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  • Multiplying complex with constant in C++

    - by Atilla Filiz
    The following code fails to compile #include <iostream> #include <cmath> #include <complex> using namespace std; int main(void) { const double b=3; complex <double> i(0, 1), comp; comp = b*i; comp=3*i; return 0; } with error: no match for ‘operator*’ in ‘3 * i’ What is wrong here, why cannot I multiply with immediate constants?

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  • Creating Java Neural Networks

    - by Tori Wieldt
    A new article on OTN/Java, titled “Neural Networks on the NetBeans Platform,” by Zoran Sevarac, reports on Neuroph Studio, an open source Java neural network development environment built on top of the NetBeans Platform. This article shows how to create Java neural networks for classification.From the article:“Neural networks are artificial intelligence (machine learning technology) suitable for ill-defined problems, such as recognition, prediction, classification, and control. This article shows how to create some Java neural networks for classification. Note that Neuroph Studio also has support for image recognition, text character recognition, and handwritten letter recognition...”“Neuroph Studio is a Java neural network development environment built on top of the NetBeans Platform and Neuroph Framework. It is an IDE-like environment customized for neural network development. Neuroph Studio is a GUI that sits on top of Neuroph Framework. Neuroph Framework is a full-featured Java framework that provides classes for building neural networks…”The author, Zoran Sevarac, is a teaching assistant at Belgrade University, Department for Software Engineering, and a researcher at the Laboratory for Artificial Intelligence at Belgrade University. He is also a member of GOAI Research Network. Through his research, he has been working on the development of a Java neural network framework, which was released as the open source project Neuroph.Brainy stuff. Read the article here.

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  • Encode complex number as RGB pixel

    - by Vi
    How is it better to encode a complex number into RGB pixel and vice versa? Probably (logarithm of) an absolute value goes to brightness and an argument goes to hue. Desaturated pixes should receive randomized argument in reverse transformation. Something like: 0 - (0,0,0) 1 - (255,0,0) -1 - (0,255,255) 0.5 - (128,0,0) i - (255,255,0) -i - (255,0,255) (0,0,0) - 0 (255,255,255) - e^(i * random) (128,128,128) - 0.5 * e^(i *random) (0,128,128) - -0.5 Are there ready-made formulas for that?

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  • complex sql which runs extremely slow when the query has order by clause

    - by basit.
    I have following complex query which I need to use. When I run it, it takes 30 to 40 seconds. But if I remove the order by clause, it takes 0.0317 sec to return the result, which is really fast compare to 30 sec or 40. select DISTINCT media.* , username from album as album , album_permission as permission , user as user, media as media where ((media.album_id = album.album_id and album.private = 'yes' and album.album_id = permission.album_id and (permission.email = '' or permission.user_id = '') ) or (media.album_id = album.album_id and album.private = 'no' ) or media.album_id = '0' ) and media.user_id = user.user_id and media.media_type = 'video' order by media.id DESC LIMIT 0,20 The id on order by is primary key which is indexed too. So I don't know what is the problem. I also have album and album permission table, just to check if media is public or private, if private then check if user has permission or not. I was thinking maybe that is causing the issue. What if I did this in sub query, would that work better? Also can someone help me write that sub query, if that is the solution? If you can't help write it, just at least tell me. I'm really going crazy with this issue.. SOLUTION MAYBE Yes, I think sub-query would be best solution for this, because the following query runs at 0.0022 seconds. But I'm not sure if validation of an album would be accurate or not, please check. select media.*, username from media as media , user as user where media.user_id = user.user_id and media.media_type = 'video' and media.id in (select media2.id from media as media2 , album as album , album_permission as permission where ((media2.album_id = album.album_id and album.private = 'yes' and album.album_id = permission.album_id and (permission.email = '' or permission.user_id = '')) or (media.album_id = album.album_id and album.private = 'no' ) or media.album_id = '0' ) and media.album_id = media2.album_id ) order by media.id DESC LIMIT 0,20

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  • Data Networks Visualized via Light Paintings [Video]

