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openwsn — Fri, 29 Feb 2008 00:17:11 CST

note0008 libopen

openwsn — Wed, 29 Aug 2007 02:46:24 CDT

@author zhangwei on 20070412
@libopen
@modified by xxx on 200704

LibOpen: The Interface/API To Sensor Networks

Q: what's LibOpen/libopen(libsink)
R:
libopen(libsink) is a API library that enable the developer to interact with the sensor networks easily. the develper can based their GUI worldview application or Internet-Sensor Networks gateway on libopen.

libopen should be portable easily. thus it can run on a host computer or a embedded device. the low level operating systems can vary from Windows, uCLinux/Linux to other embedded RTOS.

however, in the current implmentation, it can only run on Windows OS. but we introduced layer design and implementation so that it can be easily ported to other systems.

Q: architecture of libopen/libsink?
R:
libopen adopts layer design

Top Layer: all kinds of applications(they are not part of libopen)(application layer)
Middle Layer: core logic of libopen (service layer)
Bottom Layer: abstraction layer (hal layer)

Application: [GUI Worldview] [Internet-Sensor Networks Gateway] [Others...]
------------------------------------------------------------------------
|||||||||||||||
Middle Layer: [libopen services] <---- thread or evolve() driven
|||||||||||||||
------------------------------------------------------------------------
Bottom Layer: [Simulated Driver] [Rs232 Driver] [USB Driver] [Socket Network Driver]
| | | |
Harddisk WSN WSN other libopen gateway

in the architecture design, libopen contains a simulated driver. this driver will generate random wsn data for testing use. thus you can develope/test your upper layers from "libopen" to even "worldview". it can also replace the random data by loading data files from harddisk. these data files may from the real measurement of wsn or generated randomly.

libopen service API include driver selection and configure, raw frame/packet read/write, binary xml data interpretation, data logging control.

the Internet-Sensor Networks Gateway is a socket server running on the same device with libopen. so you can connect to this server in a remote host computer. while the "socket network driver" is a client helping to to connect "gateway server". different to the other service API, the gateway server must solve the problem of concuurent visiting of libopen (i had not think more about it yet!).

some one may want a web interface for wsn. the web interface should be based on the gateway server.

20070524
//----------------------------------------------------------------------------
// @author zhousongli
// @state developing
//
// @modified by zhangwei on 20070524
// the architecture of libopen
//
// TQueryEngine................................
// | load from Database or File
// TOpenNetwork..............TSimuNetwork-----
// | |
// |THostDrivenRouting.......Log to Database or File
// ---------------
// | |
// TSioComm TSioComm
// TUart TUsb
//
// there're some key objects in libopen:
// o TUart
// exposed to application developer
// the user can use this object to configure the Rs232 parameter or Usb device
// parameter. generally, the user will not do this because we have already
// set their default configurations.
// o TUsb (not developed now)
// similar to TUsb
// o TSioComm
// on top of TUart
// provide frame assemble and disassemble.
// the payload in each frame can be mapped to an TQueryDataItem object.
//
// o TOpenRouter
// an libopen/host driven routing protocol. query based.
// this protocol enable you can communicate with remote nodes in the network
// by multi-hop forwarding.
//
// o TOpenNetwork
// exposed to application developer.
// provide an interface for the upper level developer to interact with the
// sensor network. it's an abstraction of the whole network.
//
// o TQueryEngine
// exposed to application developer.
// on top of TOpenNetwork interface
// user query command interpretation and execution
//
// o TSimuNetwork
// exposed to application developer.
// has almost the same interface of TOpenNetwork
// used for simulation only
//
// there're also some utility object
// o TBinaryXml
// ease the manipulation of payload data.
// o TQueryDataItem
// represents a data item. data item : packet = 1 : 1
// o TQueryDataSet
// is an list of the TQueryDataItem
//
//----------------------------------------------------------------------------

20070525
Q: how to learn/understand libopen fast if i'm a new developer?
R:
If you are new to "libopen" developing, you should aware that:

libopen is essentially composed by four separate parts:
- TOpenNetwork ( related to TOpenRouter, TSioComm, TUart..)
it's the core of libopen
- TQueryEngine
query parser and execution
it's based on TOpenNetwork interface.
- TSimuNetwork
share the same interface with TOpenNetwork
you can configure the network object to "SIMULATION" mode.
- TBinaryXml
a utility help you assemble/disassemble data in payload buffer.

