Pub Date : 2003-10-15DOI: 10.1109/TENCON.2003.1273368
M. Mitra, N.B. Singh
An efficient general-purpose optimizer based on "genetic algorithms" has been developed. The efficacy of the optimizer has been well demonstrated by implementing it for parameter extraction of pn junction diodes. With this technique, device parameters like built-in potential and grading coefficient for any diode can be extracted. If the grading coefficient shows the junction to be linear graded, effective diode area and doping gradient have been extracted. If the junction turns out to be an abrupt one, effective area and doping concentrations of each side have been obtained. It is also possible to obtain process parameters for other kinds of junctions with the inclusion of suitable models. This parameter extraction technique has been applied successfully to measured data for real diodes as well as simulated data with different noise levels.
{"title":"Study of pn junctions using genetic algorithm optimizer","authors":"M. Mitra, N.B. Singh","doi":"10.1109/TENCON.2003.1273368","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273368","url":null,"abstract":"An efficient general-purpose optimizer based on \"genetic algorithms\" has been developed. The efficacy of the optimizer has been well demonstrated by implementing it for parameter extraction of pn junction diodes. With this technique, device parameters like built-in potential and grading coefficient for any diode can be extracted. If the grading coefficient shows the junction to be linear graded, effective diode area and doping gradient have been extracted. If the junction turns out to be an abrupt one, effective area and doping concentrations of each side have been obtained. It is also possible to obtain process parameters for other kinds of junctions with the inclusion of suitable models. This parameter extraction technique has been applied successfully to measured data for real diodes as well as simulated data with different noise levels.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"685 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133132674","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273246
M. Meshram, N. K. Agrawal, B. Sinha, P. S. Misra
We present the development and design analysis of a multi layer microwave absorber. Three samples of M type hexagonal ferrite powders, namely [Ba(MnTi)/sub /spl delta//Fe/sub (12-2/spl delta/)/O/sub 19/] for /spl delta/ = 1.6, 1.7 and 1.8, have been developed using the dry attrition and sintering process. On the basis of the transmission line model, the microwave absorption for a three layer microwave absorber with different combinations of ferrite for an overall coating thickness of 1.5 mm have been computed. It has been found that the three layer microwave absorber with each layer of different composition provides broad band characteristics with a minimum of 10 dB absorption from 12.5 to 18 GHz. This type of microwave absorber is very useful in military application for reducing the radar cross section of the target.
{"title":"Transmission line modeling (TLM) for evaluation of absorption in ferrite based multi layer microwave absorber","authors":"M. Meshram, N. K. Agrawal, B. Sinha, P. S. Misra","doi":"10.1109/TENCON.2003.1273246","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273246","url":null,"abstract":"We present the development and design analysis of a multi layer microwave absorber. Three samples of M type hexagonal ferrite powders, namely [Ba(MnTi)/sub /spl delta//Fe/sub (12-2/spl delta/)/O/sub 19/] for /spl delta/ = 1.6, 1.7 and 1.8, have been developed using the dry attrition and sintering process. On the basis of the transmission line model, the microwave absorption for a three layer microwave absorber with different combinations of ferrite for an overall coating thickness of 1.5 mm have been computed. It has been found that the three layer microwave absorber with each layer of different composition provides broad band characteristics with a minimum of 10 dB absorption from 12.5 to 18 GHz. This type of microwave absorber is very useful in military application for reducing the radar cross section of the target.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130357150","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273203
A. Chalechale, A. Mertins
A novel fast method for line segment extraction based on chain code representation of thinned sketches (or edge maps) is presented and exploited for Persian signature recognition. The method has a parallel nature and can be employed on parallel machines. It breaks the macro chains into several micro chains after applying shifting, smoothing and differentiating. The micro chains are then approximated by straight line segments. Length and position distributions of the extracted line segments are used to make a compact feature vector for Iranian cursive signature. The feature vector is invariant under affine transforms and can be used effectively in paperless office projects. Experimental results show fast response and accurate recognition/retrieval rate.
