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

android smartphone as a microphone in smartroom system
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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


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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

  • f open ICT innovations” of Karelia ENPI CBC programme 2007–2013 of the European Union,

the Russian Federation and the Republic of Finland

15th FRUCT Conference April 24, 2014, St.-Petersburg, Russia

Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 1 / 11

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SmartRoom System Services

Centralized data storage (SIB: Semantic Information Broker) Many mobile clients

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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

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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

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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

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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

  • ntology-driven implementation:

◮ publication and extraction data ◮ subscription mechanism ◮ connection state tracking Pavel Kovyrshin Microphone Service for SmartRoom FRUCT15 6 / 11

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Android Client for SmartRoom: User Interface

Mobile device becomes a microphone Users: current speaker and chairman

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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

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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

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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

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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

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