Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)最新文献

{"title":"On tuning parameter selection of lasso-type methods - a monte carlo study","authors":"S. Chand","doi":"10.1109/IBCAST.2012.6177542","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177542","url":null,"abstract":"In regression analysis, variable selection is a challenging task. Over the last decade, the lasso-type methods have become popular method for variable selection due to their property of shrinking some of the model coefficients to exactly zero. Theory says that lasso-type methods are able to do consistent variable selection but it is hard to achieve this property in practice. This consistent variable selection highly depends on the right choice of the tuning parameter. In this paper, we show that selection of tuning parameter by cross validation almost always fail to achieve consistent variable selection. We have also shown that lasso-type methods with a BIC-type tuning parameter selector, under certain conditions, can do the consistent variable selection. We have also made a novel suggestion for choosing the value of Cn, a weight on estimated model size, in BIC. Our results show that with this choice of Cn, the lasso-type methods can do consistent variable selection.In regression analysis, variable selection is a challenging task. Over the last decade, the lasso-type methods have become popular method for variable selection due to their property of shrinking some of the model coefficients to exactly zero. Theory says that lasso-type methods are able to do consistent variable selection but it is hard to achieve this property in practice. This consistent variable selection highly depends on the right choice of the tuning parameter. In this paper, we show that selection of tuning parameter by cross validation almost always fail to achieve consistent variable selection. We have also shown that lasso-type methods with a BIC-type tuning parameter selector, under certain conditions, can do the consistent variable selection. We have also made a novel suggestion for choosing the value of Cn, a weight on estimated model size, in BIC. Our results show that with this choice of Cn, the lasso-type methods can do consistent variable selection.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"126 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":"125044430","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}

{"title":"Multichannel blind image deconvolution","authors":"U. Javed, Muhammad Mohsin Riaz, Tanveer Ahmad Cheema","doi":"10.1109/IBCAST.2012.6177535","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177535","url":null,"abstract":"A new method has been proposed for performing multichannel blind image deconvolution. We consider the image deconvolution problem when limited information about the Point Spread Function (PSF) is available and the original image is of sparse nature. It is assumed that the original image is corrupted by a degradation function (i.e. PSF) and an Additive White Gaussian Noise. The restoration has been performed by an iterative algorithm which not only retrieves the original image but also successfully restores the unknown PSF. A comparison between the existing methods and proposed technique has been carried out. The simulation results show the efficiency and effectiveness of proposed method over existing techniques.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"97 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":"127143333","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}

{"title":"Flow controlling on low pressure turbine using passive methods","authors":"M. A. Chishty, H. Hamdani, K. Parvez","doi":"10.1109/IBCAST.2012.6177571","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177571","url":null,"abstract":"Flow control in low pressure turbine using passive devices is efficient technique to raise the efficiency of engine. In this study T106A LP Turbine geometry is used for controlling the flow separation using passive device. A lot of work is done for flow controlling using different kind of passive devices like dimples, bumps, riblets etc. Work on the backward step geometry for controlling the flow separation is not done effectively. Fine structured mesh is created with boundary layer (y + <; 1) an unstructured meshing in the rest of the domain. Unsteady RANS are solved using the Gamma-Theta Model Transitional Model for capturing the laminar separation bubble. In this study a smooth backward step of different height to length ratios (h/1) are applied on the 65% axial chord length for the reduction of loss coefficient which is another way to specify the efficiency of turbine using pressure values. After specifying the best h/1 ratio at 65% axial chord where the losses are minimum, this specific h/1 ratio step is shifted at different axial locations to And out the optimal location where the maximum losses are reduced. By making the coefficient of pressure plots and boundary layer profiles, it has been confirmed that backward step completely control the laminar separation bubble and also reduce the loss coefficient.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"42 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":"115214136","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}