{"title":"Line segment distribution of sketches for Persian signature recognition","authors":"A. Chalechale, A. Mertins","doi":"10.1109/TENCON.2003.1273203","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273203","url":null,"abstract":"A novel fast method for line segment extraction based on chain code representation of thinned sketches (or edge maps) is presented and exploited for Persian signature recognition. The method has a parallel nature and can be employed on parallel machines. It breaks the macro chains into several micro chains after applying shifting, smoothing and differentiating. The micro chains are then approximated by straight line segments. Length and position distributions of the extracted line segments are used to make a compact feature vector for Iranian cursive signature. The feature vector is invariant under affine transforms and can be used effectively in paperless office projects. Experimental results show fast response and accurate recognition/retrieval rate.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125549603","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273376
S. Annadurai, R. Shanmugalakshmi
In this paper a new image compression technique for color images using bit reduction and Burrows Wheeler transform is proposed. This method adopts the advantages in BWT based text compression to compressing images also. A bit encoding schemes that select blocks of pixel values from the source image and convert those pixel values in to equivalent alphabets (A-Z, a-z), thereby we acquire a new encoded text file consisting of only the alphabets. The BWT based compression method can be now applied to the above said text file to compress it. To increase the compression rate some variant methods in the encoding phase are also proposed in this paper. The experimental results have shown a significant improvement in the compression ratios compared to other techniques.
{"title":"Color image compression using bit reduction and Burrows Wheeler transform","authors":"S. Annadurai, R. Shanmugalakshmi","doi":"10.1109/TENCON.2003.1273376","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273376","url":null,"abstract":"In this paper a new image compression technique for color images using bit reduction and Burrows Wheeler transform is proposed. This method adopts the advantages in BWT based text compression to compressing images also. A bit encoding schemes that select blocks of pixel values from the source image and convert those pixel values in to equivalent alphabets (A-Z, a-z), thereby we acquire a new encoded text file consisting of only the alphabets. The BWT based compression method can be now applied to the above said text file to compress it. To increase the compression rate some variant methods in the encoding phase are also proposed in this paper. The experimental results have shown a significant improvement in the compression ratios compared to other techniques.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122098721","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273351
R. Muralishankar, R. Srikanth, A. Ramakrishnan
In this paper, we present two new methods for vowel-consonant segmentation of a co-articulated basic-units employed in our Thirukkural Tamil text-to-speech synthesis system (G. L. Jayavardhana Rama et al, IEEE workshop on Speech Synthesis, 2002). The basic-units considered in this are CV, VC, VCV, VCCV and VCCC, where C stands for a consonant and V for any vowel. In the first method, we use a subspace-based approach for vowel-consonant segmentation. It uses oriented principal component analysis (OPCA) where the test feature vectors are projected on to the V and C subspaces. The crossover of the norm-contours obtained by projecting the test basic-unit onto the V and C subspaces give the segmentation points which in turn helps in identifying the V and C durations of a test basic-unit. In the second method, we use probabilistic principal component analysis (PPCA) to get probability models for V and C. We then use the Neymen-Pearson (NP) test to segment the basic-unit into V and C. Finally, we show that the hypothesis testing turns out to be an energy detector for V-C segmentation which is similar to the first method.