    - by ETC
    All around you are wireless data networks: cellular networks, Wi-Fi networks, a world of wireless communication. Check out this awesome video of network signals mapped over a cityscape. What would happen if you made a device that allowed you to map signal strength onto film? In the following video electronics tinkerers craft an LED meter and use it to paint onto long exposure photographs with phenomenal results. Immaterials: light painting Wi-Fi [via Make] Latest Features How-To Geek ETC Learn To Adjust Contrast Like a Pro in Photoshop, GIMP, and Paint.NET Have You Ever Wondered How Your Operating System Got Its Name? Should You Delete Windows 7 Service Pack Backup Files to Save Space? What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions Add a “Textmate Style” Lightweight Text Editor with Dropbox Syncing to Chrome and Iron Is the Forcefield Really On or Not? [Star Wars Parody Video] Google Updates Picasa Web Albums; Emphasis on Sharing and Showcasing Uwall.tv Turns YouTube into a Video Jukebox Early Morning Sunrise at the Beach Wallpaper Data Networks Visualized via Light Paintings [Video]

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  • ASP.MVC 1.0 complex ViewModel not populating on Action

    - by Graham
    Hi, I'm 3 days into learning MVC for a new project and i've managed to stumble my way over the multitude of issues I've come across - mainly about something as simple as moving data to a view and back into the controller in a type-safe (and manageable) manner. This is the latest. I've seen this reported before but nothing advised has seemed to work. I have a complex view model: public class IndexViewModel : ApplicationViewModel { public SearchFragment Search { get; private set; } public IndexViewModel() { this.Search = new SearchFragment(); } } public class SearchFragment { public string ItemId { get; set; } public string Identifier { get; set; } } This maps to (the main Index page): %@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<IndexViewModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server"> <% Html.BeginForm("Search", AvailableControllers.Search, FormMethod.Post); %> <div id="search"> <% Html.RenderPartial("SearchControl", Model.Search); %> </div> <% Html.EndForm(); %> </asp:Content> and a UserControl: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<SearchFragment>" %> <p> <label for="itemId"> <%= Html.Resource("ItemId") %></label> <%= Html.TextBox("itemId", Model.ItemId)%> </p> <p> <label for="title"> <%= Html.Resource("Title") %></label> <%= Html.TextBox("identifier", Model.Identifier)%> </p> <p> <input type="submit" value="<%= Html.Resource("Search") %>" name="search" /> </p> This is returned to the following method: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Search(IndexViewModel viewModel) { .... } My problem is that when the view model is rehydrated from the View into the ViewModel, the SearchFragment elements are null. I suspect this is because the default model binder doesn't realise the HTML ItemId and Identifier elements rendered inline in the View map to the SearchFragment class. When I have two extra properties (ItemId and Identifier) in the IndexViewModel, the values are bound correctly. Unfortunately, as far as I can tell, I must use the SearchFragment as I need this to strongly type the Search UserControl... as the control can be used anywhere it can operate under any parent view. I really don't want to make it use "magic strings". There's too much of that going on already IMO. I've tried prefixing the HTML with "Search." in the hope that the model binder would recognise "Search.ItemId" and match to the IndexViewModel "Search" property and the ItemId within it, but this doesn't work. I fear I'm going to have to write my own ModelBinder to do this, but surely this must be something you can do out-of-the-box?? Failing that is there any other suggestions (or link to someone who has already done this?) Here's hoping....

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  • Why is Perl's Math::Complex taking up so much time when I try acos(1)?

