2017 IEEE International Conference on Signal Processing, Informatics, Communication and Energy Systems (SPICES), 2017
The study of electric field is an important tool for lightning research. Electric Field Mills (EF... more The study of electric field is an important tool for lightning research. Electric Field Mills (EFMs) are electromechanical devices used to observe static atmospheric electric fields during fair weather and during storm conditions. EFM readings show significant changes in electric field due to an approaching thunderstorm and particularly, during lightning periods. Attempts to comprehend the variations prior to and after a strike has been done by observatories all over the world. This paper focuses on identifying characteristic changes in atmospheric electric field prior to a lightning strike. Both static and dynamic field changes are studied by means of literature survey and static field variations are also studied through analysis of EFM data from Sonnblick Observatory, Austria and National Centre for Earth Science Studies (NCESS), Trivandrum, Kerala. During thunderstorms and the few seconds prior to lightning, significant changes are observed in both static and dynamic electric fie...
Abstract This paper reports a comparative investigation on acoustic comfort of classrooms in vern... more Abstract This paper reports a comparative investigation on acoustic comfort of classrooms in vernacular and modern school buildings in tropical warm humid climate. In this type of climate the intrusion of external noise into the classrooms along with cross ventilation is unavoidable. Preliminary investigation on the evaluation of acoustic comfort carried in secondary schools located in Kollam district of Kerala State in India have been reported. As a step ahead, in order to understand the performance of vernacular school classroom in comparison with that of a modern classroom, an initial survey was conducted in classrooms of ten vernacular and 10 modern schools. Further a detail investigation was carried out in a vernacular and modern school building located in the same site. The study was conducted by measuring the two important acoustic parameters viz., background noise and reverberation time which affect the acoustical comfort in the classrooms. The level of satisfaction of the users was evaluated through questionnaires distributed to teachers and students. The result of the scientific analysis was compared to user’s response. The study reveals that modern classrooms are more preferred than vernacular classrooms acoustically, by the teachers and students. The study also confirms a strong need of improving the acoustical comforts in the classrooms.
Abstract Electronic journals and electronic books play a crucial role in the changing scenario of... more Abstract Electronic journals and electronic books play a crucial role in the changing scenario of libraries and information centres. This paper deals with the emerging technology of electronic publishing. The paper covers e-journals, e-books, advantages of e-journals and ...
The possibility of using chaos for the encryption and decryption of message signals in communicat... more The possibility of using chaos for the encryption and decryption of message signals in communication systems has been widely used and accepted. Hyperchaotic dynamics of high dimensionality is featured in chaos generated by systems with delayed nonlinear feedback. An efficient and fast encryption and decryption scheme exploiting hyperchaotic regimes of a nonlinear oscillator with time delay feedback is proposed. Information is transmitted by adding a small amplitude message signal to a large chaotic carrier, the latter effectively hiding the former. The message is extracted at the receiver by subtracting the chaos created in the receiver from the transmitted chaos-plus-message signal. The cryptographic systems demonstrated here is based on chaotic devices with delayed nonlinear feedback, which features a high robustness of the chaos synchronization and a very good performance in terms of stability and information recovery.
The famous chaotic circuit known as Chua's oscillator, despite the robustness of the chaotic ... more The famous chaotic circuit known as Chua's oscillator, despite the robustness of the chaotic behavior to parametric mismatches, requires the construction of noncommercial valued inductor. A low cost inductorless version of Chua's oscillator is presented. The chaotic behavior of the circuit is verified by PSpice simulation and also by experimental study on a circuit breadboard. The results lead to excellent agreement with each other and with the results of previous investigators. Experimental results on the possibility of controlling chaos in the modified Chua's oscillator by the inherent feedback mechanism are also reported.
This paper reports the investigation on acoustic comfort of school buildings in tropical warm hum... more This paper reports the investigation on acoustic comfort of school buildings in tropical warm humid climate. In this type of climate the intrusion of external noise into the classrooms along with cross ventilation is unavoidable. Studies have been carried in 30 secondary schools located in Kollam district of Kerala in India. The two important acoustic parameters viz., background noise and reverberation time which affect the acoustical comfort were measured on site, in the school environment and a few selected classrooms in all schools. The measured values were compared to the acoustical recommendations of Bureau of Indian standards. The acoustical study on one of the schools is presented in detail. The study reveals a strong need of improving the acoustical comforts in school environments and classrooms. The study also reveals that a simple treatment to the ceiling and walls could improve the acoustic comfort in classrooms.
— The study of electric field is an important tool for lightning research. Electric Field Mills (... more — The study of electric field is an important tool for lightning research. Electric Field Mills (EFMs) are electro-mechanical devices used to observe static atmospheric electric fields during fair weather and during storm conditions. EFM readings show significant changes in electric field due to an approaching thunderstorm and particularly, during lightning periods. Attempts to comprehend the variations prior to and after a strike has been done by observatories all over the world. This paper focuses on identifying characteristic changes in atmospheric electric field prior to a lightning strike. Both static and dynamic field changes are studied by means of literature survey and static field variations are also studied through analysis of EFM data from Sonnblick Observatory, Austria and National Centre for Earth Science Studies (NCESS), Trivandrum, Kerala. During thunderstorms and the few seconds prior to lightning, significant changes are observed in both static and dynamic electric fields. Static field changes include a magnitude rise and reversal of direction of electric field from the fair weather situation, and dynamic field changes are characterized by the occurrence of Preliminary Breakdown Pulses(PBP) which is the dynamic electrical activity inside the cloud before a strike.This study, by identifying the characteristic changes in atmospheric electric field prior to lightning strike by comparing multiple observations from different parts of the world ,points to great possibilities in the field of lightning prediction.