{"title":"Development of 1553 mux bus simulation analysis algorithm","authors":"A. Hussain, A. Khalil, A. Abbas","doi":"10.1109/IBCAST.2012.6177587","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177587","url":null,"abstract":"MIL-STD-1553 is a protocol for a communication network, the life-line of aircrafts, space vehicles and unmanned aerial vehicles (UAVs) etc., on which the command and control computer and all the embedded Avionics subsystems of the platform are interconnected. The 1553 system integrator has to ensure that the defined limits of the 1553 standard for maximum bus loading and delay ratios are met for all the messages (in thousands) travelling on the data bus. The ICD (interface control document) of the individual subsystems are set/modified for maximum delay time (MDT)/refresh rate (RR) or message size (word count) of the messages on the basis of an analysis to make the communication network free from overload. This analysis defines the MDT/RR and word count of all the messages of the overall communication system resulting in an optimal communication system design. In this paper we have developed a novel algorithm/tool i.e. Mux Bus Simulation analysis tool (MUSAT) that analyzes the data bus loading and its delay ratio by simulating the real time communication operation of the application layer of the mission management computer (MMC) of the 1553 network. A novel data bus static optimization algorithm (DBSOA) is developed which schedules all the data words of the messages of any given Avionics system ICD into a number of minor frames of a major frame of data such that all the minor frames are nearly uniformly loaded. The developed tool (MUSAT) is based on the improved version of the DBSOA called ISBC (improved static bus control) algorithm that loads the messages of all the sub systems from the scheduled block list of the DBSOA asynchronously and dynamically depending upon their refresh rates. Complete data bus loading and delay ratio of all the messages are found for a specified overall time length comprising of 100s of major frames. With this type of message scheduling and loading, the performance of the 1553 communication network improves considerably i.e. the bus loading and delay ratio are optimal for the selected refresh rates /MDTs of the messages of the complete ICD. The 1553 communication network designed on the basis of this analysis fulfills all the requirements of MIL-STD-1553, and is free from communication overload. Furthermore, the ISBC algorithm makes possible the minimum number of iterations during the 1553 network avionics hardware integration cycle that result in the optimization of the communication system design.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"49 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":"121209531","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}

{"title":"Design and realization of 10th order (10-4-4) self equalized dual mode waveguide channel filter","authors":"M. Latif, A. U. Salfi","doi":"10.1109/IBCAST.2012.6177578","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177578","url":null,"abstract":"This paper presents the synthesis and realization of 10th order (10-4-4) self equalized dual mode waveguide channel filter in C-band. The filter is realized with circular cavities in TE111 mode for optimum size and very high unloaded quality factor. The filter is designed in dual mode configuration; where one physical cavity represents two electrical resonators; so 10th order filter is realized with five physical resonant cavities. The equivalent linear frequency drift (for temperate variations) is incorporated at the synthesis stage of the filter. The engineering model of the filter is manufactured using aluminum metal. The filter is synthesized using indigenously developed software tool. Eight finite transmission zeros are incorporated; four transmission zeros are for out of band rejection and a complex quad of transmission zeros is for group delay equalization. The filter is realized with quasi Pfitzenmaier topology having better input/output isolation and meeting unusual layout restrictions. A full wave model of the filter is simulated in software tool and an efficient method for finding approximate lengths of tuning screws is proposed. This method can be utilized in computer aided tuning (CAT) of waveguide filters. The results of the manufactured engineering model of the filter show good agreement with the theoretical/simulation results.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"19 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":"123819385","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}

{"title":"Simulation of 3D flow field of RPVC in twin-screw extrusion under wall slip conditions","authors":"Jinnan Chen, Y. Cao","doi":"10.1109/IBCAST.2012.6177540","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177540","url":null,"abstract":"Three-dimensional isothermal flow fields of rigid polyvinyl chloride are calculated under different wall slip conditions in the metering section of the twin-screw extruder by using the evolution technique in POLYFLOW. The relationship between the shear stress at the screw wall and the slip velocity of the flowing melt obeys Navier's linear law. Calculations show that the differences in velocity, pressure, shear rate, and viscosity between partial-slip condition and full-slip condition are so small. Then, only the results of full-slip and no-slip conditions were presented in the paper. The results show, when the slip coefficient is smaller than the critical value, the pressure difference between the entrance and exit of the melting section of the twin-screw extruder and the volumetric flow rate are constant, corresponding to the full slip condition. When the slip coefficient exceeds the critical value, with the slip coefficient increasing, the pressure difference and the gradients of velocity and pressure increase. The residual stress of the product is thus reduced. Therefore, increasing wall slip is good for the stability of polymer extrusion and the product quality. By using the particle tracking analysis method, the dispersive and the distributive mixing of the twin-screw extruder under full slip and no slip conditions are also studied. Results show that the dispersive mixing performance of the extruder is better under no-slip conditions than under full-slip conditions, but the distributive mixing performance is better under slip conditions than no-slip conditions. The slip at the wall is good for the extrusion of heat-sensitive materials.","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":"127676868","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}

