a field test. The prototype of the robot system has been developed, and experiments are carried out to verify the validity of the proposed design.

Keywords: tracked robot, rescue robot, transformation mechanism, deformable track, hull design

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58075 An Engineering Application of the H-P Version of the Finite Element Method on Vibration Behavior of Rotors

Authors: Hadjoui Abdelhamid, Saimi Ahmed

Abstract:

The hybrid h-p finite element method for the dynamic behavior of nonlinear rotors is described in this paper. The standard h-version method of discretizing the problem is retained, but modified to allow the use of polynomially-enriched beam elements. A hierarchically enriching element will thus not affect the nodal displacement and rotation, but will influence the values of the nodal bending moment and shear force is used. The deterministic movements of rotation and translation of the support which are coupled to the excitations due to unbalance are also taken into account. We study also the geometric dissymmetry of the shaft and the disc, thus the equations of motion of the rotor contain variable parametric coefficients over time that can lead to a lateral dynamic instability. The effects of movements combined support for bearings are analyzed and discussed through Campbell diagrams and spectral analyses. A program is made in Matlab. After validation of the program, several examples are studied. The influence of physical and geometric parameters on the natural frequencies of the shaft is determined through the study of these examples. Among these parameters, we include the variation in the diameter and the thickness of the rotor, the position of the disc.

Keywords: Campbell diagram, critical speeds, nonlinear rotor, version h-p of FEM

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58074 Rehabilitative Walking: The Development of a Robotic Walking Training Device Using Functional Electrical Stimulation for Treating Spinal Cord Injuries and Lower-Limb Paralysis

Authors: Chung Hyun Goh, Armin Yazdanshenas, X. Neil Dong, Yong Tai Wang

Abstract:

Physical rehabilitation is a necessary step in regaining lower body function after a partial paralysis caused by a spinal cord injury or a stroke. The purpose of this paper is to present the development and optimization of a training device that accurately recreates the motions in a gait cycle with the goal of rehabilitation for individuals with incomplete spinal cord injuries or who are victims of a stroke. A functional electrical stimulator was used in conjunction with the training device to stimulate muscle groups pertaining to rehabilitative walking. The feasibility and reliability of the design are presented. To validate the design functionality, motion analyses of the knee and ankle gait paths were made using motion capture systems. Key results indicate that the robotic walking training device provides a viable mode of physical rehabilitation.

Keywords: functional electrical stimulation, rehabilitative walking, robotic walking training device, spinal cord injuries

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58073 Project Time Prediction Model: A Case Study of Construction Projects in Sindh, Pakistan

Authors: Tauha Hussain Ali, Shabir Hussain Khahro, Nafees Ahmed Memon

Abstract:

Accurate prediction of project time for planning and bid preparation stage should contain realistic dates. Constructors use their experience to estimate the project duration for the new projects, which is based on intuitions. It has been a constant concern to both researchers and constructors to analyze the accurate prediction of project duration for bid preparation stage. In Pakistan, such study for time cost relationship has been lacked to predict duration performance for the construction projects. This study is an attempt to explore the time cost relationship that would conclude with a mathematical model to predict the time for the drainage rehabilitation projects in the province of Sindh, Pakistan. The data has been collected from National Engineering Services (NESPAK), Pakistan and regression analysis has been carried out for the analysis of results. Significant relationship has been found between time and cost of the construction projects in Sindh and the generated mathematical model can be used by the constructors to predict the project duration for the upcoming projects of same nature. This study also provides the professionals with a requisite knowledge to make decisions regarding project duration, which is significantly important to win the projects at the bid stage.

Keywords: BTC Model, project time, relationship of time cost, regression

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58072 Investigating the Effect of High Intensity Laser and Dry Needling in Patients with Chronic Neck Pain

Authors: Marzieh Yassin, Azizeh Parandnia, Javad Sarrafzadeh, Reza Salehi

Abstract:

Background: Myofascial trigger points (MTrPs) are one of the main causes of musculoskeletal pain syndromes and are associated with pain, tenderness, and limited range of motion (ROM). This study compared the effectiveness of high-intensity laser therapy (HILT) and dry needling (DN) on pain intensity, pain pressure threshold, cervical range of motion and disability in people with chronic neck pain. Method and Material: 30 patients with chronic neck pain were randomly divided into two groups: a HILT group (n=15) and a DN group (n=15). Treatment sessions were performed for three weeks, and all participants received related intervention twice a week (5 sessions). The pain level was measured using a Visual Analog Scale (VAS); the pain pressure threshold (PPT) was measured using a digital algometer; perceived disability was measured using the neck disability index (NDI); and cervical range of movements (CROMs) were measured using an iPhone app (lateral flexion) and a goniometer (Rotation). Results: In both the dry needling and high-intensity laser therapy groups, the pain and neck disability were significantly decreased (P < 0.05). Also, the pain pressure threshold and cervical range of motions were significantly increased in both groups. However, there was no significant difference between the two groups (P > 0.05). Conclusion: Both high-intensity laser therapy and dry needling can be used to treat chronic neck pain.

