Cyber-Physical Systems Laboratory - User contributions [en]

CSE730x Research Seminar

2019-02-26T16:09:00Z

Dolvara:

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* '''Instructor:''' [http://www.cse.wustl.edu/~lu Prof. Chenyang Lu]
* '''Time: Friday at 4pm-5pm, Location: Jolley 224'''
* '''Google group:''' [http://groups.google.com/group/wu-systems-seminar google group]

This seminar examines fundamental and emerging concepts in concurrency and distribution by studying seminal papers and recent research results. Broad topics of interest include models of concurrency, mobile computing, parallel architectures, sensor networks, distributed algorithms, and specialized protocols. Each semester, the seminar emphasizes different themes reflecting the current research interests of the participants.

The theme of this semester's seminar is Wireless Sensor Networks. We will read and discuss papers from recent major conferences on mobile, wireless, and sensor networks and systems. These conferences include:

* SenSys ([http://sensys.acm.org])
* IPSN ([http://ipsn.acm.org])
* RTSS ([http://www.rtss.org/])
* RTAS ([http://www.rtas.org/])
* ICCPS ([http://www.iccps.org])
* Wireless Health ([http://www.wirelesshealth2013.org/])
* MobiCom ([http://www.sigmobile.org/mobicom/2013/])
* MobiSys ([http://www.sigmobile.org/mobisys/2013/])
* Sigcomm ([http://conferences.sigcomm.org/sigcomm/2013/])
* NSDI ([https://www.usenix.org/conference/nsdi14])
* SOSP ([http://http://sigops.org/sosp/sosp13/])
* OSDI ([https://www.usenix.org/conference/osdi14/])

=== ---January 4 ---===

Ruixuan

=== ---January 11 ---===

Cancelled

=== ---January 18 ---===

Ben (Practice Talk)

=== ---January 25 ---===

Dee

=== ---February 1 ---===

Yehan

=== ---February 8 ---===

Dingwen

=== ---February 15 ---===

Haoran

=== ---February 22 ---===

Chao

=== ---March 1 ---===

Jiangnan

=== ---March 8 ---===

Chong

=== ---March 15 ---===

Ruixuan

=== ---March 22 ---===

Yehan

=== ---March 29 ---===

Dingwen

=== ---April 5 ---===

Haoran

=== ---April 12 ---===

Chao

=== ---April 19 ---===

Jiangnan

=== ---April 26 ---===

Chong

==Previous Semesters==
* [[Seminar Fall 2018|Fall 2018]]
* [[Seminar Summer 2018|Summer 2018]]
* [[Seminar Spring 2018|Spring 2018]]
* [[Seminar Fall 2017|Fall 2017]]
* [[Seminar Summer 2017|Summer 2017]]
* [[Seminar Spring 2017|Spring 2017]]
* [[Seminar Fall 2016|Fall 2016]]
* [[Seminar Summer 2016|Summer 2016]]
* [[Seminar Spring 2016|Spring 2016]]
* [[Seminar Fall 2015|Fall 2015]]
* [[Seminar Summer 2015|Summer 2015]]
* [[Seminar Spring 2015|Spring 2015]]
* [[Seminar Fall 2014|Fall 2014]]
* [[Seminar Summer 2014|Summer 2014]]
* [[Seminar Spring 2014|Spring 2014]]
* [[Seminar Fall 2013|Fall 2013]]
* [[Seminar Summer 2013|Summer 2013]]
* [[Seminar Spring 2013|Spring 2013]]
* [[Seminar Fall 2012|Fall 2012]]
* [[Seminar Summer 2012|Summer 2012]]
* [[Seminar Spring 2012|Spring 2012]]
* [[Seminar Fall 2011|Fall 2011]]
* [[Seminar Summer 2011|Summer 2011]]
* [[Seminar Spring 2011|Spring 2011]]
* [[Seminar Fall 2010|Fall 2010]]
* [[Seminar Spring 2010|Spring 2010]]
* [[Seminar Fall 2009|Fall 2009]]
* [[Seminar Summer 2009|Summer 2009]]
* [[Seminar Spring 2009|Spring 2009]]
* [[Seminar Fall 2008|Fall 2008]]
* [[Seminar Summer 2008|Summer 2008]]
* [[Seminar Spring 2008|Spring 2008]]
* [[Fall 2007]]
* [[Summer 2007]]
* [[Spring 2007]]
* [[Fall 2006]]
* [[Spring 2006]]
* [[Fall 2005]]
* [[Spring 2005]]
* [[Fall 2004]]
* [[Spring 2004]]
* [[Fall 2003]]
* [[Spring 2003]]
* [[Fall 2002]]
* [http://userfs.cec.wustl.edu/~cs673/spring.2002.html Spring 2002]
* [http://userfs.cec.wustl.edu/~cs673/fall.2001.html Fall 2001]
* [http://userfs.cec.wustl.edu/~cs673/spring.2001.html Spring 2001]
* [[Fall 2000]]
* [http://userfs.cec.wustl.edu/~cs673/spring.2000.html Spring 2000]
* [http://cec.wustl.edu/~cs673/backUp/fall.1998.html Fall 1998]
* [http://cec.wustl.edu/~cs673/backUp/spring.1998.html Spring 1998]

