Pub Date : 2012-04-03DOI: 10.1109/IBCAST.2012.6177563
T. Bano, N. Sheikh, S. Manzoor, S. Khushnood
A study of the behavior of a square cylinder subjected to an upstream uniform air flow is presented. The present investigation uses commercial CFD software FLUENT 6.2.16 to simulate time-resolved flow field using constitutive relationships suitable for laminar flows. Variation of flow induced lift force coefficient is used to estimate shedding frequency and resultant mean structural vibration for the Reynolds number range of 2000-8000. Simulation results in terms of limit cycle oscillation amplitude are compared with pre-existing experimental data.
{"title":"Numerical simulation of flow past a square cylinder","authors":"T. Bano, N. Sheikh, S. Manzoor, S. Khushnood","doi":"10.1109/IBCAST.2012.6177563","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177563","url":null,"abstract":"A study of the behavior of a square cylinder subjected to an upstream uniform air flow is presented. The present investigation uses commercial CFD software FLUENT 6.2.16 to simulate time-resolved flow field using constitutive relationships suitable for laminar flows. Variation of flow induced lift force coefficient is used to estimate shedding frequency and resultant mean structural vibration for the Reynolds number range of 2000-8000. Simulation results in terms of limit cycle oscillation amplitude are compared with pre-existing experimental data.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124084015","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177534
M. A. Javed, Xu Guili, Yao Jie, Ning Li, S. Y. Shah
In this paper we present a new method for detecting moving object in infrared image sequences which contain nuisance objects and noise. The moving target detection approach is based on wavelet transform with GPU implementation. According to the features of the modulus maxima images after wavelet transform, the background clutter and noise are eliminated. The effectiveness of this new method is demonstrated by applying the resulting algorithm to infrared images containing moving targets.
{"title":"GPU based small target detection using IR images","authors":"M. A. Javed, Xu Guili, Yao Jie, Ning Li, S. Y. Shah","doi":"10.1109/IBCAST.2012.6177534","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177534","url":null,"abstract":"In this paper we present a new method for detecting moving object in infrared image sequences which contain nuisance objects and noise. The moving target detection approach is based on wavelet transform with GPU implementation. According to the features of the modulus maxima images after wavelet transform, the background clutter and noise are eliminated. The effectiveness of this new method is demonstrated by applying the resulting algorithm to infrared images containing moving targets.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126820151","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177572
S. Iqbal, M. Amin, J. Yousaf
In this paper, a circularly polarized, omnidirectional side-fed bifilar helix antenna, which does not require a ground plane is presented. The antenna has a height of less than 0.1λ and the maximum boresight gain of 1.95dB, with 3dB beamwidth of 93°. The impedance bandwidth of the antenna for VSWR≤2 (with reference to resonant input resistance of 25Ω) is 2.7%. The simulated axial ratio(AR) at the resonant frequency 860MHz is 0.9 ≤AR≤ 1.0 in the whole hemisphere except small region around the nulls. The polarization bandwidth for AR≤3dB is 34.7%. The antenna is especially useful for high speed aerodynamic bodies made of composite materials (such as UAVs) where low profile antennas are essential to reduce air resistance and/or proper metallic ground is not available for monopole-type antenna.
{"title":"Low profile circularly polarized side-fed bifilar helix antenna","authors":"S. Iqbal, M. Amin, J. Yousaf","doi":"10.1109/IBCAST.2012.6177572","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177572","url":null,"abstract":"In this paper, a circularly polarized, omnidirectional side-fed bifilar helix antenna, which does not require a ground plane is presented. The antenna has a height of less than 0.1λ and the maximum boresight gain of 1.95dB, with 3dB beamwidth of 93°. The impedance bandwidth of the antenna for VSWR≤2 (with reference to resonant input resistance of 25Ω) is 2.7%. The simulated axial ratio(AR) at the resonant frequency 860MHz is 0.9 ≤AR≤ 1.0 in the whole hemisphere except small region around the nulls. The polarization bandwidth for AR≤3dB is 34.7%. The antenna is especially useful for high speed aerodynamic bodies made of composite materials (such as UAVs) where low profile antennas are essential to reduce air resistance and/or proper metallic ground is not available for monopole-type antenna.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128025148","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177521
I. Khan, A. I. Bhatti, Q. Khan, Q. Ahmad
This paper presents various sliding mode techniques starting from a conventional first order SMC and then integral SMC, Super twisting algorithm and real twisting algorithm) for the tracking control of the lateral dynamics of an autonomous underwater vehicle (AUV). Moreover the controllability and observability analysis of the lateral dynamics is given and a Slotine observer [J, -J. E Slotine, J. K Hedrick, E. A. Misawa 1987] has also been proposed for it. Based on the simulation results a comparison of various controllers is made. The higher order SMC provides a chattering free tracking and a model free control which is robust to parametric variations.
