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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 1-8 Text-to-speech conversion - Tamil language A text-to-speech conversion engine was developed for Tamil language that could successfully convert any arbitrary Tamil text into spoken utterance. The back-end of the engine was a sound database created with 343 phonemes which were chosen as the basic units of Tamil language. The text-to-speech engine splits the given text into the basic units of Tamil, extracts the correct phonemes from the database and concatenates the basic unit waveforms in the correct sequence to produce the required sound waveform. The front-end of the engine is a GUI interface that allows users to input Tamil text in letters or even numbers. The text can be stored to be used at a later time. The Tamil font ?TSC_Avarangal? was selected as the font to develop the user interface. The sound editing software ?Sound Forge? was used when preparing the phonemes with correct pitch. This work shows that for languages such as Tamil or Sinhala text-to-speech engines can be successfully developed with the available resources. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 9-20 Development of a universal PIC programmer Unlike other electronic components, a microcontroller has to be programmed to carry out a given task. Programming of most microcontrollers has to be done through external hardware connected to the microcontroller. For different families of microcontrollers the programming technique and the programming hardware are different. Even within the same family of microcontrollers programming technique can be different and the hardware setup can be different. In this project a universal programmer was designed and constructed for the family of Peripheral Interface Controller (PIC) microcontrollers. The programmer, which consists of software and hardware components, is capable of recognizing and programming all available members of the PIC family. The programmer can be modified to recognize and program any new member of the PIC family. The programmer can be controlled by an IBM compatible computer with Windows NT/2000/XP operating systems. In order to prohibit any unauthorized use of the programmer a security system is also introduced. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 21-27 CPLD based simple microprocessor for data acquisition This paper describes a simple microprocessor developed using a Complex Programmable Logic Device (CPLD), with an instruction set optimized for data acquisition applications. Most low-cost data acquisition systems are built using general purpose microcontrollers with large instruction sets. However, only a very small number of instructions are actually needed in data acquisition applications. Therefore, with the aim of minimizing the cost and lowering the overheads, a simple microprocessor was developed with a tiny instruction set containing only the instructions required in the data acquisition applications. Due to the optimization of the features, it was possible to fit both the CPU and the program memory in the 36 macrocell Xilinx XC9536XL CPLD costing approximately RS. 500. The design of the CPU was carried out using the hardware description language VHDL. Reconfigurability of the CPLD using VHDL makes it possible to change the features of the CPU, including the instruction set, to suit the user requirements. An example data acquisition system implemented using this CPU is also described in this paper. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 29-33 An extensible data acquisition and controlling system Data acquisition systems are indispensable in modern scientific research and in industrial automation. However, good general purpose data acquisition systems are rare and very costly. Another problem found in many such systems is lack of flexibility. The work reported in this paper is an attempt to develop a generic, extensible low cost data acquisition system. The flexibility of the hardware design has been achieved by relying on Complex Programmable Logic Devices (CPLD). In addition, a fully customizable and extensible software package has been developed. Software extensibility was achieved by providing a high-level API while flexibility was achieved by providing a fully configurable software application. The application allows controlling the output under predefined events, mathematical formulae or user plug-ins. It also provides data logging and analysing capabilities. In addition, a web interface is provided to maximize accessibility. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 49-56 The impact of 3D virtual environment models on asynchronous E-learning The growing need for lifelong learning, visualization and integration technologies in the field of e-learning environments has led to the application of virtual reality and the use of integrated virtual environments. This paper presents impact of 3D desktop virtual environments to learning and understanding, defined by user state of feelings. To evaluate the effectiveness of three dimensional viewers in e-learning, a special separate window has been integrated into the Authorware environment. The 2D and 3D Graphics designed have been enhanced to enable the integration and investigation of visualization in various computer Graphics concepts for students. Each Graphic element was designed using a different software development tool. More significantly, some of the tools have been enhanced to the degree where the user can interact and understand independently. This dramatically increases the quality of the tools i.e. patterns of interactions, 2D and 3D views of synthetic models. In general the result shows that these tools could promote the user interacting and enhance a sense of learning and the user understand the Computer Graphic concepts. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 57-61 Photovoltaic effects of dye-deposited metal electrodes in electrolytic media Photovoltaic effects of Methyl Violet dye deposited on copper electrodes have been extensively studied with I-/I3- redox couple. Methyl violet is an electron acceptor, which we used as the sensitizer of this study. Photocurrent of 150 mA/cm2 and photovoltage of 200 mV could be observed at 1000 W/m2 light intensity with this system. The photocurrent generation mechanism is thought to be transfer of electrons accepted by Methyl Violet dye from the copper plate on which the dye is deposited to the electrolyte with the photo excitation of the dye. The photocurrent action spectrum of the system consistent with the absorption spectrum of the dye indicating that photocurrent results from the excitation of the adsorb dye on copper plate. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 63-73 Fluctuation of sea surface temperature in the Indian Ocean during the period of 1971-1990 From the results, it was evident that bi-annual and annual oscillation peaks are strong in the study regions; however 6-month oscillation was dominant. In addition there was a spectral peak, which follows 60-month cycle. It is found that 60-month oscillation of SST is greater than that of 6-month fluctuation in several regions of the study domain. However, a strong 60-month fluctuation of SST was observed in the central Indian Ocean. There is an increase of SST by 0.33 0c was observed in the ocean surrounding Sri Lanka after the year 1978. However, decadal SST in seventies is different from the decadal SST in eighties in the study domain. A sudden increasing trend of SST was also seen in the region RX1 after the year 1977. It is observed that there is a decreasing trend in SST after occurrence of an El-Nino event. This decreasing of SST persists roughly 25 to 35 months. Further, there is an increasing trend of SST is observed from the end of the minimum SST and this increasing trend towards the next El-Nino event take place. This increasing trend takes 30 to 40 months to reach its maximum. There is a roughly 5-year fluctuation in SST in the region i.e. between any consequent two maximum SST or two minimum SST events. It is clearly noted that when El-Nino takes place, the SST values are high for the relevant year considered. Back to content page |
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Proceedings of the Technical Session of Institute of Physics, Sri Lanka 21 (2005) 75-85 Rainfall fluctuation in wet zone and dry zone of Sri Lanka during the time period of 1900 to 1996 The Wet Zone and Dry Zone rainfall stations exhibit different types of fluctuations within the period from 1900 ? 1996. In the Wet Zone rainfall stations, six-month oscillation is prominent. In the Dry Zone 12-month oscillation is prominent. It was found the rainfall fluctuation in 90 month, 150 month and 390-month oscillations are significant in Colombo. The Wet Zone and Dry Zone rainfall stations indicate 17-19 month oscillation has a high power density, which arises in every station. The periodic cycles of 36-48 months is clearly observed in the Wet Zone and Dry Zone rainfall stations of Sri Lanka. Spectral analysis clearly indicates an existence of five-year cycle and ten year of rainfall fluctuation in the Dry Zone and Wet zone for the period from 1900 to 1996. It is found that, in the Dry Zone there was a decreasing trend in rainfall during the period of 1918 to 1952 (34 years) and sharp decreasing trend occurred during 1963?1978. In the Wet Zone decreasing trend in rainfall from 1928 to 1961(33 years) was slightly high when compared with the decreasing trend in Dry Zone rainfall. It is found that there is a decreasing trend in rainfall in the Wet Zone from 1961 up to 1985. Back to content page |