==Previous Lab Meetings==
* [[Labmeeting Fall 2014|Fall 2014]]
* [[Labmeeting Summer 2014|Summer 2014]]
* [[Labmeeting Spring 2014|Spring 2014]]

2018-08-25T23:16:15Z

Dolvara:

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| __TOC__
|}

* '''Instructor:''' [http://www.cse.wustl.edu/~lu Prof. Chenyang Lu]
* '''Time: Friday at 4pm-5pm, Location: Jolley 224'''
* '''Google group:''' [http://groups.google.com/group/wu-systems-seminar google group]

This seminar examines fundamental and emerging concepts in concurrency and distribution by studying seminal papers and recent research results. Broad topics of interest include models of concurrency, mobile computing, parallel architectures, sensor networks, distributed algorithms, and specialized protocols. Each semester, the seminar emphasizes different themes reflecting the current research interests of the participants.

The theme of this semester's seminar is Wireless Sensor Networks. We will read and discuss papers from recent major conferences on mobile, wireless, and sensor networks and systems. These conferences include:

* SenSys ([http://sensys.acm.org])
* IPSN ([http://ipsn.acm.org])
* RTSS ([http://www.rtss.org/])
* RTAS ([http://www.rtas.org/])
* ICCPS ([http://www.iccps.org])
* Wireless Health ([http://www.wirelesshealth2013.org/])
* MobiCom ([http://www.sigmobile.org/mobicom/2013/])
* MobiSys ([http://www.sigmobile.org/mobisys/2013/])
* Sigcomm ([http://conferences.sigcomm.org/sigcomm/2013/])
* NSDI ([https://www.usenix.org/conference/nsdi14])
* SOSP ([http://http://sigops.org/sosp/sosp13/])
* OSDI ([https://www.usenix.org/conference/osdi14/])