    - by synapz
    While trying to profile my Perl program, I find that Math::Complex is taking up a lot of time with what looks like some kind of warning. Also, my code shouldn't have any complex numbers being generated or used, so I am not sure what it is doing in Math::Complex, anyway. Here's the FastProf output for the most expensive lines: /usr/lib/perl5/5.8.8/Math/Complex.pm:182 1.55480 276232: _cannot_make("real part", $re) unless $re =~ /^$gre$/; /usr/lib/perl5/5.8.8/Math/Complex.pm:310 1.01132 453641: sub cartesian {$_[0]->{c_dirty} ? /usr/lib/perl5/5.8.8/Math/Complex.pm:315 0.97497 562188: sub set_cartesian { $_[0]->{p_dirty}++; $_[0]->{c_dirty} = 0; /usr/lib/perl5/5.8.8/Math/Complex.pm:189 0.86302 276232: return $self; /usr/lib/perl5/5.8.8/Math/Complex.pm:1332 0.85628 293660: $self->{display_format} = { %display_format }; /usr/lib/perl5/5.8.8/Math/Complex.pm:185 0.81529 276232: _cannot_make("imaginary part", $im) unless $im =~ /^$gre$/; /usr/lib/perl5/5.8.8/Math/Complex.pm:1316 0.78749 293660: my %display_format = %DISPLAY_FORMAT; /usr/lib/perl5/5.8.8/Math/Complex.pm:1335 0.69534 293660: %{$self->{display_format}} : /usr/lib/perl5/5.8.8/Math/Complex.pm:186 0.66697 276232: $self->set_cartesian([$re, $im ]); /usr/lib/perl5/5.8.8/Math/Complex.pm:170 0.62790 276232: my $self = bless {}, shift; /usr/lib/perl5/5.8.8/Math/Complex.pm:172 0.56733 276232: if (@_ == 0) { /usr/lib/perl5/5.8.8/Math/Complex.pm:316 0.53179 281094: $_[0]->{'cartesian'} = $_[1] } /usr/lib/perl5/5.8.8/Math/Complex.pm:1324 0.48768 293660: if (@_ == 1) { /usr/lib/perl5/5.8.8/Math/Complex.pm:1319 0.44835 293660: if (exists $self->{display_format}) { /usr/lib/perl5/5.8.8/Math/Complex.pm:1318 0.40355 293660: if (ref $self) { # Called as an object method /usr/lib/perl5/5.8.8/Math/Complex.pm:187 0.39950 276232: $self->display_format('cartesian'); /usr/lib/perl5/5.8.8/Math/Complex.pm:1315 0.39312 293660: my $self = shift; /usr/lib/perl5/5.8.8/Math/Complex.pm:1331 0.38087 293660: if (ref $self) { # Called as an object method /usr/lib/perl5/5.8.8/Math/Complex.pm:184 0.35171 276232: $im ||= 0; /usr/lib/perl5/5.8.8/Math/Complex.pm:181 0.34145 276232: if (defined $re) { /usr/lib/perl5/5.8.8/Math/Complex.pm:171 0.33492 276232: my ($re, $im); /usr/lib/perl5/5.8.8/Math/Complex.pm:390 0.20658 128280: my ($z1, $z2, $regular) = @_; /usr/lib/perl5/5.8.8/Math/Complex.pm:391 0.20631 128280: if ($z1->{p_dirty} == 0 and ref $z2 and $z2->{p_dirty} == 0) { Thanks for any help!

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  • Complex String Processing - well complex to me

    - by percent20
    I am calling a web service and all I get back is a giant blob of text. I am left to process it myself. Problem is not all lines are necessarily the same. They each have 2 or 3 sections to them and they are similar. Here are the most common examples text1 [text2] /text3/ text1/test3 text1[text2]/text3 text1 [text2] /text /3 here/ I am not exactly sure how to approach this problem. I am not too good at doing anything advanced as far as manipulating strings. I was thinking using a regular expression might work, but not too sure on that either. If I can get each of these 3 sections broken up it is easier from there to do the rest. its just there doesn't seem to be any uniformity to the main 3 sections that I know how to work with.

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  • Application to organize / manage installed networks

    - by vicmp3
    I was wondering if there is a Application where you can organize networks. I mean if you have installed some networks you have to note every pc's name, his ip-address and so on. Is there a Application where you can manage it? I saw the monitoring tools but that is not exactly what I'm looking for. Maybe I didnt explain me well, after all my englis his not so good :) For example if I install many different networks I write in a book how I configured them. I write pc-name ip-address ip-gateway ip-broadcast and so on for each network. It will be great if I can do it in a program to organize it well, and for example it gives me a node view of the network.

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  • Organic Business Networks -Don't Miss This Webcast!

