Displaying large amount of data [closed] - flutter

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I am working on a mobile application using Bluetooth sensor. My goal is to visualize Bluetooth data on graph. I have 3 different pages on my mobile application:
First page having 3 channels (you can imagine it as as 1 graph and 3 signals, thus 3 curves)
Second page having 8 channels
Third page having 3 channels
The moment I have many channels (like at the second page, 8 channels) the display is slowing down. It is so slow that I cannot even switch between pages. Like if I am clicking but nothing is happening, totally freezed.
I am guessing it is because of the display library that I am using. For those who already have experienced the same issue, any suggestions about real-time charts in Flutter? I have already tested Syncfusion and it is indeed freezing.
Thank you very much.

We tried to replicate the reported scenario by creating the chart based on the shared information i.e., in first page and third page, we have a chart with 3 series, in the second page we have a chart with 8 series. And updated the charts for every 300ms, and we ran the application more than an hour, unfortunately the app didn’t get freeze. We have tried by adding the data to the chart and not removed any data in the above case.
For better performance we suggest using the fast line series and for updating the data source use the updateDataSource and not use set state. The set state will render the re-render the chart, the updateDataSource method will skip old data points processing, unnecessary bounds calculation, etc. For more information on these, find the user guide below.
https://help.syncfusion.com/flutter/cartesian-charts/chart-types/fast-line-chart https://help.syncfusion.com/flutter/cartesian-charts/methods#updatedatasource
We have also attached the sample below which we have used for testing,
Sample link https://www.syncfusion.com/downloads/support/directtrac/general/ze/stackoverflow1887344518.zip
Also, if you are using large data set, we suggest using the on-demand loading feature. For more information this, find the user guide and sample below. If this suits to your requirement, you can make use of this.
UG: https://help.syncfusion.com/flutter/cartesian-charts/on-demand-loading
Demo: https://flutter.syncfusion.com/#/cartesian-charts/infinite-scrolling

Answering my own question because having discovered many libraries, I kind of found the answer: I have tested Flutter Charts library. It works perfectly fine and looks good. Even though I am displaying +3 channel per page, it is not lagging and I can easily switch between pages.

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Best approach to build a dashboard [closed]

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Looking for some advice... just finished a ETL pipeline where all data ends up in Amazon Athena. The data is produced via the click stream of high volume mobile apps (so essentially it’s lots and lots of raw events). I want to build a number of dashboards for the business that show different metrics/KPIs depending on the requirements. However, since we’re talking about huge volumes of data I’m not sure the best way to do this? Here’s an example:
I want a dashboard that shows all the MAUs (monthly active users), along with certain pages that perform particularly well and the most popular navigation routes through the app. My thinking is that I’d want a custom query per graph I.e. one query that is counting the distinct IDs each day (and then refreshing every 24hr)... another query for a graph that produces a breakdown of counts per page and truncates... etc
The main reason for thinking this is otherwise I’d be pulling in huge amounts of raw data just to calculate a simple metric like MAUs (not even sure extract would work - certainly wouldn’t be efficient).
Is this completely the wrong approach? Any suggestions/feedback?
Thanks in advance!
It sounds like you have multiple unrelated SQL queries that you want to run once per day, and update in Tableau once per day.
There's always a pull-push between the processing at the source and in the visualization engine.
Set up a Tableau server extract for each Athena SQL query. Build your dashboards, and schedule your extracts to refresh daily. Like an OLAP cube, this will process all the aggregates your dashboards need with the refresh, for better dashboard performance.
Alternatively, if you feel you don't need all the detail in Tableau, then build your aggregates in SQL, so that your Tableau data sources are smaller.

Image recognition services [closed]