=== ---August 31 ---===

Haoran

=== ---September 7---===

Dingwen

=== ---September 14 ---===

Yehan

=== ---September 21 ---===

Chao

=== ---September 28 ---===

Xi

=== ---October 5 ---===

Ruixuan

=== ---October 12 ---===

Chong

=== ---October 19 ---===

Dee

==Previous Semesters==
* [[Seminar Summer 2018|Summer 2018]]
* [[Seminar Spring 2018|Spring 2018]]
* [[Seminar Fall 2017|Fall 2017]]
* [[Seminar Summer 2017|Summer 2017]]
* [[Seminar Spring 2017|Spring 2017]]
* [[Seminar Fall 2016|Fall 2016]]
* [[Seminar Summer 2016|Summer 2016]]
* [[Seminar Spring 2016|Spring 2016]]
* [[Seminar Fall 2015|Fall 2015]]
* [[Seminar Summer 2015|Summer 2015]]
* [[Seminar Spring 2015|Spring 2015]]
* [[Seminar Fall 2014|Fall 2014]]
* [[Seminar Summer 2014|Summer 2014]]
* [[Seminar Spring 2014|Spring 2014]]
* [[Seminar Fall 2013|Fall 2013]]
* [[Seminar Summer 2013|Summer 2013]]
* [[Seminar Spring 2013|Spring 2013]]
* [[Seminar Fall 2012|Fall 2012]]
* [[Seminar Summer 2012|Summer 2012]]
* [[Seminar Spring 2012|Spring 2012]]
* [[Seminar Fall 2011|Fall 2011]]
* [[Seminar Summer 2011|Summer 2011]]
* [[Seminar Spring 2011|Spring 2011]]
* [[Seminar Fall 2010|Fall 2010]]
* [[Seminar Spring 2010|Spring 2010]]
* [[Seminar Fall 2009|Fall 2009]]
* [[Seminar Summer 2009|Summer 2009]]
* [[Seminar Spring 2009|Spring 2009]]
* [[Seminar Fall 2008|Fall 2008]]
* [[Seminar Summer 2008|Summer 2008]]
* [[Seminar Spring 2008|Spring 2008]]
* [[Fall 2007]]
* [[Summer 2007]]
* [[Spring 2007]]
* [[Fall 2006]]
* [[Spring 2006]]
* [[Fall 2005]]
* [[Spring 2005]]
* [[Fall 2004]]
* [[Spring 2004]]
* [[Fall 2003]]
* [[Spring 2003]]
* [[Fall 2002]]
* [http://userfs.cec.wustl.edu/~cs673/spring.2002.html Spring 2002]
* [http://userfs.cec.wustl.edu/~cs673/fall.2001.html Fall 2001]
* [http://userfs.cec.wustl.edu/~cs673/spring.2001.html Spring 2001]
* [[Fall 2000]]
* [http://userfs.cec.wustl.edu/~cs673/spring.2000.html Spring 2000]
* [http://cec.wustl.edu/~cs673/backUp/fall.1998.html Fall 1998]
* [http://cec.wustl.edu/~cs673/backUp/spring.1998.html Spring 1998]

==Previous Lab Meetings==
* [[Labmeeting Fall 2014|Fall 2014]]
* [[Labmeeting Summer 2014|Summer 2014]]
* [[Labmeeting Spring 2014|Spring 2014]]

CSE730x Research Seminar

2018-08-25T23:15:13Z

Dolvara:

Seminar Summer 2018

2018-08-25T23:11:14Z

2018-05-18T15:54:59Z

Dolvara: /* Status */

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| Contact: [mailto:dgunatilaka@wustl.edu Dolvara Gunatilaka]
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To facilitate advanced research in wireless sensor network technology, we are currently in the process of deploying a wireless sensor network testbed at Washington University in St. Louis. The testbed currently consists of 70 wireless sensor nodes (motes) placed throughout several office areas in Jolley Hall -- i.e., several grad student offices, the graduate student lounge, several labs, and conference rooms.

This document serves as an overview of the testbed setup and its current deployment. It is a living document in the sense that it will be updated as changes to the testbed continue to be made. In the end it will serve as a source of reference for anyone using the testbed to run sensornet related experiments.

Having a testbed of this size is important for a number of reasons:

* '''Only a handful of testbeds of this size exist in the world today.''' By being one of the first to have such a testbed, we will be able to conduct experiments that others have previously been unable to run. Our eventual goal is to make the testbed accessible through a simple web interface, opening it to users across the globe.
* '''Running large scale wireless sensor network experiments is hard.''' Programming a single mote can take up to five minutes depending on the size of the binary it is being programmed with. Without a testbed to streamline the process of programming a large number of motes, programming each mote individually can quickly become a significant bottleneck. Furthermore, as programming typically takes place by physically attaching a mote to your local machine, deploying them afterwards also takes a significant amount of time.