2017 IEEE International Conference on Signal Processing, Informatics, Communication and Energy Systems (SPICES), 2017
The study of electric field is an important tool for lightning research. Electric Field Mills (EF... more The study of electric field is an important tool for lightning research. Electric Field Mills (EFMs) are electromechanical devices used to observe static atmospheric electric fields during fair weather and during storm conditions. EFM readings show significant changes in electric field due to an approaching thunderstorm and particularly, during lightning periods. Attempts to comprehend the variations prior to and after a strike has been done by observatories all over the world. This paper focuses on identifying characteristic changes in atmospheric electric field prior to a lightning strike. Both static and dynamic field changes are studied by means of literature survey and static field variations are also studied through analysis of EFM data from Sonnblick Observatory, Austria and National Centre for Earth Science Studies (NCESS), Trivandrum, Kerala. During thunderstorms and the few seconds prior to lightning, significant changes are observed in both static and dynamic electric fie...
Abstract This paper reports a comparative investigation on acoustic comfort of classrooms in vern... more Abstract This paper reports a comparative investigation on acoustic comfort of classrooms in vernacular and modern school buildings in tropical warm humid climate. In this type of climate the intrusion of external noise into the classrooms along with cross ventilation is unavoidable. Preliminary investigation on the evaluation of acoustic comfort carried in secondary schools located in Kollam district of Kerala State in India have been reported. As a step ahead, in order to understand the performance of vernacular school classroom in comparison with that of a modern classroom, an initial survey was conducted in classrooms of ten vernacular and 10 modern schools. Further a detail investigation was carried out in a vernacular and modern school building located in the same site. The study was conducted by measuring the two important acoustic parameters viz., background noise and reverberation time which affect the acoustical comfort in the classrooms. The level of satisfaction of the users was evaluated through questionnaires distributed to teachers and students. The result of the scientific analysis was compared to user’s response. The study reveals that modern classrooms are more preferred than vernacular classrooms acoustically, by the teachers and students. The study also confirms a strong need of improving the acoustical comforts in the classrooms.
Abstract Electronic journals and electronic books play a crucial role in the changing scenario of... more Abstract Electronic journals and electronic books play a crucial role in the changing scenario of libraries and information centres. This paper deals with the emerging technology of electronic publishing. The paper covers e-journals, e-books, advantages of e-journals and ...
The possibility of using chaos for the encryption and decryption of message signals in communicat... more The possibility of using chaos for the encryption and decryption of message signals in communication systems has been widely used and accepted. Hyperchaotic dynamics of high dimensionality is featured in chaos generated by systems with delayed nonlinear feedback. An efficient and fast encryption and decryption scheme exploiting hyperchaotic regimes of a nonlinear oscillator with time delay feedback is proposed. Information is transmitted by adding a small amplitude message signal to a large chaotic carrier, the latter effectively hiding the former. The message is extracted at the receiver by subtracting the chaos created in the receiver from the transmitted chaos-plus-message signal. The cryptographic systems demonstrated here is based on chaotic devices with delayed nonlinear feedback, which features a high robustness of the chaos synchronization and a very good performance in terms of stability and information recovery.
The famous chaotic circuit known as Chua's oscillator, despite the robustness of the chaotic ... more The famous chaotic circuit known as Chua's oscillator, despite the robustness of the chaotic behavior to parametric mismatches, requires the construction of noncommercial valued inductor. A low cost inductorless version of Chua's oscillator is presented. The chaotic behavior of the circuit is verified by PSpice simulation and also by experimental study on a circuit breadboard. The results lead to excellent agreement with each other and with the results of previous investigators. Experimental results on the possibility of controlling chaos in the modified Chua's oscillator by the inherent feedback mechanism are also reported.
This paper reports the investigation on acoustic comfort of school buildings in tropical warm hum... more This paper reports the investigation on acoustic comfort of school buildings in tropical warm humid climate. In this type of climate the intrusion of external noise into the classrooms along with cross ventilation is unavoidable. Studies have been carried in 30 secondary schools located in Kollam district of Kerala in India. The two important acoustic parameters viz., background noise and reverberation time which affect the acoustical comfort were measured on site, in the school environment and a few selected classrooms in all schools. The measured values were compared to the acoustical recommendations of Bureau of Indian standards. The acoustical study on one of the schools is presented in detail. The study reveals a strong need of improving the acoustical comforts in school environments and classrooms. The study also reveals that a simple treatment to the ceiling and walls could improve the acoustic comfort in classrooms.
— The study of electric field is an important tool for lightning research. Electric Field Mills (... more — The study of electric field is an important tool for lightning research. Electric Field Mills (EFMs) are electro-mechanical devices used to observe static atmospheric electric fields during fair weather and during storm conditions. EFM readings show significant changes in electric field due to an approaching thunderstorm and particularly, during lightning periods. Attempts to comprehend the variations prior to and after a strike has been done by observatories all over the world. This paper focuses on identifying characteristic changes in atmospheric electric field prior to a lightning strike. Both static and dynamic field changes are studied by means of literature survey and static field variations are also studied through analysis of EFM data from Sonnblick Observatory, Austria and National Centre for Earth Science Studies (NCESS), Trivandrum, Kerala. During thunderstorms and the few seconds prior to lightning, significant changes are observed in both static and dynamic electric fields. Static field changes include a magnitude rise and reversal of direction of electric field from the fair weather situation, and dynamic field changes are characterized by the occurrence of Preliminary Breakdown Pulses(PBP) which is the dynamic electrical activity inside the cloud before a strike.This study, by identifying the characteristic changes in atmospheric electric field prior to lightning strike by comparing multiple observations from different parts of the world ,points to great possibilities in the field of lightning prediction.
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