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I'm now current making a mobile application. I want to find a service which I'll upload image of my defined objects : Airplane, computer, ... and when users use the app, they take a picture of the object I already defined in service, the service will tell him/her about the object information, such as: Akai's computer, Akai's laptop, ...
I wonder if there is any image recognition which provides database for inputting images as sample data with information to help me to achieve or not.
Thank you,
There is an important tradeoff here at play. There are two scenarios:
You have relatively few categories (objects for which the user can take an image) and multiple example images for each category. You have plenty of options from the realm of machine learning (neural network frameworks like caffe or Tensorflow). But if you want things to work with relatively small number of examples (you should still have at least tens per category), the easiest way is to use an external API like vize.it where you can set up the categories via a web interface and have the image recognizer hosted externally and accessed via a REST API.
You have many categories and just one or a few examples for each category. I'm personally not aware of any pre-made solutions to such a problem. My approach would be to use a pre-trained convolutional neural network to process the images, using the hidden representation near the top of such network (very much like what is used e.g. on the image side of automated image captioning - example code), and train a classifier that takes a pair of images processed this way and outputs a [0,1] scalar that represents how close the images are. I have experimented with that approach for comparing sentences and that works pretty well, but I expect you will need a big dataset.
Disclaimer: I'm a co-author of vize.it.
when users use the app, they take a picture of the object I already defined in service, the service will tell him/her about the object information, such as: Akai's computer, Akai's laptop, ...
Since your user is trying to identify an instance of an object, and retreive metadata about it, the Watson Visual Recognition service's similarity search feature may be a good fit. It is a beta service, which is free for the time being.
You can add photos with associated metadata (like strings "Akai's computer") into a collection, which indexes the images by their visual appearance. You can then query the collection with the "find_similar" method to retrieve the image ids and metadata from the most visually similar images.
Here is a demo: https://similarity-search-demo.mybluemix.net/ That page also includes a link to the API reference. Watson VR also includes custom classifier training, which you might find interesting.

wireit: visualizing a directed graph with nodes that can contain nested graphs [closed]

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Problem:
There appear to be many tools for visualizing graph structures, but none of the ones I've seen so far seem to have the feature of "nesting". The WireIt library (apparently inspired by Yahoo Pipes) looks very promising, but it seems to lack this concept of nesting.
To explain what I am thinking of, consider a Company Org Chart where each "box" in the Org Chart has a button with three dots [...]
When you click on the button, the chart "drills down" into the sub-organizations within the node you just clicked on, you can use the backspace key (or some other convention) to jump back up to the originating node.
Question:
Does anyone know of a GUI toolkit (prefer web-compatible) that includes this concept of nesting? The WireIt library looks promising, but if there are any others out there you are aware of, feel free to include that also.
TIA for any info.
Flare should be able to handle nested nodes. Look at Layouts -> Circle Pack in the demo. I believe Protovis can also handle nested nodes, though I don't see a demo that shows it off.
Two desktop tools I know of support the kind of nesting you're referring to: NodeXL and Cytoscape. In NodeXL, a network visualization template for Excell 2007--2013, you can define a group manually or using a clustering algorithm, then collapse it into a single node. You can then expand individual groups on demand. Cytoscape has a similar feature, though I'm unfamiliar with the terminology it uses. In the latest version you can even show an image on the group node that shows the underlying subgraph.
Another option is to just separate the groups visually in the drawing. NodeXL includes a new Group-in-a-Box layout that separates groups into their own region of the screen, whether the groups are components, clusters, or manually created. Below are some examples and a reference for the associated paper.
Rodrigues, E. M.; Milic-Frayling, N.; Smith, M.; Shneiderman, B. & Hansen, D. Group-in-a-Box layout for multi-faceted analysis of communities SocialCom '11: Proc. 2011 IEEE 3rd International Conference on Social Computing, 2011, 354-361. DOI:10.1109/PASSAT/SocialCom.2011.139
Disclaimer: I am an advisor and developer on the NodeXL project.
The Graphviz library has the ability to do nested clusters. See this example: http://www.graphviz.org/content/fdpclust
Graphviz doesn't provide the interactive features directly, but provides many tools (like the ability to export SVG or image maps with attached urls and JavaScript events) that you would need to build an interactive app. Also check out some of the items on the "Resources" tab, some of the project like jQuery.Graphviz may provide some of the interactivity you are looking for.