    - by Michael Snow
    TUNE IN TODAY!! Oracle Social Business Thought Leaders Webcast Series Thursday, June 21st 10am PST  Organic Business Networks: Doing Business in a Hyper-Connected World Organic business networks connect people, data, content, and IT systems in a flexible, self-optimizing, self-healing, self-configuring and self-protecting system. Join us for this webcast and hear examples of how businesses today can effectively utilize the interconnectedness of emerging business information environments, adapt to changing conditions, and leverage assets effectively to thrive in a hyper-connected, globally competitive, information driven world. Listen as Featured Speaker, Michael Fauscette, GVP, Software Business Solutions, IDC, discusses: Emerging trends in social business that are driving transformative changes today The dynamic characteristics that make up social, collaborative, and connected enterprises Effective ways that technology combined with culture and process provide unique competitive advantage through new organic networked business models. Register now for the fifth Webcast in the Social Business Thought Leaders Series,“Organic Business Networks: Doing Business in a Hyper-Connected World.”

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  • Why does C++ mandate that complex only be instantiated for float, double, or long double?

    - by templatetypedef
    According to the C++ ISO spec, §26.2/2: The effect of instantiating the template complex for any type other than float, double or long double is unspecified. Why would the standard authors explicitly add this restriction? This makes it unspecified, for example, what happens if you make complex<int> or a complex<MyCustomFixedPointType> and seems like an artificial restriction. Is there a reason for this limitation? Is there a workaround if you want to instantiate complex with your own custom type? I'm primarily asking this question because of this earlier question, in which the OP was confused as to why abs was giving bizarre outputs for complex<int>. That said, this still doesn't quite make sense given that we also might want to make complex numbers out of fixed-points types, higher-precision real numbers, etc. Thanks!

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  • Hyper-V for Developers Part 1 Internal Networks

    Over the last year, weve been working with Microsoft to build training and demo content for the next version of Office Communications Server code-named Microsoft Communications Server 14.  This involved building multi-server demo environments in Hyper-V, getting them running on demo servers which we took to TechEd, PDC, and other training events, and sometimes connecting the demo servers to the show networks at those events.  ITPro stuff that should scare the hell out of a developer! It can get ugly when I occasionally have to venture into ITPro land.  Lets leave it at that. Having gone through this process about 10 to 15 times in the last year, I finally have it down.  This blog series is my attempt to put all that knowledge in one place if anything, so I can find it somewhere when I need it again.  Ill start with the most simple scenario and then build on top of it in future blog posts. If youre an ITPro, please resist the urge to laugh at how trivial this is. Internal Hyper-V Networks Lets start simple.  An internal network is one that intended only for the virtual machines that are going to be on that network it enables them to communicate with each other. Create an Internal Network On your host machine, fire up the Hyper-V Manager and click the Virtual Network Manager in the Actions panel. Select Internal and leave all the other default values. Give the virtual network a name, and leave all the other default values. After the virtual network is created, open the Network and Sharing Center and click Change Adapter Settings to see the list of network connections. The only thing I recommend that you do is to give this connection a friendly label, e.g. Hyper-V Internal.  When you have multiple networks and virtual networks on the host machines, this helps group the networks so you can easily differentiate them from each other.  Otherwise, dont touch it, only bad things can happen. Connect the Virtual Machines to the Internal Network Im assuming that you have more than 1 virtual machine already configured in Hyper-V, for example a Domain Controller, and Exchange Server, and a SharePoint Server. What you need to do is basically plug in the network to the virtual machine.  In order to do this, the machine needs to have a virtual network adapter.  If the VM doesnt have a network adapter, open the VMs Settings and click Add Hardware in the left pane.  Choose the virtual network to which to bind the adapter to. If you already have a virtual network adapter on the VM, simply connect it to the virtual network. Assign IP Addresses to the Virtual Machines on the Internal Network Open the Network and Sharing Center on your VM, there should only be 1 network at this time.  Open the Properties of the connection, select Internet Protocol Version 4 (TCP/IPv4) and hit Properties. In this environment, Im assigning IP addresses as 192.168.0.xxx.  This particular VM has an IP address of 192.168.0.40 with a subnet mask of 255.255.255.0, and a DNS Server of 192.168.0.18.  DNS is running on the Domain Controller VM which has an IP address of 192.168.0.18. Repeat this process on every VM in your environment, obviously assigning a unique IP address to each.  In an environment with a domain controller, you should now be able to ping the machines from each other. What Next? After completing this process, heres what you still cannot do: Access the internet from any of the VMs Remote desktop to a VM from the host Remote desktop to a VM over the network In the next post, well take a look configuring an External network adapter on the virtual machines.  Well then build on top of that so that you can RDP into the VMs from the host machine and over the network.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Complex query making site extremely slow