从传统的一阶滑模控制到积分滑模控制、超扭转算法和实扭转算法，提出了用于自主水下航行器(AUV)横向动力学跟踪控制的各种滑模技术。此外，给出了横向动力学的可控性和可观测性分析，并给出了一个slotime观测器[J]。E Slotine, J. K . Hedrick, E. A. Misawa 1987]也被提出。在仿真结果的基础上，对各种控制器进行了比较。高阶SMC提供无抖振跟踪和无模型控制，对参数变化具有鲁棒性。
{"title":"Sliding mode control of lateral dynamics of an AUV","authors":"I. Khan, A. I. Bhatti, Q. Khan, Q. Ahmad","doi":"10.1109/IBCAST.2012.6177521","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177521","url":null,"abstract":"This paper presents various sliding mode techniques starting from a conventional first order SMC and then integral SMC, Super twisting algorithm and real twisting algorithm) for the tracking control of the lateral dynamics of an autonomous underwater vehicle (AUV). Moreover the controllability and observability analysis of the lateral dynamics is given and a Slotine observer [J, -J. E Slotine, J. K Hedrick, E. A. Misawa 1987] has also been proposed for it. Based on the simulation results a comparison of various controllers is made. The higher order SMC provides a chattering free tracking and a model free control which is robust to parametric variations.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"297 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133548431","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177588
H. A. Mirza, I. Shah, F. Abbasi, M. Shafiq
Beamformer is an indispensible part of any phased array system. Analog beamformer is the simpler method where the individual signals received from array of antennas are co-phased and summed to maximize the signal reception. The co-phasing is achieved through data independent weights which are predefined as per direction of arrival. These weights are applied to the analog phase shifter IC, which produces a set of phases in order to compensate the directional phase shifts. Signals are then combined with a power combiner. For realistic demonstration, signals from different locations are transmitted through a transmitter with a horn antenna. The beamformer successfully enhances the signal from the direction of interest.
{"title":"Hardware implementation of analog beamformer for phased array radar (PAR)","authors":"H. A. Mirza, I. Shah, F. Abbasi, M. Shafiq","doi":"10.1109/IBCAST.2012.6177588","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177588","url":null,"abstract":"Beamformer is an indispensible part of any phased array system. Analog beamformer is the simpler method where the individual signals received from array of antennas are co-phased and summed to maximize the signal reception. The co-phasing is achieved through data independent weights which are predefined as per direction of arrival. These weights are applied to the analog phase shifter IC, which produces a set of phases in order to compensate the directional phase shifts. Signals are then combined with a power combiner. For realistic demonstration, signals from different locations are transmitted through a transmitter with a horn antenna. The beamformer successfully enhances the signal from the direction of interest.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131673980","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177559
N. Durrani
The present study is focused to evaluate the accuracy of the Detached-Eddy Simulation (DES), Delayed Detached-Eddy Simulation (DDES) and Reynolds Averaged Navier-Stokes (RANS) equations for a mild separation case. An in-house code dynamic grid detached eddy simulation `DG-DES' is used. The modeled turbulent Reynolds stresses are computed as a reference quantity. The flow around Aerospatiale A-airfoil at maximum lift with angle of attack α=13.3° and at a Reynolds number of 2× 106 is taken as the test case. The detailed experimental data for this case is available in the open literature. The computed turbulent Reynolds stresses from DES are lower than RANS within the boundary layer at the leading edge of the suction side. It is argued to be due to the premature switching to less dissipative LES mode within boundary layer. The DDES gives comparable values to RANS, as an expected outcome. It is observed that for the cases with the mild separation, although DDES works in correct fashion in line with the basic concept of treating the whole of the boundary layer in RANS mode. However, the original DES may perform better than the DDES due to lower dissipation characteristics. The DES results on the suction side in the wake-region are encouraging and comparatively better than DDES, despite its switching problem.
