Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667247
Zainab Akhtar, Adnan Nisar, M. T. Hamayun
Unmanned air vehicles (UAVs) have received tremendous importance because of their civil, military, industrial, agricultural and security etc. applications. As compared to terrestrial robots, UAVs have to face stronger aerodynamic as well as gravitational forces which effect the dynamics of these flying structures. The control and estimation of unavailable plant states in UAVs is a challenging task due to their nonlinear dynamics in the presence of external uncertainties like air load and noise effects. Practically, external aerodynamic disturbances and sensor noise can alter the desired performance of the aerial robots leading to instability and loss of control of UAVs. Information of all plant states is important for better control and navigation of UAVs. In this paper it is assumed that all plant states are not available, therefore, nonlinear observer design techniques are used to estimate unavailable states of quadrotor plant with least error. The designed nonlinear observer’s results are compared in simulations in the presence of external disturbance and sensor noise. Sliding mode observers implemented in this paper exhibit the property of finite time convergence of error dynamics both with and without disturbances and noise.
{"title":"Nonlinear Sliding Mode State Estimation Techniques for UAV Application","authors":"Zainab Akhtar, Adnan Nisar, M. T. Hamayun","doi":"10.1109/IBCAST.2019.8667247","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667247","url":null,"abstract":"Unmanned air vehicles (UAVs) have received tremendous importance because of their civil, military, industrial, agricultural and security etc. applications. As compared to terrestrial robots, UAVs have to face stronger aerodynamic as well as gravitational forces which effect the dynamics of these flying structures. The control and estimation of unavailable plant states in UAVs is a challenging task due to their nonlinear dynamics in the presence of external uncertainties like air load and noise effects. Practically, external aerodynamic disturbances and sensor noise can alter the desired performance of the aerial robots leading to instability and loss of control of UAVs. Information of all plant states is important for better control and navigation of UAVs. In this paper it is assumed that all plant states are not available, therefore, nonlinear observer design techniques are used to estimate unavailable states of quadrotor plant with least error. The designed nonlinear observer’s results are compared in simulations in the presence of external disturbance and sensor noise. Sliding mode observers implemented in this paper exhibit the property of finite time convergence of error dynamics both with and without disturbances and noise.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127486285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667238
W. A. Malik, W. M. Abdulkawi, A. A. Sheta, Naif F. Alzakari
The design of a wideband 6 Watts LDMOS based balanced power amplifier (PA) is presented. The proposed balanced PA covers a frequency band of 500 MHz (1.2-1.7 GHz) with 1.5 GHz as a center frequency. The single ended PA achieves a gain of 10.9 dB. The T-network topology is adopted to design the input and output matching circuits. The PA is fabricated on FR4 with 1.5 mm thickness. The measured results show a very good agreement with the simulated results. The balanced PA is formed by duplicating the single PA along with the quadrature coupler at its input and output to split and combine the signals respectively. The performance of the balanced PA makes it suitable to be incorporated in any recent and future wireless communication systems.
{"title":"A 6 Watts LDMOS Wideband Balanced Power Amplifier","authors":"W. A. Malik, W. M. Abdulkawi, A. A. Sheta, Naif F. Alzakari","doi":"10.1109/IBCAST.2019.8667238","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667238","url":null,"abstract":"The design of a wideband 6 Watts LDMOS based balanced power amplifier (PA) is presented. The proposed balanced PA covers a frequency band of 500 MHz (1.2-1.7 GHz) with 1.5 GHz as a center frequency. The single ended PA achieves a gain of 10.9 dB. The T-network topology is adopted to design the input and output matching circuits. The PA is fabricated on FR4 with 1.5 mm thickness. The measured results show a very good agreement with the simulated results. The balanced PA is formed by duplicating the single PA along with the quadrature coupler at its input and output to split and combine the signals respectively. The performance of the balanced PA makes it suitable to be incorporated in any recent and future wireless communication systems.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131987543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667193
T. Shams, Syed Irtiza Ali Shah, Sara Khushbash, M. Ahmad
Aerodynamic performance and stability parameters of high wing piston engine aircraft were evaluated using Computational Fluid Dynamics and validated against wind tunnel test and analytical solution. The results were calculated at various angles of attack and angles of sideslip at standard sea level conditions and at 121 Kts. Aircraft geometry was scanned with scanner and meshing was carried out using hexagonal mesh elements with growth ratio of 1.2. SA turbulence model was used in commercially available software Fluent®. Boundary layer effects were modeled using prism elements with y+ value of 35 and standard wall functions. Convergence was achieved in around 12000 iterations using 6.34 million volume mesh. It was found that gradient of pitching moment coefficient with angle of attack was -0.003 rad-1 which showed longitudinal stable behavior. However, the trim angle of attack was obtained as -2o therefore aircraft needs to be trimmed at positive angle of attack for steady and level flight. It is also found that tendency of instability is caused mainly by swirl effect of propeller. Rolling and yawing moment coefficients showed that aircraft not only underwent positive yaw but also rolled towards right. This yaw-roll coupling was computationally captured, however magnitude of yaw-roll coupling was found to be very small due to the swept forward wings and high wing configuration. Wind tunnel tests were carried out at 121Kts and lift and drag coefficients were compared with CFD results. Wind tunnel tests over predicted coefficient of lift at all angles of attack, however it under predicted coefficient of drag at all angles of attack. Most probable cause of this deviation seems to be more turbulence and vibration level of wind tunnel. The Zero lift drag coefficient of aircraft was found to be higher as compared to other similar aircraft like Cessna 172.