{"title":"Subspace and hypothesis based effective segmentation of co-articulated basic-units for concatenative speech synthesis","authors":"R. Muralishankar, R. Srikanth, A. Ramakrishnan","doi":"10.1109/TENCON.2003.1273351","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273351","url":null,"abstract":"In this paper, we present two new methods for vowel-consonant segmentation of a co-articulated basic-units employed in our Thirukkural Tamil text-to-speech synthesis system (G. L. Jayavardhana Rama et al, IEEE workshop on Speech Synthesis, 2002). The basic-units considered in this are CV, VC, VCV, VCCV and VCCC, where C stands for a consonant and V for any vowel. In the first method, we use a subspace-based approach for vowel-consonant segmentation. It uses oriented principal component analysis (OPCA) where the test feature vectors are projected on to the V and C subspaces. The crossover of the norm-contours obtained by projecting the test basic-unit onto the V and C subspaces give the segmentation points which in turn helps in identifying the V and C durations of a test basic-unit. In the second method, we use probabilistic principal component analysis (PPCA) to get probability models for V and C. We then use the Neymen-Pearson (NP) test to segment the basic-unit into V and C. Finally, we show that the hypothesis testing turns out to be an energy detector for V-C segmentation which is similar to the first method.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125650990","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273172
J. Muruganantham, R. Amarnath, K.V. Jawahar, C. Kalyanasundaram
The emergence of cardiac surgery and with it an imperative need for precise anatomical diagnosis have revived the technical advancement necessary for the amplification and recording of cardiovascular sounds. The study of phonocardiography has developed out of this confidence. The recordings of the sounds, produced by the mechanical activity of the human heart that contains vital information are called phonocardiogram and the device used to record is called phonocardiograph. The objective of this work is to find an efficient method to diagnose the heart diseases from their heart sounds. We have implemented various methods including neural network, fuzzy system and wavelets to recognize the heart diseases and their efficiencies were compared with each other.
{"title":"Methods for classification of phonocardiogram","authors":"J. Muruganantham, R. Amarnath, K.V. Jawahar, C. Kalyanasundaram","doi":"10.1109/TENCON.2003.1273172","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273172","url":null,"abstract":"The emergence of cardiac surgery and with it an imperative need for precise anatomical diagnosis have revived the technical advancement necessary for the amplification and recording of cardiovascular sounds. The study of phonocardiography has developed out of this confidence. The recordings of the sounds, produced by the mechanical activity of the human heart that contains vital information are called phonocardiogram and the device used to record is called phonocardiograph. The objective of this work is to find an efficient method to diagnose the heart diseases from their heart sounds. We have implemented various methods including neural network, fuzzy system and wavelets to recognize the heart diseases and their efficiencies were compared with each other.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124918871","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273285
A.G. Bhutad, S. V. Kulkarni, S. Khaparde
A distribution system has certain distinguishing features which make it different and somewhat difficult to analyze as compared to a transmission system. Unbalanced loads, untransposed lines, single-phase and two-phase laterals are some of them. The distribution system needs to be analyzed on the three-phase basis instead of the single-phase basis. Hence, the three-phase load flow for the distribution system is significantly different from the conventional load flow for the transmission system. In this paper, various load flow methods for distribution systems are reviewed. These methods are applied on a sample 8-bus system. The results are reported. The performance of these methods is compared for various parameters.
{"title":"Three-phase load flow methods for radial distribution networks","authors":"A.G. Bhutad, S. V. Kulkarni, S. Khaparde","doi":"10.1109/TENCON.2003.1273285","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273285","url":null,"abstract":"A distribution system has certain distinguishing features which make it different and somewhat difficult to analyze as compared to a transmission system. Unbalanced loads, untransposed lines, single-phase and two-phase laterals are some of them. The distribution system needs to be analyzed on the three-phase basis instead of the single-phase basis. Hence, the three-phase load flow for the distribution system is significantly different from the conventional load flow for the transmission system. In this paper, various load flow methods for distribution systems are reviewed. These methods are applied on a sample 8-bus system. The results are reported. The performance of these methods is compared for various parameters.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"21 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131540143","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273410
V. Khanna, H. Gupta, S. Maheshwari
Stations in IEEE 802.11 ad-hoc WLAN protocol exchange frames by contending for the channel using CSMA/CA mechanisms and follow the binary exponential backoff for retransmitting the frames on collisions. This contention and collisions lead to low throughput. The protocol facilitates power saving in stations by allowing the stations to enter sleep mode. However, once these stations wakeup they can receive the frames only after contending for the channel. This leads to long awake periods and high power consumption. We have devised improved mechanisms that facilitate transmissions with reduced contention. Our mechanisms allow the data frames to be transmitted contention-free, leading to high throughput. The stations also have to keep awake for short duration to receive these frames in a contention-free manner, leading to high power saving. The mechanisms involve only minimal software changes to the existing protocol and can be implemented on the existing 802.11 WLAN cards. The stations following these mechanisms can co-exist in a standard 802.11 based ad-hoc WLAN. The average power consumption in our mechanisms is only 1/6/sup th/ of the power consumed in 802.11b protocol, with the stations consuming 84% lesser power. Our maximum throughput improved to 25% higher than throughput of 802.11b protocol.