{"title":"Comparison of modelled reynolds stresses for mild separation using RANS, DES and DDES schemes","authors":"N. Durrani","doi":"10.1109/IBCAST.2012.6177559","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177559","url":null,"abstract":"The present study is focused to evaluate the accuracy of the Detached-Eddy Simulation (DES), Delayed Detached-Eddy Simulation (DDES) and Reynolds Averaged Navier-Stokes (RANS) equations for a mild separation case. An in-house code dynamic grid detached eddy simulation `DG-DES' is used. The modeled turbulent Reynolds stresses are computed as a reference quantity. The flow around Aerospatiale A-airfoil at maximum lift with angle of attack α=13.3° and at a Reynolds number of 2× 106 is taken as the test case. The detailed experimental data for this case is available in the open literature. The computed turbulent Reynolds stresses from DES are lower than RANS within the boundary layer at the leading edge of the suction side. It is argued to be due to the premature switching to less dissipative LES mode within boundary layer. The DDES gives comparable values to RANS, as an expected outcome. It is observed that for the cases with the mild separation, although DDES works in correct fashion in line with the basic concept of treating the whole of the boundary layer in RANS mode. However, the original DES may perform better than the DDES due to lower dissipation characteristics. The DES results on the suction side in the wake-region are encouraging and comparatively better than DDES, despite its switching problem.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125818008","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177551
Imran Mahmood, Mansoor-ul-Haq, H. Rafiuddin, M. Rafique
Supersonic flow over a compression expansion corner is simulatednumerically. Three-dimensional Navier-Stokes equations have been solvedovercompression expansion corner for validation of in- house three dimensional Navier stokes code. Steger and warming flux vector splitting scheme has been used. Simulation captures all the features of complex flow problem including formation of oblique shock, expansion wave and their reflection and interaction. The results compare very well with the analytical data.
{"title":"Numerical simulation of supersonic flow over compression expansion corner using 3-D NS code","authors":"Imran Mahmood, Mansoor-ul-Haq, H. Rafiuddin, M. Rafique","doi":"10.1109/IBCAST.2012.6177551","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177551","url":null,"abstract":"Supersonic flow over a compression expansion corner is simulatednumerically. Three-dimensional Navier-Stokes equations have been solvedovercompression expansion corner for validation of in- house three dimensional Navier stokes code. Steger and warming flux vector splitting scheme has been used. Simulation captures all the features of complex flow problem including formation of oblique shock, expansion wave and their reflection and interaction. The results compare very well with the analytical data.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116909463","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177593
A. Mumtaz, M. K. Islam, A. Hassan, O. Khalid
We have presented a method for optical generation of doublet and triplet and presented a complete DWDM ring on single fiber with UWB generation for uplink signal. This UWB system can support 3 rings. Optical Add Drop Multiplexers are used at each UWB node to drop and insert the required wavelengths. Simulation of Self-phase modulation is done to study the effects on UWB transmission and method has been proposed to minimize the effects.