    - by Basit
    select SQL_CALC_FOUND_ROWS DISTINCT media.*, username from album as album, album_permission as permission, user as user, media as media , word_tag as word_tag, tag as tag where ((media.album_id = album.album_id and album.private = 'yes' and album.album_id = permission.album_id and (permission.email = '' or permission.user_id = '') ) or (media.album_id = album.album_id and album.private = 'no' ) or media.album_id = '0' ) and media.status = '1' and media.user_id = user.user_id and word_tag.media_id = media.media_id and word_tag.tag_id = tag.tag_id and tag.name in ('justin','bieber','malfunction','katherine','heigl','wardrobe','cinetube') and media.media_type = 'video' and media.media_id not in ('YHL6a5z8MV4') group by media.media_id order by RAND() #there is limit too, by 20 rows.. i dont know where to begin explaining about this query, but please forgive me and ask me if you have any question. following is the explanation. SQL_CALC_FOUND_ROWS is calculating how many rows are there and will be using for pagination, so it counts total records, even tho only 20 is showing. DISTINCT will stop the repeated row to display. username is from user table. album, album_permission. its checking if album is private and if it is, then check if user has permission, by user_id. i think rest is easy to understand, but if you need to know more about it, then please ask. im really frustrated by this query and site is very slow or not opening sometimes cause of this query. please help

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  • Complex data types in WCF?

    - by Hojou
    I've run into a problem trying to return an object that holds a collection of childobjects that again can hold a collection of grandchild objects. I get an error, 'connection forcibly closed by host'. Is there any way to make this work? I currently have a structure resembling this: pseudo code: Person: IEnumerable<Order> Order: IEnumberable<OrderLine> All three objects have the DataContract attribute and all public properties i want exposed (including the IEnumerable's) have the DataMember attribute. I have multiple OperationContract's on my service and all the methods returning a single object OR an IEnumerable of an object works perfectly. It's only when i try to nest IEnumerable that it turns bad. Also in my client service reference i picked the generic list as my collection type. I just want to emphasize, only one of my operations/methods fail with this error - the rest of them work perfectly. EDIT (more detailed error description): [SocketException (0x2746): An existing connection was forcibly closed by the remote host] [IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.] [WebException: The underlying connection was closed: An unexpected error occurred on a receive.] [CommunicationException: An error occurred while receiving the HTTP response to http://myservice.mydomain.dk/MyService.svc. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details.] I tried looking for logs but i can't find any... also i'm using a WSHttpBinding and an http endpoint.

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  • SQL complex Question

    - by santanu
    Hello All, I need to find a function. the scenario is : I have 2 table. 1. news table 2. news_comment table need to find the most commented 20 news. the news_comment table has the relationship with the news table Thank you

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  • Parsing Complex Text File with C#

    - by David
    Hello, I need to parse a text file that has a lot of levels and characters. I've been trying different ways to parse it but I haven't been able to get anything to work. I've included a sample of the text file I'm dealing with. Any suggestions on how I can parse this file? I have denoted the parts of the file I need with TEXTINEED. (bean name: 'TEXTINEED context: (list '/text '/content/home/left-nav/text '/content/home/landing-page) type: '/text/types/text module: '/modules/TEXTINEED source: '|moretext| ((contents (list (list (bean type: '/directory/TEXTINEED ((directives (bean ((chartSize (list 600 400)) (showCorners (list #f)) (showColHeader (list #f)) (showRowHeader (list #f))))))) (bean type: '/directory/TEXTINEED ((directives (bean ((displayName (list "MTD")) (showCorners (list #f)) (showColHeader (list #f)) (showRowLabels (list #f)) (hideDetailedLink (list #t)) (showRowHeader (list #f)) (chartSize (list 600 400))))))) (bean type: '/directory/TEXTINEED ((directives (bean ((displayName (list "QTD")) (showCorners (list #f)) (showColHeader (list #f)) (showRowLabels (list #f)) (hideDetailedLink (list #t)) (showRowHeader (list #f)) (chartSize (list 600 400)))))))) Thanks!