Search engine optimization - Developer guidance? [closed]

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I've just picked up a contract to sort out a vipers-nest of e-commerce websites that a previous 'developer' left for one of my clients. There's about a couple of dozen of them using a custom shopping cart and CMS system that's too embedded to dump and works well enough, but desperately needs cleaning up, re-factoring, and bug fixing, so a reasonably substantial recoding job.
As part of this my client is desperate to ensure the best search engine placement he can get. Like many developers I've a nodding acquaintance with the idea, but no real knowledge, and it seems that it would be helpful to get up to speed on this so I can build appropriately into the code.
So can people advise on useful quality resources - books, websites, blogs etc? I do not wish to obsess over every last detail on this (he can use a specialist if he decides to pull every last ounce out - although I've always regarded such as little better than snake-oil peddlers), but I would like to build code and reconfigure templates in a manner that helps rather than hinders placement.
Look at Wikipedia with styles off. See how they order their content? See how they use correct tags to label the content? These are the keys to long term success.
The most important SEO advice is to create a semantic, logical site. The content comes first and is ordered by importance. Use the correct tags, don't do tables. Then apply styles. Then apply script to make it fancy. (Like Tomas said)
Know the difference between what is content (pictures of your products) and not (your logo tiled on the background). Basically do your best to present good content in a good way. You can't game the system for long term gains.
This will give you long term placement. Most SEO companies just do tricks or links farms or worry about keywords and meta tags, so they are temporary at best. I think it is good to assume that Google works just as hard to drop that crap from it's index as the SEO marketers do to include it.
According to Google's patent
Age of domain.
Important sites that link to you.
Content. Make it real and accurate.
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=20050071741&OS=20050071741&RS=20050071741
A main concern when thinking SEO should always be usability. Make sure the mark-up is semantic, make sure the site works without javascript, css and images - in other words, make sure that 'low-level browsers' are able to read the contents of your page. Think of optimizing the site for a screen reader for the blind and visually impaired, and you will automatically cover the search engines, because that is exactly what they are - blind browsers.
A standard no-no is a table layout, mainly because it does not order the site content by relevance. To a human being reading your site, it is no problem looking two inches down instead of at the very top of your page, but the screenreader reads the code, not the visual view.
Thus, you should make sure that you have the important things - a high-level heading (preferrably <h1> or <h2>), the main menu (in a <ul> list) and the content in divs at the top of the source, and less important content (the logo, banners, quickmenus etc that aren't really crucially needed to be accessible) further down. You are always able to re-order where the stuff is actually shown in your css.
New tag to use called CANONICAL can now also be used, from Google, click HERE

Best examples of CRUD Web Form Design [closed]

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I am looking to revamp our CRUD web forms and would appreciate any examples of good UI design.
We have lots of database tables that have minimal editing needs by the user - Country Codes, Tax codes, Product prices, and so on - and these all currently use a simple format for CRUD, but it was designed by developers and looks very bland, and quite possibly could have far better usability, and certainly a better design.
Our process is:
Find screen - which also has an ADD NEW button. Enter values for any parameters relevant to search for and press FIND button. Matching records displayed in a grid with an EDIT link. The corresponding Edit form allows CLONE, DELETE and SAVE.
Where appropriate an Edit form may display Child Records.
For very complex records / relationships the Edit form is replaced by a Record Card, which displays everything including the kitchen sink! and appropriate records / sub records have EDIT links.
Its functional, but uninspiring.
On an 80:20 basis the code is all mechanically generated, so re-generating it for a new metaphor shouldn't be too hard.
I like a lot of the UI in the Magento eCommerce Admin pages, but I would be interested in any other examples you can recommend
Here are some examples of UI patterns:
Input Controls
Stacked Tabs
Inline Input Adder
One Page Wizards
Overlay
Generally each section will explain the pattern, how and why to use, and gives a handful of graphics as real world examples.
As an additional resource, you can also visit ThemeForest's admin template site and browse through their many products and get pictures and live tours of very well designed and styled admin pages. I personally have used a few of these templates for data heavy sites.
Hope these help you out some.
7/25/18 Update: While it is hard to keep links from nine years ago working, it seem that the website which hosted the UI examples is now gone. Read Farewell from Patternry for further information.
Links worth a look:
http://www.smashingmagazine.com/2008/04/17/web-form-design-modern-solutions-and-creative-ideas/
http://somerandomdude.com/articles/design/form-design/
The Dynamic Data Web Site that you can create using .Net 3.5 is pretty handy. Good clean dynamic CRUD ability and yet very customizable. Routing makes it possible to default to generated pages when needed and custom pages if you choose to create them.
Dynamic Data Web Site
These guys have really nice examples-
http://wufoo.com/gallery/
To me, the Django admin interface is a good example of a CRUD interface.
I've just stumbled onto this one
there you will find a couple of REALLY GREAT templates!!!
http://www.webappers.com/2009/09/18/20-professional-web-admin-templates-on-themeforest/