'''IMPORTANT:''' 
Please keep in mind that the motes deployed in the testbed only contain sensors for light, radiation, temperature, and humidity. There are no microphones or cameras, and there is no plan to EVER include such sensors in the future. The purpose of the testbed is primarily for measuring communication characteristics of the motes and not evaluating the sensitivity or accuracy of its sensors. If you have any privacy concerns about including the testbed in your office please direct any questions to [mailto:wsn@cse.wustl.edu wsn@cse.wustl.edu].

==Testbed Setup==
Our testbed deployment is based on the [http://www.tkn.tu-berlin.de/publications/papers/real04f-handziski.pdf TWIST architecture] originally developed by the telecommunications group ([http://www.tkn.tu-berlin.de/ TKN]) at the Technical University of Berlin. The acronmym TWIST stands for "TKN Wireless Indoor Sensor network Testbed". It is hierarchical in nature, consisting of three different levels of deployment: sensor nodes, microservers (i.e., Raspberry PIs), and a desktop class host/server machine. A high level view of this three tiered architecture can be seen in the figure below. [[Image:architecture_testbed.png|thumb|left|300px|Testbed Architecture]]
At the lowest tier, sensor nodes are placed throughout the physical environment in order to take sensor readings and/or perform actuation. They are connected to microservers at the second tier through USB cables. Messages can be exchanged between sensor nodes and microservers over this interface in both directions. At the third and final tier exists a switch and a dedicated server which connects to all of the microservers over an Ethernet backbone. The server machine is used to host, among other things, a database containing information about the different sensor nodes and the microservers they are connected to. This database minimally contains information about the connections that have been established between the sensor nodes and microservers, as well as their current locations. The server machine is also used to provide a workable interface between the testbed and any end-users. Users may log onto the server to gain access to the information contained in the testbed database, as well as exchange messages with nodes contained in the testbed. The entire TWIST architecture is based on cheap, off-the-shelf hardware and uses open-source software at every tier of its deployment.

Having such an architecture enables one to perform tasks not feasible in other WSN deployments. For example, debug messages from individual sensor nodes can be sent to the control station over the USB interface without interfering with a WSN application running in the network. The USB infrastructure essentially provides an out of band means for collecting important information from each node without clogging up the wireless channel and adversely affecting any experiments being run. This debug information can also be time stamped by the micorservers using NTP (Network Time Protocol) in order to gather statistics about what is going on at each individual point in the network at any given time.

Programming of sensor nodes in the testbed is also made easier using the three tiered architecture, as a user simply tells the control station which sensor nodes it would like to program, and the control station does the work of distributing this request to the proper microserver. Information about which sensor node is attached to which microserver can be obtained from the testbed database, and each request can be sent to the proper microserver using a dedicated thread of control. These requests can then be processed by each microserver in parallel, speeding up the time required to program the entire testbed significantly.

Individual sensor nodes in the testbed can also be disabled or enabled the USB interface. This capability allows node failures to be simulated in the testbed environment, as well as fine tune the density of the network itself when running certain types of experiments. The introduction of new nodes into the network can also be simulated by enabling nodes at specific times during the run of an experiment.

All of the features described above really boil down to just one thing. It is possible to run sophisticated experiments in the WSN testbed without ever having to physically change the layout of the testbed or interact with the individual sensor nodes that make it up. Everything is controllable from the central server, and scripts can be written to perform countless numbers of operations involving each of the capabilites described above.

==Existing Deployment==
Currently the testbed consists of 70 [http://www.xbow.com/Products/productdetails.aspx?sid=252 TelosB] motes placed throughout 3 floors of Jolley hall. The figure below shows the placement of these motes in the testbed. One to two motes are connected to each microserver, typically with one microserver per room.