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  • SQL Complex Select - Trouble forming query

    - by JoshSpacher
    I have three tables, Customers, Sales and Products. Sales links a CustomerID with a ProductID and has a SalesPrice. select Products.Category, AVG(SalePrice) from Sales inner join Products on Products.ProductID = Sales.ProductID group by Products.Category This lets me see the average price for all sales by category. However, I only want to include customers that have more than 3 sales records or more in the DB. I am not sure the best way, or any way, to go about this. Ideas?

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  • Create a complex SQL query?

    - by mazzzzz
    Hey guys, I have a program that allows me to run queries against a large database. I have two tables that are important right now, Deposits and withdraws. Each contains a history of every user. I need to take each table, add up every deposit and withdraws (per user), then subtract the withdraws from the deposits. I then need to return every user whos result is negative (aka they withdrew more then they deposited). Is this possible in one query? Example: Deposit Table: |ID|UserName|Amount| |1 | Use1 |100.00| |2 | Use1 |50.00 | |3 | Use2 |25.00 | |4 | Use1 | 5.00 | WithDraw Table: |ID|UserName|Amount| |2 | Use2 | 5.00 | |1 | Use1 |100.00| |4 | Use1 | 5.00 | |3 | Use2 |25.00 | So then the result would output: |OverWithdrawers| | Use2 | Is this possible (I sure don't know how to do it)? Thanks for any help, Max

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  • How can I prioritize wireless networks with network-manager

    - by kynan
    Mostly I use my laptop in an environment where different wireless networks are available and I would like to preferably connect to one of those and only fall back to the other one if that one is not available. Is there any way of prioritizing which wireless networks network-manager preferably connects to? The only workaround I found so far was unchecking Connect Automatically in the options and re-enabling it when my preferred network is not available.

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  • Problem connecting to certain wifi networks

    - by Romas
    I'm using lenovo u300s (it has Intel Centrino Wireless-N 1030 card), and I can connect to wireless network at home with no problem, but I can not connect to any networks at my university. I'm not sure if it's the case but most of university networks are open and you need to sign up your username as you enter browser. There is also an eudoroam network, but I can not connect to it either. Any suggestions? Yes I have the latest ubuntu version.

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  • Broadcasted networks appear cached with netsh? [on hold]

    - by Joe
    We have a company mandate to hide certain windows functions. I'm working on a company application which will allow my users to configure WiFi networks. The app is scanning broadcasted networks using: "netsh wlan show networks" it will return networks that have been turned off. For example: I will run the command and then unplug my wireless router with the SSID "Netgear". For several minutes after turning off the network, the show networks command will continue to return "Netgear". Does anyone know where this gets cached, how to clear it out, or how to force a fresh scan of "netsh wlan show networks"? Thanks all, J

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  • Numpy: Creating a complex array from 2 real ones?

    - by Duncan Tait
    I swear this should be so easy... Why is it not? :( In fact, I want to combine 2 parts of the same array to make a complex array: Data[:,:,:,0] , Data[:,:,:,1] These don't work: x = np.complex(Data[:,:,:,0], Data[:,:,:,1]) x = complex(Data[:,:,:,0], Data[:,:,:,1]) Am I missing something? Does numpy not like performing array functions on complex numbers? Here's the error: TypeError: only length-1 arrays can be converted to Python scalars Cheers

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  • Wireless networks are not detected at start up in Ubuntu 12.04

