WCPS: Wireless Cyber-Physical Simulator

WCPS: Wireless Cyber-Physical Simulator

Wireless Structural Control (WSC) systems can play a crucial role in protecting civil infrastructure in the events of earth quakes and other natural disasters. Such systems represent an exemplary class of cyber-physical systems that perform close-loop control using real-time sensor data collected through wireless sensor networks. Existing WSC research usually employ wireless sensors installed on small lab structures, which cannot capture realistic delays and data loss in wireless sensor networks deployed on large civil structures and their impacts on structural control. The lack of realistic studies and tools that capture both the cyber (wireless) and physical (structures) aspects of WSC systems represent a hurdle for cyber-physical systems research for civil infrastructure. This paper advances the state of the art of WSC and Cyber-physical System through the following contributions. First, we developed the Wireless Cyber-Physical Simulator (WCPS), an integrated environment that combines realistic simulations of both wireless sensor networks and structures. WCPS integrates Simulink and TOSSIM, a state-of-the-art sensor network simulator featuring a realistic wireless model seeded by signal traces. Second, we performed two realistic case studies each matching a structural model with wireless traces collected from real-world environments. The building study combines a benchmark building model and wireless traces collected from a multi-story building. The bridge study combines the structural model of the Cape Girardeau bridge over the Mississippi River and wireless traces collected from a similar bridge (the Jindo Bridge) in Korea. These case studies shed lights on the challenges of WSC and the limitations of a traditional structural controller under realistic wireless conditions. Finally, we proposed a cyber-physical co-design approach to WSC that integrates a novel holistic scheduling scheme (for sensing, communication and control) and an Optimal Time Delay Controller (OTDC) that substantially improves structural control performance.

Software Setup

As an

Example sidebar code:

File:Example sidebar.png

Sidebar example

* navigation
** mainpage|mainpage
** Special:Recentchanges|Recent changes

MATLAB

The navigation bar can be split into sections, each with a heading of its own. The heading for each section is taken from the first-level list element ("navigation" and "new heading" in the example above).

If this text corresponds to the name of an interface message (an existing page of that title in the MediaWiki namespace), then the text of that page is used as a label; otherwise, the header title is used as-is.

Bug: no sidebar is shown in the Nostalgia skin (bug 10794).

TinyOS

Second-level list elements are links ("mainpage|mainpage" in the example above), where the format is:

** target|link text

target

The link target can be the name of an interface message (page in the MediaWiki namespace) or wiki page, or an external link. In either case, the link can be internal, interwiki, or external. In some cases (such as links with the "&" character), an interface message is necessary. The link target cannot be made dependent on the interface language set in the preferences.

PYTHON

By default, the sidebar consists of elements in this order: navigation, search, toolbox, languages. The order can be changed (in MediaWiki 1.13+) by adding special keywords (SEARCH, TOOLBOX and LANGUAGES) to

Software Environment Testing

That way you can easily translate these texts through the MediaWiki interface.

For more advanced translation, see Help:Extension:Translate/Unstructured element translation.

Wireless Network Modeling in WCPS

The sidebar can be fully customized by implementing JavaScript or Cascading Style Sheets, or by editing the PHP files directly. Before using these methods, note that:

• JavaScript is fragile: it will not work for users with JavaScript disabled, and scripts frequently fail in different browsers or skins.
• Editing the PHP files can easily cause unexpected errors, and your changes will be lost in the next update unless you manually change the new files.

Application Layer

Some pages should sometimes follow the content language, especially for multilingual sites. This can be controlled with the setting $wgForceUIMsgAsContentMsg. Each message overridden in this way must be explicitly given, for example to let the sidebar link to versions given by the content language for the main page and the portal page add the following to LocalSettings.php

code

<source lang="javascript">

$wgForceUIMsgAsContentMsg = array( 'mainpage', 'portal-url' );

</source>

Mac Layer

The toolbox, which appears under the search bar, is a dynamic element and cannot be easily customized without the use of skinning extensions (otherwise it requires programming in PHP.) If you still want to do so, you can copy skins/MonoBook.php, creating a new skin. You can then make a custom skin to generate these links in your preferred fashion.

Another javascript solution is below.

For this solution to work on the entire mediawiki site, this script has to be copied to MediaWiki:Common.js (MediaWiki:Common.js is available for Mediawiki 1.9 +).

For this solution to work only for a specific user, add this script to Special:Mypage/monobook.js (or another js-page, depending on your prefered skin).

Now simply configure which link should appear in which section. You also can remove some links if you want to.

code

<source lang="javascript">

function ModifySidebar(action, section, name, link) {

   try {
       switch (section) {
         case "languages":
           var target = "p-lang";
           break;
         case "toolbox":
           var target = "p-tb";
           break;
         case "navigation":
           var target = "p-navigation";
           break;
         default:
           var target = "p-" + section;
           break;
       }

       if (action == "add") {
           var node = document.getElementById(target)
                              .getElementsByTagName('div')[0]
                              .getElementsByTagName('ul')[0];

           var aNode = document.createElement('a');
           var liNode = document.createElement('li');

           aNode.appendChild(document.createTextNode(name));
           aNode.setAttribute('href', link);
           liNode.appendChild(aNode);
           liNode.className='plainlinks';
           node.appendChild(liNode);
       }

       if (action == "remove") {
           var list = document.getElementById(target)
                              .getElementsByTagName('div')[0]
                              .getElementsByTagName('ul')[0];

           var listelements = list.getElementsByTagName('li');

           for (var i = 0; i < listelements.length; i++) {
               if (listelements[i].getElementsByTagName('a')[0].innerHTML == name ||
                   listelements[i].getElementsByTagName('a')[0].href == link) {

                   list.removeChild(listelements[i]);
               }
           }
       }

   } catch(e) {
     // lets just ignore what's happened
     return;
   }

}

function CustomizeModificationsOfSidebar() {

   //adds Special:CategoryTree to toolbox
   ModifySidebar("add", "toolbox", "CategoryTree", "http://en.wikipedia.org/wiki/Special:CategoryTree");
   //removes Special:Upload from toolbox
   ModifySidebar("remove", "toolbox", "Upload file", "http://en.wikipedia.org/wiki/Special:Upload");