{"title":"Evaluation of Aerodynamic and Stability Performance Parameters of High Wing Piston Engine Aircraft","authors":"T. Shams, Syed Irtiza Ali Shah, Sara Khushbash, M. Ahmad","doi":"10.1109/IBCAST.2019.8667193","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667193","url":null,"abstract":"Aerodynamic performance and stability parameters of high wing piston engine aircraft were evaluated using Computational Fluid Dynamics and validated against wind tunnel test and analytical solution. The results were calculated at various angles of attack and angles of sideslip at standard sea level conditions and at 121 Kts. Aircraft geometry was scanned with scanner and meshing was carried out using hexagonal mesh elements with growth ratio of 1.2. SA turbulence model was used in commercially available software Fluent®. Boundary layer effects were modeled using prism elements with y+ value of 35 and standard wall functions. Convergence was achieved in around 12000 iterations using 6.34 million volume mesh. It was found that gradient of pitching moment coefficient with angle of attack was -0.003 rad-1 which showed longitudinal stable behavior. However, the trim angle of attack was obtained as -2o therefore aircraft needs to be trimmed at positive angle of attack for steady and level flight. It is also found that tendency of instability is caused mainly by swirl effect of propeller. Rolling and yawing moment coefficients showed that aircraft not only underwent positive yaw but also rolled towards right. This yaw-roll coupling was computationally captured, however magnitude of yaw-roll coupling was found to be very small due to the swept forward wings and high wing configuration. Wind tunnel tests were carried out at 121Kts and lift and drag coefficients were compared with CFD results. Wind tunnel tests over predicted coefficient of lift at all angles of attack, however it under predicted coefficient of drag at all angles of attack. Most probable cause of this deviation seems to be more turbulence and vibration level of wind tunnel. The Zero lift drag coefficient of aircraft was found to be higher as compared to other similar aircraft like Cessna 172.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121213735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667263
N. Kashif, M. Dou, Dongdong Zhao
Conventional model predictive control method uses one optimal voltage vector during a control period. It causes higher flux and torque ripples and harmonics. It also heavily relies on system parameters which no more remain constant with the passage of time due to changes in temperature. This paper proposes an improved version of finite control set model predictive current control method with duty cycle. Introduction of duty cycle allows the freedom to incorporate a zero voltage vector with optimal one for a calculated fraction of control period. In order to make model predictive control method independent of system parameters, emf estimation is introduced which takes into account voltage and current vectors from previous control intervals. Simulations have been carried out to verify the effectiveness of proposed methodology.