Keywords: chronic neck pain, dry needling, high intensity laser therapy (HILT), pain, pain pressure threshold

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58071 Evaluation of Sloshing in Process Equipment for Floating Cryogenic Application

Authors: Bo Jin

Abstract:

A variety of process equipment having flow in and out is widely used in industrial land-based cryogenic facilities. In some of this equipment, such as vapor-liquid separator, a liquid level is established during the steady operation. As the implementation of such industrial processes extends to off-shore floating facilities, it is important to investigate the effect of sea motion on the process equipment partially filled with liquid. One important aspect to consider is the occurrence of sloshing therein. The flow characteristics are different from the classical study of sloshing, where the fluid is enclosed inside a vessel (e.g., storage tank) with no flow in or out. Liquid inside process equipment continuously flows in and out of the system. To understand this key difference, a Computational Fluid Dynamics (CFD) model is developed to simulate the liquid motion inside a partially filled cylinder with and without continuous flow in and out. For a partially filled vertical cylinder without any continuous flow in and out, the CFD model is found to be able to capture the well-known sloshing behavior documented in the literature. For the cylinder with a continuous steady flow in and out, the CFD simulation results demonstrate that the continuous flow suppresses sloshing. Given typical cryogenic fluid has very low viscosity, an analysis based on potential flow theory is developed to explain why flow into and out of the cylinder changes the natural frequency of the system and thereby suppresses sloshing. This analysis further validates the CFD results.

Keywords: computational fluid dynamics, CFD, cryogenic process equipment, off-shore floating processes, sloshing

Procedia PDF Downloads 137
58070 The Temporal Dimension of Narratives: A Construct of Qualitative Time

Authors: Ani Thomas

Abstract:

Every narrative is a temporal construct. Every narrative creates a qualitative experience of time for the viewer. The paper argues for the concept of a qualified time that emerges from the interaction between the narrative and the audience. The paper also challenges the conventional understanding of narrative time as either story time, real time or discourse time. Looking at narratives through the medium of Cinema, the study examines how narratives create and manipulate duration or durée, the qualitative experience of time as theorized by Henri Bergson. The paper further analyzes how Cinema and, by extension, narratives are nothing but Durée and the filmmaker, the artist of durée, who shape and manipulate the perception and emotions of the viewer through the manipulation and construction of durée. The paper draws on cinematic works to look at the techniques to demonstrate how filmmakers use, for example, editing, sound, compositional and production narratives etc., to create various modes of durée that challenge, amplify or unsettle the viewer’s sense of time. Bringing together the Viewer’s durée and exploring its interaction with the narrative construct, the paper explores the emergence of the new qualitative time, the narrative durée, that defines the audience experience.

Keywords: cinema, time, bergson, duree

Procedia PDF Downloads 148
58069 Optical Flow Based System for Cross Traffic Alert

Authors: Giuseppe Spampinato, Salvatore Curti, Ivana Guarneri, Arcangelo Bruna

Abstract:

This document describes an advanced system and methodology for Cross Traffic Alert (CTA), able to detect vehicles that move into the vehicle driving path from the left or right side. The camera is supposed to be not only on a vehicle still, e.g. at a traffic light or at an intersection, but also moving slowly, e.g. in a car park. In all of the aforementioned conditions, a driver’s short loss of concentration or distraction can easily lead to a serious accident. A valid support to avoid these kinds of car crashes is represented by the proposed system. It is an extension of our previous work, related to a clustering system, which only works on fixed cameras. Just a vanish point calculation and simple optical flow filtering, to eliminate motion vectors due to the car relative movement, is performed to let the system achieve high performances with different scenarios, cameras and resolutions. The proposed system just uses as input the optical flow, which is hardware implemented in the proposed platform and since the elaboration of the whole system is really speed and power consumption, it is inserted directly in the camera framework, allowing to execute all the processing in real-time.