{"title":"Ultra Wide Band Radio DWDM rings with photonic UWB pulse generation and transmission in presence of non-linearities","authors":"A. Mumtaz, M. K. Islam, A. Hassan, O. Khalid","doi":"10.1109/IBCAST.2012.6177593","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177593","url":null,"abstract":"We have presented a method for optical generation of doublet and triplet and presented a complete DWDM ring on single fiber with UWB generation for uplink signal. This UWB system can support 3 rings. Optical Add Drop Multiplexers are used at each UWB node to drop and insert the required wavelengths. Simulation of Self-phase modulation is done to study the effects on UWB transmission and method has been proposed to minimize the effects.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"612 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131735322","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177522
Abdul Manan Khan, Amir Iqbal Bhatti, Sami-ud-Din, Q. Khan
This paper presents an application of static and dynamic sliding mode control of ball and beam system. Conventional PID controllers use incomplete simplified models and are mostly designed for linear systems. Although, some PID controllers are designed for nonlinear system but they are using simplified incomplete model which do not cater for matched disturbances. Our proposed control laws using static & dynamic sliding mode control use complete nonlinear system without model approximation. Moreover, static sliding mode control (SSMC) caters for matched disturbance rejection as well. There is an inherent issue of chattering with static sliding mode control (SSMC). However, dynamics sliding mode control (DSMC) counter it well. DSMC is not only equally effective when it comes to matched disturbance rejection but also removes chattering as well. In the end detailed comparative analysis is presented and experimental results confirm the superiority of DSMC.
{"title":"Static & dynamic sliding mode control of ball and beam system","authors":"Abdul Manan Khan, Amir Iqbal Bhatti, Sami-ud-Din, Q. Khan","doi":"10.1109/IBCAST.2012.6177522","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177522","url":null,"abstract":"This paper presents an application of static and dynamic sliding mode control of ball and beam system. Conventional PID controllers use incomplete simplified models and are mostly designed for linear systems. Although, some PID controllers are designed for nonlinear system but they are using simplified incomplete model which do not cater for matched disturbances. Our proposed control laws using static & dynamic sliding mode control use complete nonlinear system without model approximation. Moreover, static sliding mode control (SSMC) caters for matched disturbance rejection as well. There is an inherent issue of chattering with static sliding mode control (SSMC). However, dynamics sliding mode control (DSMC) counter it well. DSMC is not only equally effective when it comes to matched disturbance rejection but also removes chattering as well. In the end detailed comparative analysis is presented and experimental results confirm the superiority of DSMC.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131330384","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 : 2012-04-03DOI: 10.1109/IBCAST.2012.6177580
M. Latif, F. Shafiq, M. Shafique, N. Naseer
This paper describes the design and realization of 7th order Ku-band bandpass filter. This filter is a part of pre-filter required for desired frequency spectrum selection in a communication satellite. The filter is realized with rectangular waveguide WR75 in TE101 mode; because it can give optimum size with high unloaded quality factor and wide spurious free window. The engineering model of the filter is realized with Aluminum material. Temperature variations cause the volumetric thermal expansion of the filter and the equivalent linear frequency drift is incorporated at the synthesis stage of the filter. Tolerance analysis of the filter is also performed to compensate the manufacturing errors. Semi-miniaturized SMA to waveguide transformers were also developed for testing of the filter. Filter is synthesized using indigenously developed software tool. Utilizing the coupling matrix; each inter-resonator coupling iris and input/output iris is designed separately. There is a good overlap of the tested and the simulated responses.
{"title":"Design & realization of direct coupled Ku-band waveguide iris filter using coupling matrix model","authors":"M. Latif, F. Shafiq, M. Shafique, N. Naseer","doi":"10.1109/IBCAST.2012.6177580","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177580","url":null,"abstract":"This paper describes the design and realization of 7th order Ku-band bandpass filter. This filter is a part of pre-filter required for desired frequency spectrum selection in a communication satellite. The filter is realized with rectangular waveguide WR75 in TE101 mode; because it can give optimum size with high unloaded quality factor and wide spurious free window. The engineering model of the filter is realized with Aluminum material. Temperature variations cause the volumetric thermal expansion of the filter and the equivalent linear frequency drift is incorporated at the synthesis stage of the filter. Tolerance analysis of the filter is also performed to compensate the manufacturing errors. Semi-miniaturized SMA to waveguide transformers were also developed for testing of the filter. Filter is synthesized using indigenously developed software tool. Utilizing the coupling matrix; each inter-resonator coupling iris and input/output iris is designed separately. There is a good overlap of the tested and the simulated responses.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124525564","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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