you should review the following modules first:
svc_netnode, svc_network
svc_queryengine, svc_dataset
svc_netsimu
rtl_binaryxml

Q: interface design(maybe changed in the future. pls refer to the source code for updated)
R:
high level data service based on binaryxml
this interface enable the upper level application to query the sensor data of any time at any location and any time.

svc_querynode( nodeid, sensor type, out sensor value (
svc_querylocation( location, sensor type, out sensor value, out probability )
svc_query( TQueryCondition * cond, TRangeData * data )

high level data service such as binaryxml analyzing
svc_binaryxml_getfirst
svc_binaryxml_getnext
svc_binaryxml_getprev
svc_binaryxml_getlast

raw data service interface
svc_create
svc_free
svc_construct
svc_destroy
svc_configure
svc_relation( driver )
svc_read
svc_write
svc_rawread
svc_rawwrite

svc_dbgen generate a random data logging database file
svc_dbopen connect to a existed database file
svc_dbclose
svc_dbread read one data item from the database it's usually a binaryxml format array
svc_dbwrite
svc_dbload load a database file into the memory for further processing
svc_dbsave

driver manipulation interface:
svc_relation
svd_dm_create
svd_dm_free
svd_dm_read
svd_dm_rawread
svd_dm_write
svd_dm_rawwrite

xxx_create
xxx_free
xxx_read
xxx_write
xxx为driver缩写，包括rs232, usb, socket, webserv

MDP: OpenM2M / OpenWSN MAPI

Section：MAPI和计算机监控程序参考实现

所有前述工作只是描述node和网络的工作。但是在连接sink node的计算上，还有较大的工作量。我们需要在这里提供一套API，使得computer上的程序可以方便的访问M2M network的功能并进行监控。这套编程接口称之为M2M application programming interface (MAPI)。并在这套API基础上提供一个监控程序的参考实现。

MAPI功能：
下行数据发送（命令，配置数据和程序更新等）
上行数据接收
网络管理
网络编程

MAPI包含两个层次：
底层：基本控制
中层：PC Service（作为独立进程运行）
高层：高层方便使用的API

底层：
mhal_openusb/sio/Ethernet
mhal_close
mhal_read
mhal_write
mhal_rawread
mhal_rawwrite

中层 m2m_service (可以运行在PC或embedded system)
作为一个独立的进程运行，功能如下：
－将收到的所有数据都写入到本地database中，格式（location, timestamp, data）
其中，location可以是符号信息，可以是绝对位置，可以是nodeid
data则具有{attribute, value}形式
— 提供callback机制，允许高层决定对收到的数据如何处理
－提供filter方式允许对收到的数据进行过滤，以减小数据量
该service要一直作为一个daemon或者system service运行，无GUI界面，且不论GUI界面启动与否都应运行。

－提供从本地cache/database中读取数据的API，并且在读数据的时候也支持 filter模
式，以降低数据量
o 提供执行网络查询功能
o 提供设置网络filter功能

高层：应用（不规定）
以利用中层API为主，与中层主要是通过数据库进行交互。
为了方便开发，也提供一套简单的API方便对数据库中的数据进行汇总输出，如query_cube, predict等，基本上以分析型API为主。
可以构造特殊的命令包，发给中层service，令其执行之。这些命令往往会影响到网络的状态。
msvc_open
msvc_close
msvc_read
msvc_write
msvc_filter

主监控系统
以地图的方式，提供位置轴(空间XYZ坐标和接点ID号)和时间轴供用户选择，让用户可以方便的选择某个区域在某个时间段内的数据。
以查询方式向service查询最新收到的数据，并且显示在GUI画面上。查询周期可以设置，一般不小于0.5秒，以免得service负荷过重，影响了处理性能。
由于采用网络通信手段，主监控软件和service可以运行在不同的device上，增加了灵活性，且可以运行多个主监控软件，同时连接到一个service上。如果service开放的是80或8080端口，则我们还可以在Internet上连接到service获取数据。这里不推荐web service方案，因为后者过于笨重，效率太低，所以我们宁肯将网络通信直接构建在socket通信基础上。

ema

openwsn — Wed, 29 Aug 2007 02:11:31 CDT

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test2

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test

openwsn — Wed, 29 Aug 2007 02:02:41 CDT

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