    - by Kanhaiya Mishra
    I have recently (three four days ago) installed Ubuntu 12.04 via windows installer i.e. wubi.exe. After the installation completed wireless and Ethernet were both working well. But after restart wireless networks didn't show up while in the network manager both networking and wireless were enabled. Though sometimes after boot it did show the networks available but very rarely. So I went through various posts regarding wireless issues in Ubuntu 12.04 and tried so many things but ended up in nothing satisfactory. I have Broadcom 4313 LAN network controller and brcmsmac driver. Then relying on some suggestions I tried to install bcm-wl driver but couldn't install due to some error in jockeyl.log file. Then i tried fresh installation of the same driver but still could resolve the startup issues with wireless. Then again I reinstalled Ubuntu inside windows using wubi installer. This time again same problem occurred after boot. But this time I successfully installed wl driver before disturbing file-system files of Ubuntu. But again the same issue. This time I noticed some new things: If I inserted Ethernet/LAN cable before startup then wireless networks are available and of course LAN(wired) networks also work. but if i don't plug in cable before startup and then plug it after startup then it didn't detect Ethernet network neither wireless. So I haven't noticed it before that LAN along with wifi also doesn't work after startup. But if i suspend the session and make it sleep and again login then it worked. I tried it every time that WLAN worked perfectly. But still i m unable to resolve that startup problem. Each time i boot first I have to suspend it once then only networks are available. It irritates me each time i reboot/boot my lappy. So please help out of this problem. Any ideas/help regarding this issue would be highly appreciated. Some of the commands that i run gave following results: # lspci 00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 12) 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 12) 00:16.0 Communication controller: Intel Corporation 5 Series/3400 Series Chipset HECI Controller (rev 06) 00:1a.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 06) 00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 06) 00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 06) 00:1c.5 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 6 (rev 06) 00:1d.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a6) 00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 06) 00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 6 port SATA AHCI Controller (rev 06) 00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06) 00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 06) 03:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) 04:00.0 Ethernet controller: Atheros Communications Inc. AR8152 v1.1 Fast Ethernet (rev c1) ff:00.0 Host bridge: Intel Corporation Core Processor QuickPath Architecture Generic Non-core Registers (rev 02) ff:00.1 Host bridge: Intel Corporation Core Processor QuickPath Architecture System Address Decoder (rev 02) ff:02.0 Host bridge: Intel Corporation Core Processor QPI Link 0 (rev 02) ff:02.1 Host bridge: Intel Corporation Core Processor QPI Physical 0 (rev 02) ff:02.2 Host bridge: Intel Corporation Core Processor Reserved (rev 02) ff:02.3 Host bridge: Intel Corporation Core Processor Reserved (rev 02) # sudo lshw -C network *-network description: Wireless interface product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth1 version: 01 serial: 70:f1:a1:49:b6:ab width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.1.7 latency=0 multicast=yes wireless=IEEE 802.11 resources: irq:17 memory:f0500000-f0503fff *-network description: Ethernet interface product: AR8152 v1.1 Fast Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c1 serial: b8:ac:6f:6b:f7:4a capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A latency=0 link=no multicast=yes port=twisted pair resources: irq:44 memory:f0400000-f043ffff ioport:2000(size=128) # lsmod | grep wl wl 2568210 0 lib80211 14381 2 lib80211_crypt_tkip,wl # sudo iwlist eth1 scanning eth1 Scan completed : Cell 01 - Address: 30:46:9A:85:DA:9A ESSID:"BH DASHIR 2" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:4/5 Signal level:-60 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B000103104700109AFE7D908F8E2D381860668BA2E8D8771021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 02 - Address: C0:3F:0E:EB:45:14 ESSID:"BH DASHIR 3" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:2/5 Signal level:-71 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B00010310470010F3C9BBE499D140540F530E7EBEDE2F671021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 03 - Address: A0:21:B7:A8:2F:C0 ESSID:"BH DASHIR 4" Mode:Managed Frequency:2.422 GHz (Channel 3) Quality:1/5 Signal level:-86 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD8B0050F204104A0001101044000102103B0001031047001000000000000010000000A021B7A82FC01021000D4E6574676561722C20496E632E10230009574E523130303076321024000456324831104200046E6F6E651054000800060050F20400011011001B574E5231303030763228576972656C6573732041502D322E344729100800020086103C000103 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s

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  • Computer Networks UNISA - Chap 12 &ndash; Networking Security