Keywords: clustering, cross traffic alert, optical flow, real time, vanishing point

Procedia PDF Downloads 203
58068 Modeling User Departure Time Choice for Trips in Urban Streets

Authors: Saeed Sayyad Hagh Shomar

Abstract:

Modeling users’ decisions on departure time choice is the main motivation for this research. In particular, it examines the impact of social-demographic features, household, job characteristics and trip qualities on individuals’ departure time choice. Departure time alternatives are presented as adjacent discrete time periods. The choice between these alternatives is done using a discrete choice model. Since a great deal of early morning trips and traffic congestion at that time of the day comprise work trips, the focus of this study is on the work trip over the entire day. Therefore, this study by using questionnaire of stated preference models users’ departure time choice affected by congestion pricing plan in downtown Tehran. Experimental results demonstrate efficient social-demographic impact on work trips’ departure time. These findings have substantial outcomes for the analysis of transportation planning. Particularly, the analysis shows that ignoring the effects of these variables could result in erroneous information and consequently decisions in the field of transportation planning and air quality would fail and cause financial resources loss.

Keywords: modeling, departure time, travel timing, time of the day, congestion pricing, transportation planning

Procedia PDF Downloads 433
58067 Investigating the Effect of VR, Time Study and Ergonomics on the Design of Industrial Workstations

Authors: Aydin Azizi, Poorya Ghafoorpoor Yazdi

Abstract:

This paper presents the review of the studies on the ergonomics, virtual reality, and work measurement (time study) at the industrial workstations because each of these three individual techniques can be used to improve the design of workstations and task position. The objective of this paper is to give an overall literature review that if there is any relation between these three different techniques. Therefore, it is so important to review the scientific studies to find a better and effective way for improving design of workstations. On the other hand, manufacturers found that instead of using one of the approaches, utilizing the combination of these individual techniques are more effective to reduce the cost and production time.

Keywords: ergonomics, time study, virtual reality, workplace

Procedia PDF Downloads 119
58066 VeriFy: A Solution to Implement Autonomy Safely and According to the Rules

Authors: Michael Naderhirn, Marco Pavone

Abstract:

Problem statement, motivation, and aim of work: So far, the development of control algorithms was done by control engineers in a way that the controller would fit a specification by testing. When it comes to the certification of an autonomous car in highly complex scenarios, the challenge is much higher since such a controller must mathematically guarantee to implement the rules of the road while on the other side guarantee aspects like safety and real time executability. What if it becomes reality to solve this demanding problem by combining Formal Verification and System Theory? The aim of this work is to present a workflow to solve the above mentioned problem. Summary of the presented results / main outcomes: We show the usage of an English like language to transform the rules of the road into system specification for an autonomous car. The language based specifications are used to define system functions and interfaces. Based on that a formal model is developed which formally correctly models the specifications. On the other side, a mathematical model describing the systems dynamics is used to calculate the systems reachability set which is further used to determine the system input boundaries. Then a motion planning algorithm is applied inside the system boundaries to find an optimized trajectory in combination with the formal specification model while satisfying the specifications. The result is a control strategy which can be applied in real time independent of the scenario with a mathematical guarantee to satisfy a predefined specification. We demonstrate the applicability of the method in simulation driving scenarios and a potential certification. Originality, significance, and benefit: To the authors’ best knowledge, it is the first time that it is possible to show an automated workflow which combines a specification in an English like language and a mathematical model in a mathematical formal verified way to synthesizes a controller for potential real time applications like autonomous driving.

Keywords: formal system verification, reachability, real time controller, hybrid system

Procedia PDF Downloads 241
58065 A Robust Visual Simultaneous Localization and Mapping for Indoor Dynamic Environment

Authors: Xiang Zhang, Daohong Yang, Ziyuan Wu, Lei Li, Wanting Zhou

Abstract:

Visual Simultaneous Localization and Mapping (VSLAM) uses cameras to collect information in unknown environments to realize simultaneous localization and environment map construction, which has a wide range of applications in autonomous driving, virtual reality and other related fields. At present, the related research achievements about VSLAM can maintain high accuracy in static environment. But in dynamic environment, due to the presence of moving objects in the scene, the movement of these objects will reduce the stability of VSLAM system, resulting in inaccurate localization and mapping, or even failure. In this paper, a robust VSLAM method was proposed to effectively deal with the problem in dynamic environment. We proposed a dynamic region removal scheme based on semantic segmentation neural networks and geometric constraints. Firstly, semantic extraction neural network is used to extract prior active motion region, prior static region and prior passive motion region in the environment. Then, the light weight frame tracking module initializes the transform pose between the previous frame and the current frame on the prior static region. A motion consistency detection module based on multi-view geometry and scene flow is used to divide the environment into static region and dynamic region. Thus, the dynamic object region was successfully eliminated. Finally, only the static region is used for tracking thread. Our research is based on the ORBSLAM3 system, which is one of the most effective VSLAM systems available. We evaluated our method on the TUM RGB-D benchmark and the results demonstrate that the proposed VSLAM method improves the accuracy of the original ORBSLAM3 by 70%˜98.5% under high dynamic environment.