{"title":"Improved Model Predictive Current Control with Duty Cycle for Permanent Magnet Synchronous Motor Drives","authors":"N. Kashif, M. Dou, Dongdong Zhao","doi":"10.1109/IBCAST.2019.8667263","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667263","url":null,"abstract":"Conventional model predictive control method uses one optimal voltage vector during a control period. It causes higher flux and torque ripples and harmonics. It also heavily relies on system parameters which no more remain constant with the passage of time due to changes in temperature. This paper proposes an improved version of finite control set model predictive current control method with duty cycle. Introduction of duty cycle allows the freedom to incorporate a zero voltage vector with optimal one for a calculated fraction of control period. In order to make model predictive control method independent of system parameters, emf estimation is introduced which takes into account voltage and current vectors from previous control intervals. Simulations have been carried out to verify the effectiveness of proposed methodology.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116928181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667131
S. Anwar, Tahira Batool, Muhammad Majid
Polygraph based detection systems have been used for performing guilty knowledge test (GKT) over a long period of time. More recently the advances in medical imaging techniques have resulted in a better understanding of brain activity. These techniques (e.g. functional magnetic resonance imaging) have allowed researchers to generate applications that are based on the enhanced understanding of brain function. Detection of concealed information using brain activity is explored in this study as a better alternative to a Polygraph. Electroencephalography (EEG) allows decoding brain signals with a higher temporal resolution by applying smart signal processing techniques. In this work a commercial off the shelf wearable EEG headset is used to record brain signals in an information concealment testing environment. Although the use of such setup restricts the number of EEG channels available to the detection algorithm, but it provides portability and ease of use when compared to clinical EEG setup. The proposed algorithm is designed to give optimum results in terms of accuracy and computation time with emphasis on an easily deployable system.
{"title":"Event Related Potential (ERP) based Lie Detection using a Wearable EEG headset","authors":"S. Anwar, Tahira Batool, Muhammad Majid","doi":"10.1109/IBCAST.2019.8667131","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667131","url":null,"abstract":"Polygraph based detection systems have been used for performing guilty knowledge test (GKT) over a long period of time. More recently the advances in medical imaging techniques have resulted in a better understanding of brain activity. These techniques (e.g. functional magnetic resonance imaging) have allowed researchers to generate applications that are based on the enhanced understanding of brain function. Detection of concealed information using brain activity is explored in this study as a better alternative to a Polygraph. Electroencephalography (EEG) allows decoding brain signals with a higher temporal resolution by applying smart signal processing techniques. In this work a commercial off the shelf wearable EEG headset is used to record brain signals in an information concealment testing environment. Although the use of such setup restricts the number of EEG channels available to the detection algorithm, but it provides portability and ease of use when compared to clinical EEG setup. The proposed algorithm is designed to give optimum results in terms of accuracy and computation time with emphasis on an easily deployable system.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127577594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667148
S. H. Shah, S. G. Khan, I. Haq, Kamran Shah, A. Abid
The existing robotic walk assist devices (RWAD) are not affordable for everyone particularly in low income countries like Pakistan. In addition, convincing people to adopt such devices is somehow challenging due to lack of trust, dependability and cultural constraints. Safety of the users is also a major concern. Many researchers are currently working in this area to come up with better mechanical design along with safe and trust worthy control techniques. Some aspects of safety can be addressed with the help of compliance (low-stiffness and flexibility) control. Compliance(low stiffness) control will make RWAD more user friendly by limiting the forces RWAD applied on the human user. In this paper a model reference compliance control scheme is suggested for a robotic walk assist device based on integral sliding mode control (ISMC) coupled with a dynamic model based feedback linearization controller. Joint torques feedback from the knee and hip joints are used to make the robotic walk assist device compliant via ISMC. A mass-spring-damper system is used as a compliant reference model. Simulation results are presented to show the effectiveness of the suggested scheme.