{"title":"Contention free data transfers in IEEE 802.11 ad-hoc wireless LAN protocol: an analysis","authors":"V. Khanna, H. Gupta, S. Maheshwari","doi":"10.1109/TENCON.2003.1273410","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273410","url":null,"abstract":"Stations in IEEE 802.11 ad-hoc WLAN protocol exchange frames by contending for the channel using CSMA/CA mechanisms and follow the binary exponential backoff for retransmitting the frames on collisions. This contention and collisions lead to low throughput. The protocol facilitates power saving in stations by allowing the stations to enter sleep mode. However, once these stations wakeup they can receive the frames only after contending for the channel. This leads to long awake periods and high power consumption. We have devised improved mechanisms that facilitate transmissions with reduced contention. Our mechanisms allow the data frames to be transmitted contention-free, leading to high throughput. The stations also have to keep awake for short duration to receive these frames in a contention-free manner, leading to high power saving. The mechanisms involve only minimal software changes to the existing protocol and can be implemented on the existing 802.11 WLAN cards. The stations following these mechanisms can co-exist in a standard 802.11 based ad-hoc WLAN. The average power consumption in our mechanisms is only 1/6/sup th/ of the power consumed in 802.11b protocol, with the stations consuming 84% lesser power. Our maximum throughput improved to 25% higher than throughput of 802.11b protocol.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134312572","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273272
B. Shanmukha Rao, S. V. Rao, G. Sajith
We discuss the design and implementation of a meta search engine, which deduces the user's information needs with the help of profiles made from query and proxy log records, and produces focused search results.
{"title":"A user-profile assisted meta search engine","authors":"B. Shanmukha Rao, S. V. Rao, G. Sajith","doi":"10.1109/TENCON.2003.1273272","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273272","url":null,"abstract":"We discuss the design and implementation of a meta search engine, which deduces the user's information needs with the help of profiles made from query and proxy log records, and produces focused search results.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132077393","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273371
M.J. Kumar, C. Reddy
We introduce a novel approach, called dual bandgap SiC-on-Si emitter, to reduce the collector emitter offset voltage in the case of wide bandgap SiC-emitter PNP HBTs. In our approach, the collector-emitter offset-voltage is reduced significantly by partially eliminating the built-in potential difference between the emitter-base junction and collector-base junction. We have evaluated the performance of the proposed device in detail using 2D device simulation. The proposed dual bandgap SiC-on-Si P-emitter SiGe N-base lateral Schottky metal-collector (PNM) HBT is shown to exhibit a current gain close to that of the wide bandgap emitter (SiC) PNP HBT while its collector-emitter offset-voltage is significantly lower than that of the SiC PNP HBT. The transient response of the proposed structure is also much superior due to its Schottky collector.
{"title":"A new dual-bandgap SiC-on-Si p-emitter, SiGe n-base, lateral Schottky metal-collector (PNM) HBT on SOI with reduced collector-emitter offset voltage","authors":"M.J. Kumar, C. Reddy","doi":"10.1109/TENCON.2003.1273371","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273371","url":null,"abstract":"We introduce a novel approach, called dual bandgap SiC-on-Si emitter, to reduce the collector emitter offset voltage in the case of wide bandgap SiC-emitter PNP HBTs. In our approach, the collector-emitter offset-voltage is reduced significantly by partially eliminating the built-in potential difference between the emitter-base junction and collector-base junction. We have evaluated the performance of the proposed device in detail using 2D device simulation. The proposed dual bandgap SiC-on-Si P-emitter SiGe N-base lateral Schottky metal-collector (PNM) HBT is shown to exhibit a current gain close to that of the wide bandgap emitter (SiC) PNP HBT while its collector-emitter offset-voltage is significantly lower than that of the SiC PNP HBT. The transient response of the proposed structure is also much superior due to its Schottky collector.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133367266","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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