Android Smartphone as a Microphone in SmartRoom System Pavel Y. - PowerPoint PPT Presentation

Android Smartphone as a Microphone in SmartRoom System Pavel Y. Kovyrshin, Dmitry G. Korzun Petrozavodsk State University Department of Computer Science Grant KA179 “Complex development of regional cooperation in the field of open ICT innovations” of Karelia ENPI CBC programme 2007–2013 of the European Union, the Russian Federation and the Republic of Finland 15 th FRUCT Conference April 24, 2014, St.-Petersburg, Russia Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 1 / 11

SmartRoom System Services Centralized data storage (SIB: Semantic Information Broker) Many mobile clients Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 2 / 11

Microphone-service: High Level Architecture JNI - enables Java to use native implementations SmartSlog - provides API for Smart Space interaction JSpeex - audio processing Java module DatagramSocket - Java implementation of UDP protocol User Datagram Protocol (UDP) is more suitable for such streaming applications like Microphone-service. Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 3 / 11

Microphone-service: Knowledge Processor Service is implemented as a single KP SmartSlog: SDK for KP development Ontology: service representation model (OWL, RDF) Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 4 / 11

Microphone-service: Workflow Scheme 1 Initialization 2 Publishing address 3 Listening for connections 4 Receiving and processing data 5 Playing audio flow Development: Microphone-service KP (server) and Client KP Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 5 / 11

Android Client: Architecture User interface Java-based module uses Android SDK JNI enables Java to use native implementations Application logic is C written and supported by Android NDK SmartSlog supports ontology-driven implementation: ◮ publication and extraction data ◮ subscription mechanism ◮ connection state tracking Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 6 / 11

Android Client for SmartRoom: User Interface Mobile device becomes a microphone Users: current speaker and chairman Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 7 / 11

Performance Experiments Wireless network quality strongly influences on service performance. Network transmission Audio processing Average Standard deviation τ = 50 ms σ = 6 ms ≈ 15 ms ¯ Figure: Transmission time of 500 UDP packets of 62 bytes Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 8 / 11

Performance: Our Solutions Audio processing: JSpeex codec ◮ based on CELP algorithm ◮ well-suited to handle VoIP ◮ suitable for unreliable transfer packets network UDP for real-time audio transfer Router configuration: selection of less used network channel Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 9 / 11

Metrics of Implementation Client side Server side Java code, loc. 138 293 C code, loc. 91 84 Devices Samsung Galaxy S3 Notebook Asus x200ca D-Link DIR-320 router Tools SmartSlog SDK, JSpeex Android SDK/NDK, JNI Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 10 / 11

Conclusion Released server (Linux) and client (Android) KPs Performance: solutions and experimental evaluation SourceForge: http://sourceforge.net/projects/smartroom/ files/services/microphone-service/ Project Wiki: http://oss.fruct.org/wiki/SmartRoom Android client: http://play.google.com/store/apps/details ?id=petrsu.smartroom.android.srclient My e-mail: kovyrshi@cs.karelia.ru Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 11 / 11