{"title":"COMPLIANCE CONTROL OF ROBOTIC WALK ASSIST DEVICE VIA INTEGRAL SLIDING MODE CONTROL","authors":"S. H. Shah, S. G. Khan, I. Haq, Kamran Shah, A. Abid","doi":"10.1109/IBCAST.2019.8667148","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667148","url":null,"abstract":"The existing robotic walk assist devices (RWAD) are not affordable for everyone particularly in low income countries like Pakistan. In addition, convincing people to adopt such devices is somehow challenging due to lack of trust, dependability and cultural constraints. Safety of the users is also a major concern. Many researchers are currently working in this area to come up with better mechanical design along with safe and trust worthy control techniques. Some aspects of safety can be addressed with the help of compliance (low-stiffness and flexibility) control. Compliance(low stiffness) control will make RWAD more user friendly by limiting the forces RWAD applied on the human user. In this paper a model reference compliance control scheme is suggested for a robotic walk assist device based on integral sliding mode control (ISMC) coupled with a dynamic model based feedback linearization controller. Joint torques feedback from the knee and hip joints are used to make the robotic walk assist device compliant via ISMC. A mass-spring-damper system is used as a compliant reference model. Simulation results are presented to show the effectiveness of the suggested scheme.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130447163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667227
J. Iqbal, Rehan Khan, F. Ahmed, H. I. Hussain
Ocean seems to be silent but actually it is not so. It is always enriched with a background noise known as ambient noise caused by wind, heat, turbulence and some other activities and natural phenomenon. This noise poses considerable hindrances in undersea acoustic communication which is so essential for Oceanographic Monitoring. Oceanographic monitoring covers numerous undersea applications like oceanographic data collection, pollution monitoring, offshore undersea exploration, detect climate changes, seismic monitoring, disaster prevention etc. Exploring the latest statistical characterization trends of Indian Ocean ambient noise in highly spatiotemporal sea environment, we put forward a different approach based on Monte-Carlo simulation method to explore, analyze and verify the empirical data / observations of deep sea ambient noise against its well-known standard Gaussian model in both narrowband and broadband frequency spectrums. Results of variances reveal that the actual ambient noise observations are in very close agreement with the predicted standard Gaussian model in most of the selected broadband frequency spectrums except the narrowband frequency spectrum in which the data summary statistics is numerically found to be non-symmetric. This exception in results has a profound impact on the understanding and behavioral modeling of deep sea ambient noise which is to be analyzed specifically in the narrowband frequency spectrum.
{"title":"A Comparative Analysis of the Latest Statistical Characterization Trends of Narrowband & Broadband Frequency Spectrum of Deep Sea Ambient Noise Using Monte Carlo Simulation Method","authors":"J. Iqbal, Rehan Khan, F. Ahmed, H. I. Hussain","doi":"10.1109/IBCAST.2019.8667227","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667227","url":null,"abstract":"Ocean seems to be silent but actually it is not so. It is always enriched with a background noise known as ambient noise caused by wind, heat, turbulence and some other activities and natural phenomenon. This noise poses considerable hindrances in undersea acoustic communication which is so essential for Oceanographic Monitoring. Oceanographic monitoring covers numerous undersea applications like oceanographic data collection, pollution monitoring, offshore undersea exploration, detect climate changes, seismic monitoring, disaster prevention etc. Exploring the latest statistical characterization trends of Indian Ocean ambient noise in highly spatiotemporal sea environment, we put forward a different approach based on Monte-Carlo simulation method to explore, analyze and verify the empirical data / observations of deep sea ambient noise against its well-known standard Gaussian model in both narrowband and broadband frequency spectrums. Results of variances reveal that the actual ambient noise observations are in very close agreement with the predicted standard Gaussian model in most of the selected broadband frequency spectrums except the narrowband frequency spectrum in which the data summary statistics is numerically found to be non-symmetric. This exception in results has a profound impact on the understanding and behavioral modeling of deep sea ambient noise which is to be analyzed specifically in the narrowband frequency spectrum.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"158 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130993655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667240
Farhana Hasham, M. Mujahid
First generation membranes developed were non-resorbable and required a second surgical procedure for their removal. In order to overcome this obstacle biodegradable, resorb-able composite films were developed which may also assist in bone healing. In this paper, composite films comprising varying amounts of nano hydroxyapatite (0.5-30%) in chitosan (biopolymer) matrix were prepared by solvent casting method. Composite films were further characterized and mechanical properties were evaluated. Results showed increased strength and stability until 10-wt% HA beyond which properties declined. Immersion of composite films in SBF solution confirmed their bioactivity. This study concludes composite films with 10-wt% HA as a potential candidate for barrier films in the field of orthopedics and dentistry.