    - by MarkPearl
    After reading this section you should be able to Identify security risks in LANs and WANs and design security policies that minimize risks Explain how physical security contributes to network security Discuss hardware and design based security techniques Understand methods of encryption such as SSL and IPSec, that can secure data in storage and in transit Describe how popular authentication protocols such as RADIUS< TACACS,Kerberos, PAP, CHAP, and MS-CHAP function Use network operating system techniques to provide basic security Understand wireless security protocols such as WEP, WPA and 802.11i Security Audits Before spending time and money on network security, examine your networks security risks – rate and prioritize risks. Different organizations have different levels of network security requirements. Security Risks Not all security breaches result from a manipulation of network technology – there are human factors that can play a role as well. The following categories are areas of considerations… Risks associated with People Risks associated with Transmission and Hardware Risks associated with Protocols and Software Risks associated with Internet Access An effective security policy A security policy identifies your security goals, risks, levels of authority, designated security coordinator and team members, responsibilities for each team member, and responsibilities for each employee. In addition it specifies how to address security breaches. It should not state exactly which hardware, software, architecture, or protocols will be used to ensure security, nor how hardware or software will be installed and configured. A security policy must address an organizations specific risks. to understand your risks, you should conduct a security audit that identifies vulnerabilities and rates both the severity of each threat and its likelihood of occurring. Security Policy Content Security policy content should… Policies for each category of security Explain to users what they can and cannot do and how these measures protect the networks security Should define what confidential means to the organization Response Policy A security policy should provide for a planned response in the event of a security breach. The response policy should identify the members of a response team, all of whom should clearly understand the the security policy, risks, and measures in place. Some of the roles concerned could include… Dispatcher – the person on call who first notices the breach Manager – the person who coordinates the resources necessary to solve the problem Technical Support Specialist – the person who focuses on solving the problem Public relations specialist – the person who acts as the official spokesperson for the organization Physical Security An important element in network security is restricting physical access to its components. There are various techniques for this including locking doors, security people at access points etc. You should identify the following… Which rooms contain critical systems or data and must be secured Through what means might intruders gain access to these rooms How and to what extent are authorized personnel granted access to these rooms Are authentication methods such as ID cards easy to forge etc. Security in Network Design The optimal way to prevent external security breaches from affecting you LAN is not to connect your LAN to the outside world at all. The next best protection is to restrict access at every point where your LAN connects to the rest of the world. Router Access List – can be used to filter or decline access to a portion of a network for certain devices. Intrusion Detection and Prevention While denying someone access to a section of the network is good, it is better to be able to detect when an attempt has been made and notify security personnel. This can be done using IDS (intrusion detection system) software. One drawback of IDS software is it can detect false positives – i.e. an authorized person who has forgotten his password attempts to logon. Firewalls A firewall is a specialized device, or a computer installed with specialized software, that selectively filters or blocks traffic between networks. A firewall typically involves a combination of hardware and software and may reside between two interconnected private networks. The simplest form of a firewall is a packet filtering firewall, which is a router that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination or not. Firewalls can block traffic in and out of a LAN. NOS (Network Operating System) Security Regardless of the operating system, generally every network administrator can implement basic security by restricting what users are authorized to do on a network. Some of the restrictions include things related to Logons – place, time of day, total time logged in, etc Passwords – length, characters used, etc Encryption Encryption is the use of an algorithm to scramble data into a format that can be read only by reversing the algorithm. The purpose of encryption is to keep information private. Many forms of encryption exist and new ways of cracking encryption are continually being invented. The following are some categories of encryption… Key Encryption PGP (Pretty Good Privacy) SSL (Secure Sockets Layer) SSH (Secure Shell) SCP (Secure CoPy) SFTP (Secure File Transfer Protocol) IPSec (Internet Protocol Security) For a detailed explanation on each section refer to pages 596 to 604 of textbook Authentication Protocols Authentication protocols are the rules that computers follow to accomplish authentication. Several types exist and the following are some of the common authentication protocols… RADIUS and TACACS PAP (Password Authentication Protocol) CHAP and MS-CHAP EAP (Extensible Authentication Protocol) 802.1x (EAPoL) Kerberos Wireless Network Security Wireless transmissions are particularly susceptible to eavesdropping. The following are two wireless network security protocols WEP WPA

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