LONG-TERM GOALS Goals for this project include: 1) the characterization of ocean acoustic impulse response (OAIR) in shallow water under various environmental conditions, 2) the development of predictive and synoptic methodologies/models linking acoustic communications system (modem) performance to environmental factors. Ultimately this information can be used to develop a robust acoustic modem...

Through analysis on principles of Binary Phase Shift Keying(2PSK) modulation and demodulation, the design scheme based on DSP Builder of DDS (Direct Digital frquency Synthesizer) is put forward. By using DSP Builder complete modulation and demodulation model, carrier signal was generated by DDS signal source. The circuit hardware structure of this design is simple and easy to implement. The mod...

that Gadamer associates with "health". Gaiger and Walker have translated Gadamer's critique of modem medicine in elegant and eminendly quotable language. Anyone interested in Gadamer, and anyone seeking quotable quotes from a famous and influential philosopher who is sceptical of the claims of modernism in medicine, would do well to peruse this book. Anyone interested in important new ideas abo...

Professor Cohn draws the important comparison between the witch-hunts and similar modem events, the common denominator being an attempt to eradicate from society a group of evil and corrupt individuals. It is clear from his book that many aspects of witchcraft will have to be reassessed, and in addition the several fertile ideas he puts forward demand further study. His postscript is devoted to...

High cost and high power consumption of underwater acoustic modem have limited the applications and researches of underwater wireless sensor networks (UWSN). This paper presents a node architecture and its low-cost realization to deal with such problems as high cost, high power consumption, large volume, and relative localization in a dense UWSN. Some fundamental functions like short range unde...

The well-known challenges in using the ionospheric skywave channel for data communications have been increasingly well-addressed by recent generations of HF data modems and link protocols. However, the means used to cope with the skywave channel present unusual challenges to Internet-style networkand application-layer protocols, which have been designed with reliable, high-bandwidth channels in...