{"title":"Torque controller design for electrical load simulator with estimation and compensation of parametric uncertainty","authors":"N. Ullah, Shaoping Wang","doi":"10.1109/IBCAST.2012.6177519","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177519","url":null,"abstract":"This paper proposes adaptive robust controller for electrical load simulator with estimation of parameters uncertainties and updating the model parameters to minimize model error Fuzzy logic is used to estimate the total disturbance which is function of extra torque and mechanical parameters variation. Estimation algorithm for parameters variation is derived from voltage and torque balance equations of electrical load simulator with suitable adaptive learning rate. A robust torque controller is derived from torque state equation of electrical load simulator and its stability is guaranteed using Lyapunov stability analysis. The validity of proposed controller is verified using computer simulations.","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":"133443637","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}

{"title":"Channel equalization for Discrete Wavelet Multitone transceiver in wireline channels","authors":"A. Khan, S. Baig","doi":"10.1109/IBCAST.2012.6177586","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177586","url":null,"abstract":"Discrete Wavelet Transform (DWT) based Multicarrier modulation (MCM) technique, namely Discrete Wavelet Multitone is a modified form of the Fourier Transform based Discrete Multitone (DMT) modulation technique, designated for wireline channels like DSL, Powerline, etc. DWMT has been recently proposed in order to overcome the drawbacks posed by DMT transceivers, such as inter-channel interference due to high side lobes, less spectral containment, use of cyclic prefixing, etc. The equalization issue with reference to DWMT is an active research area. We have analyzed the performance of a DWMT transceiver with time domain equalization techniques and compared it with DMT technique. Moreover this paper proposes the application of Overlap frequency domain equalization technique, and it is shown that Overlap-FDE gives same performance but with low complexity for the DSL channel.","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":"132104403","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}

{"title":"Investigation on existence and evolution of attachment saddle point structure of 3-D separation in juncture flow","authors":"Hua Zhang, H. Bo, M. Younis, H. Wang, Y. Liu","doi":"10.1109/IBCAST.2012.6177561","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177561","url":null,"abstract":"The PIV experimental investigation on attachment saddle point structure of 3-D laminar separation in juncture flow has been shown in this paper. The experimental results confirmed the existence of attachment saddle point structure in juncture flow formed by different shape of models mounted on flat plate under certain Reynolds number and boundary layer conditions. The new separation structure is different from the typical separation saddle point structure that in symmetrical plane the streamlines near the surface don't rise or separated from the surface but tend to attach to the surface, the vortex sheet does not depart from the surface but from a space singular point. Flow parameters as Reynolds number and model bluntness may influence the evolution of the separation structure from one to another. Under curtain boundary layer and model conditions, as Reynolds number is increasing the juncture flow may change from attachment saddle point structure to typical separation saddle point structure. Under curtain boundary layer and Reynolds number condition, as model bluntness is increasing the juncture flow may also change from attachment saddle point structure to typical separation saddle point structure. The attachment saddle point structure in 3-D separation flow could be taken as the generalization of Lighthill's 3-D separation mode.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"47 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":"115124884","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}

{"title":"Critical analysis of hopfield's neural network model for TSP and its comparison with heuristic algorithm for shortest path computation","authors":"Farah Sarwar, A. A. Bhatti","doi":"10.1109/IBCAST.2012.6177538","DOIUrl":"https://doi.org/10.1109/IBCAST.2012.6177538","url":null,"abstract":"For shortest path computation, Travelling-Salesman problem is NP-complete and is among the intensively studied optimization problems. Hopfield and Tank's proposed neural network based approach, for solving TSP, is discussed. Since original Hopfield's model suffers from some limitations as the number of cities increase, some modifications are discussed for better performance. With the increase in the number of cities, the best solutions provided by original Hopfield's neural network were considered to be far away from those provided by Lin and Kernighan using Heuristic algorithm. Results of both approaches are compared for different number of cities and are analyzed properly.","PeriodicalId":251584,"journal":{"name":"Proceedings of 2012 9th International Bhurban Conference on Applied Sciences & Technology (IBCAST)","volume":"54 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":"125693478","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}