}

addOnloadHook(CustomizeModificationsOfSidebar);

</source>

Usage

function CustomizeModificationsOfSidebar() has to be customized for adding or removing links in specific sections:

ModifySidebar("action", "section", "name", "link");

parameter	value
action	add to add a link; remove to remove a link
section	navigation, toolbox, languages but also any other existing customized section; the given link will be added to or removed from this section
name	contains the text of the link
link	contains the URL of the link

restricting modifications to specific usergroups

If you want to restrict the modification of the links to a specific usergroup (e.g. bureaucrat), change <source lang="javascript">addOnloadHook(CustomizeModificationsOfSidebar);</source> to <source lang="javascript"> if (isArray(wgUserGroups)) {

   if (wgUserGroups.Contains('bureaucrat')) {
       addOnloadHook(CustomizeModificationsOfSidebar);
   }

} </source> and add <source lang="javascript"> function isObject(obj) {

   return typeof obj == "object" && obj != null;

}

function isArray(obj) {

   return isObject(obj) && obj.constructor.toString().indexOf("Array") != -1;

}

Array.prototype.Contains = function(element,strict) {

    for(i in this) {
         if(this[i] == element && !strict || this[i] === element) return true;
         }
    return false;
}

</source>

For restricting the modifications to IPs instead of a specific usergroup use <source lang="javascript"> if (!isArray(wgUserGroups)) {

       addOnloadHook(CustomizeModificationsOfSidebar);
}

</source>

Physical Layer

If you use the monobook-style and don't want to miss the expandable Menubar from e.g. Vector-Skin, paste the following code in MediaWiki:Common.js of your wiki. <source lang="javascript"> /////////////////////////////////////////////////////// // Codesnippet to make your sidebaritems expandable // // Use this code ONLY for monobook-Style. // ///////////////////////////////////////////////////////

$(document).ready(function(){

 //set the default expanded Items by their headline
 var defaultExpandItems= ['Navigation', 'Orga'];
 //set the basic-name for the cookies, which save the current state of expanding
 var expandCookieName = "disdance_project_wiki_nav_expanded_";

 var maxHeights=[]
 var expandeds=[];
 var labels=[];
 initNav();

});

function initNav(){

   $('#p-logo').css({'position':'relative', 'display':'block'});;
   $('.generated-sidebar h5,#p-tb h5 ').each(function(i){
      
         var id = $(this).parent().attr('id');           
         maxHeights[id]=$(this).next('div').height();
         var str = $(this).html();
         labels[id]=str;     
         
         if ($.cookie(expandCookieName+id)=='false'  ){               
               expandeds[id]=false;
               minimize( $(this));
               
        } else if ($.cookie(expandCookieName+id)=='true'  ){
               expandeds[id]=true;
               maximize( $(this));
       
        } else if (defaultExpandItems.indexOf(str)==-1){
               expandeds[id]=false;
               minimize( $(this));
        } else {
               expandeds[id]=true;
               maximize( $(this));
        }
        $(this).css({'cursor':'pointer'});
        $(this).click(toggleNav);
   });

}

function minimize(target){

   var id=$(target).parent().attr('id');
   //You can change the expires-parameter to save the Cookie longer/shorter than 7 days like in this Code
   $.cookie(expandCookieName+id,'false', { expires: 7});
   var str = labels[id]+"  ►";
   $(target).next('div').animate({'height':'0px'});
   $(target).html(str);    

}

function maximize(target){

   var id=$(target).parent().attr('id');
   //You can change the expires-parameter to save the Cookie longer/shorter than 7 days like in this Code
   $.cookie(expandCookieName+id,'true', { expires: 7});
   var str = labels[id]+"  ▼";
   var  newHeight = maxHeights[id];
   $(target).next('div').animate({'height':newHeight+'px'});
   $(target).html(str);    

}

function toggleNav(e){

   var id=$(e.target).parent().attr('id');
   expandeds[id]=!expandeds[id];
   if(expandeds[id]==true){ 
      maximize(e.target);
   } 
   else{ 
      minimize(e.target);
   }

}

/////////////////////////////////////////////////////// /////////////////////////////////////////////////////// </source>

References

• B. Li, Z. Sun, K. Mechitov, G. Hackmann, C. Lu, S. Dyke, G. Agha and B. Spencer, "Realistic Case Studies of Wireless Structural Control," ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS'13), April 2013.

• Z. Sun, B. Li, S.J. Dyke and C. Lu, "Evaluation of Performances of Structural Control Benchmark Problem with Time Delays from Wireless Sensor Network," Joint Conference of the Engineering Mechanics Institute and ASCE Joint Specialty Conference on Probabilistic Mechanics and Structural Reliability (EMI/PMC'12), June 2012.