Keywords: dynamic scene, dynamic visual SLAM, semantic segmentation, scene flow, VSLAM

Procedia PDF Downloads 116
58064 Multi-Criteria Selection and Improvement of Effective Design for Generating Power from Sea Waves

Authors: Khaled M. Khader, Mamdouh I. Elimy, Omayma A. Nada

Abstract:

Sustainable development is the nominal goal of most countries at present. In general, fossil fuels are the development mainstay of most world countries. Regrettably, the fossil fuel consumption rate is very high, and the world is facing the problem of conventional fuels depletion soon. In addition, there are many problems of environmental pollution resulting from the emission of harmful gases and vapors during fuel burning. Thus, clean, renewable energy became the main concern of most countries for filling the gap between available energy resources and their growing needs. There are many renewable energy sources such as wind, solar and wave energy. Energy can be obtained from the motion of sea waves almost all the time. However, power generation from solar or wind energy is highly restricted to sunny periods or the availability of suitable wind speeds. Moreover, energy produced from sea wave motion is one of the cheapest types of clean energy. In addition, renewable energy usage of sea waves guarantees safe environmental conditions. Cheap electricity can be generated from wave energy using different systems such as oscillating bodies' system, pendulum gate system, ocean wave dragon system and oscillating water column device. In this paper, a multi-criteria model has been developed using Analytic Hierarchy Process (AHP) to support the decision of selecting the most effective system for generating power from sea waves. This paper provides a widespread overview of the different design alternatives for sea wave energy converter systems. The considered design alternatives have been evaluated using the developed AHP model. The multi-criteria assessment reveals that the off-shore Oscillating Water Column (OWC) system is the most appropriate system for generating power from sea waves. The OWC system consists of a suitable hollow chamber at the shore which is completely closed except at its base which has an open area for gathering moving sea waves. Sea wave's motion pushes the air up and down passing through a suitable well turbine for generating power. Improving the power generation capability of the OWC system is one of the main objectives of this research. After investigating the effect of some design modifications, it has been concluded that selecting the appropriate settings of some effective design parameters such as the number of layers of Wells turbine fans and the intermediate distance between the fans can result in significant improvements. Moreover, simple dynamic analysis of the Wells turbine is introduced. Furthermore, this paper strives for comparing the theoretical and experimental results of the built experimental prototype.

Keywords: renewable energy, oscillating water column, multi-criteria selection, Wells turbine

Procedia PDF Downloads 162
58063 A Leader-Follower Kinematic-Based Control System for a Cable-Driven Hyper-Redundant Manipulator

Authors: Abolfazl Zaraki, Yoshikatsu Hayashi, Harry Thorpe, Vincent Strong, Gisle-Andre Larsen, William Holderbaum

Abstract:

Thanks to the high maneuverability of the cable-driven hyper-redundant manipulators (HRMs), this class of robots has shown a superior capability in highly confined and unstructured space applications. Although the large number of degrees of freedom (DOF) of HRMs enhances the motion flexibility and the robot’s reachability range, it highly increases the complexity of the kinematic configuration which makes the kinematic control problem very challenging or even impossible to solve. This paper presents our current progress achieved on the development of a kinematic-based leader-follower control system which is designed to control not only the robot’s body posture but also to control the trajectory of the robot’s movement in a semi-autonomous manner (the human operator is retained in the robot’s control loop). To obtain the forward kinematic model, the coordinate frames are established by the classical Denavit–Hartenburg (D-H) convention for a hyper-redundant serial manipulator which has a controlled cables-driven mechanism. To solve the inverse kinematics of the robot, unlike the conventional methods, a leader-follower mechanism, based on the sequential inverse kinematic, is followed. Using this mechanism, the inverse kinematic problem is solved for all sequential joints starting from the head joint to the base joint of the robot. To verify the kinematic design and simulate the robot motion, the MATLAB robotic toolbox is used. The simulation result demonstrated the promising capability of the proposed leader-follower control system in controlling the robot motion and trajectory in our confined space application.

Keywords: hyper-redundant robots, kinematic analysis, semi-autonomous control, serial manipulators

Procedia PDF Downloads 157