{"title":"Development of Resorb-able Nano Composite Films for Orthodontic Applications","authors":"Farhana Hasham, M. Mujahid","doi":"10.1109/IBCAST.2019.8667240","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667240","url":null,"abstract":"First generation membranes developed were non-resorbable and required a second surgical procedure for their removal. In order to overcome this obstacle biodegradable, resorb-able composite films were developed which may also assist in bone healing. In this paper, composite films comprising varying amounts of nano hydroxyapatite (0.5-30%) in chitosan (biopolymer) matrix were prepared by solvent casting method. Composite films were further characterized and mechanical properties were evaluated. Results showed increased strength and stability until 10-wt% HA beyond which properties declined. Immersion of composite films in SBF solution confirmed their bioactivity. This study concludes composite films with 10-wt% HA as a potential candidate for barrier films in the field of orthopedics and dentistry.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132198286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667209
Sohail Ahmed, F. Siddique, M. Waqas, M. Hasan, S. Rehman
In digital communication system and signal processing, Viterbi algorithm is an optimal solution for error detection and correction. Viterbi algorithm finds the most likely closet sequence in distance to the received sequence of noisy symbol. Performance and hardware implementing complexity of Viterbi algorithm is mainly depend on constraint length. Larger constraint length requires more memory but provides lower Bit Error rate (BER) without increasing the signal power. In this paper, Viterbi algorithm is analyzed for BPSK modulated convolutional encoded data over AWGN channel on different constraint lengths. Trace back and Trace forward methods are also reviewed for better memory utilization and computational complexity.
{"title":"Viterbi Algorithm Performance Analysis for Different Constraint Length","authors":"Sohail Ahmed, F. Siddique, M. Waqas, M. Hasan, S. Rehman","doi":"10.1109/IBCAST.2019.8667209","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667209","url":null,"abstract":"In digital communication system and signal processing, Viterbi algorithm is an optimal solution for error detection and correction. Viterbi algorithm finds the most likely closet sequence in distance to the received sequence of noisy symbol. Performance and hardware implementing complexity of Viterbi algorithm is mainly depend on constraint length. Larger constraint length requires more memory but provides lower Bit Error rate (BER) without increasing the signal power. In this paper, Viterbi algorithm is analyzed for BPSK modulated convolutional encoded data over AWGN channel on different constraint lengths. Trace back and Trace forward methods are also reviewed for better memory utilization and computational complexity.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128415334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1109/IBCAST.2019.8667216
A. Mustafa, H. Saeed
Response during energy absorption of a tube system is the key for its application in structures under dynamic loading. An ideal energy absorber should behave with a low peak force, high mean crushing force and with a smooth force displacement curve while under dynamic loading. In this particular study, a bunch of metallic 3-step stepped-tubes with ascending number of stepped-tubes in different configurations are placed inside a metallic thin-walled tube and are numerically investigated for its energy absorption characteristics under dynamic axial loads. Stepped-tubes can absorb energy with progressive failure as per specific need of the design but their geometry parameters influence their performance. One of the initial proposed configurations with five stepped-tubes arrangement is further investigated for changing geometry of stepped-tube and sensitivity of energy absorption characteristics with changed geometry are studied. Deformation modes and different energy absorption parameters such as peak value of crushing force, specific energy absorption, mean crushing force and crush force efficiency are plotted for all of the configurations. Results are compared with published numerical and experimental results for the impact of the proposed configurations on energy absorption capability.
{"title":"Evaluation of Crashworthiness Parameters of Metallic Tubes with Multiple Inner Step Tubes Arrangements","authors":"A. Mustafa, H. Saeed","doi":"10.1109/IBCAST.2019.8667216","DOIUrl":"https://doi.org/10.1109/IBCAST.2019.8667216","url":null,"abstract":"Response during energy absorption of a tube system is the key for its application in structures under dynamic loading. An ideal energy absorber should behave with a low peak force, high mean crushing force and with a smooth force displacement curve while under dynamic loading. In this particular study, a bunch of metallic 3-step stepped-tubes with ascending number of stepped-tubes in different configurations are placed inside a metallic thin-walled tube and are numerically investigated for its energy absorption characteristics under dynamic axial loads. Stepped-tubes can absorb energy with progressive failure as per specific need of the design but their geometry parameters influence their performance. One of the initial proposed configurations with five stepped-tubes arrangement is further investigated for changing geometry of stepped-tube and sensitivity of energy absorption characteristics with changed geometry are studied. Deformation modes and different energy absorption parameters such as peak value of crushing force, specific energy absorption, mean crushing force and crush force efficiency are plotted for all of the configurations. Results are compared with published numerical and experimental results for the impact of the proposed configurations on energy absorption capability.","PeriodicalId":335329,"journal":{"name":"2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134354176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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