[[Image:topology_testbed.png|thumb|left|800px|Existing deployment]]
 

==Testbed Software==

The testbed software has a client/server architecture, plus a set of user applications that interact with the wireless testbed. The client runs on the microservers and manages finding, programming, and communicating with the attached motes. The server coordinates the clients and the user applications. The user applications help the user to program, list, and communicate with motes in the system.

The client, server, and user application software has been written mostly in Python, with some performance-critical sections written in C. In addition, the server application interacts with a PostgreSQL database which lists the active microservers and motes. The PostgreSQL backend is also available for user applications to store experimental data.

===Startup===
The server software is automatically started as a Linux service on the testbed server machine. The client software is also installed as a service on the microservers but is not automatically started. A script is provided to the user which connects to the server and requests that the client be started on one or more microservers.

When the client service is brought up, it sends a status message to the server, which marks the microserver as "up" in the database. The microserver will also send messages listing the motes attached to its USB ports, which are likewise stored in the database.

===Programming===
To program a set of motes, the user runs the "program.py" script, passing it the program binary and a description of the motes to program. The user can select to program specific motes, all the motes attached to specific microservers, or the entire testbed.
The server converts this request into a list of targeted motes.

Once the set of motes has been determined, the server creates a binary file for each mote. The server copies the original binary, imprints it with the mote's network address (stored in the database), and moves the new binary to the home directory of the microserver the mote is attached to. The server then passes a request to the microserver to flash the binary onto the mote.

When the programming completes, the microserver informs the server whether it was successful or not. The server collects this status for every mote in the programming set, and informs the "program.py" script when the job is complete.

The slowest part of programming a mote is flashing the binary onto the mote. Because the flashing takes place on the microserver, we can program motes on different microservers in parallel, allowing us to program the entire testbed in the time it takes to program the motes on a single microserver.

===Serial Communication===
The testbed software allows the user to send and receive serial packets through the motes' USB ports. When a microserver discovers a new mote attached to one of its USB ports, it opens a connection to the mote's serial port. Whenever a new serial packet is ready, the microserver reads the packet and sends it to the testbed server over the Ethernet backbone. The testbed server forwards each packet to end-user applications which subscribe to this data. Conversely, users may send the server requests to write a serial packet to a specific mote, which the server will forward to the corresponding microserver.

The TinyOS SDK normally provides a "Serial Forwarder" component that allows PC applications to collect data from a locally-attached mote. To interact with the testbed instead, the user runs the provided "forwarder.py" script, which acts as a drop-in replacement for the Serial Forwarder. Thus, existing applications developed using the standard TinyOS SDK can be used on the testbed without modifications.

Users may optionally use a testbed-specific Python API in place of the "forwarder.py" script. This Python API offers new features which are not provided by the standard TinyOS SDK, such as the ability to remotely reboot motes.



==Status==

==Acknowledgments==
This work is supported by the NSF under a CRI grant (CNS-0708460) and an ITR grant (CCR-0325529).

* [[Equipment for course projects]]
* [[First Project on Zolertia Firefly]]
* [[Send data from server to node using serial forwarder]]
* [[Send data from node to server using serial forwarder]]
* [[TinyOS 2 Serial Communication Mechanism port on contiki]]
* [[CPSL serial communication protocol on testbed/contiki]]
* [[Glossy on contiki]]

CSE730x Research Seminar

2018-05-15T02:02:37Z

Dolvara: /* ---July 29 --- */

CSE730x Research Seminar

2018-05-04T21:57:32Z

Dolvara:

2018-02-28T20:38:31Z

Dolvara:

CSE730x Research Seminar

2018-02-13T15:36:01Z

Dolvara:

CSE730x Research Seminar

2018-02-01T19:26:34Z

Dolvara:

CSE730x Research Seminar

2018-02-01T19:26:00Z

Dolvara: /* ---March 8--- */

CSE730x Research Seminar

2018-02-01T17:59:05Z

Dolvara: /* ---January 25 --- */

CSE730x Research Seminar

2018-02-01T17:58:56Z

Dolvara: /* ---January 25 --- */