I want to set up a paradigm in PsychoPy. Pictures will be presented one after an other for 4s each.
There are 2 groups of pictures. All should be presented in a "pseudo" random order. How can I check that there are not more than 3 pictures of the same group in a row?
PsychoPy's Builder interface isn't well suited to implementing randomisation constraints: there are just too many possible things a user might want to do, so it is difficult to create a GUI to account for the possible approaches. The usual advice here is that you would need to use the Coder. Writing your own code allows you to implement any arbitrary randomisation scheme.
If that doesn't seem practical, you could hand-craft a number of conditions files that do what you want. e.g. in Excel, randomise a list of conditions. Check for runs > 3 and shift rows around to fix that. Make a set of such files (say, 5) and randomise each subject to use one of them as the conditions file for that particular session.
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What is the best practice for having many different menus/screens/forms in a visual basic program? Would it be to just make a new form for each menu or screen that I want? Or are there other better options?
I am not trying to make this overly complicated, I have a group project to work on and we all have different skill levels. That said it has peaked my curiosity so I figured it wouldn't hurt to ask before I got started.
I can see this question being closed pretty quickly as being too open ended so allow me to get in my key gripe on this before that happens... no .Visible property for TabControl pages? Seriously, Microsoft??
Which brings me to the key point. If the forms are in some way related but not necessarily identical I prefer to use a single form with different tabs, despite that glaring shortcoming in the control. (Which you don't have to look far to find workarounds for on SO, but a workaround is still a workaround.) Dynamically manipulating controls at run time is another side of this coin, though one that I tend to use more rarely... but that's just a personal thing.
In a recent application, for instance, I had lists of several types of objects. They were related, but performed quite different functions and the user wouldn't really need to look at more than one list at once. As a result I used one form with a tab for each object list to keep the users' display less cluttered.
Similarly when doing a GL app recently I had the journal header and journal line entries (which go to different tables in the back-end database) in separate parts of the one form. On the other hand asset creation was sufficiently different that I created a different form, despite the creation process sharing some of the underlying data. (That is, journal line data.)
I don't believe in the concept of "best practice" because what's a good practice in one situation may be a very bad one in another. However the "rules of thumb" that I use are:
- Keep the number of forms to a minimum to keep overhead low and reduce maintenance BUT
- If there is no logical "tie" between two functions, don't be afraid to make a new form because trying to maintain one form which performs 7 different roles is a guaranteed path to madness and frustration, especially if you break something inadvertently.
Yes, the two rules conflict, but in a way I see this aspect of design as being akin to database normalisation; there's a sweet spot between over-normalising (a separate form for each and every display) and under-normalising (trying to shoe-horn too many unrelated functions into one form). At the very least the rules always give me pause to think "do I need this form, or does it relate to something that I've already done?"
And the third rule of thumb is, obviously... always look at it from the point of view of your user. Are they going to feel like you're bouncing them around too much? Do all of the forms share a look and feel and, more importantly, control layout so that they always know where to find something?
All of these things will vary from app to app, and there's never one size that will fit all IMHO.
In my case, when I am dealing with multiple forms, I use MDI Parent Form to avoid multiple items in the windows task bar.
Another unusual solution is to set each forms ShowInTaskbar property to false.
I have a db model like this:
tb_Computer (N - N) tb_Computer_Peripheral (N - 1) tb_Peripheral
Each computer has N peripherals. But each peripheral is different in nature, and will have different fields. A keyboard will have model, language, etc, and a network card has specification about speed and such.
But I don't think it's viable to create as many tables as there are peripherals. Because one day someone will come up with a very specific peripheral and I don't want him to be unable to add it just because it is not a keyboard neither a network card.
Is it a bad practice to create a field data inside tb_Peripheral which contains JSON data about a specific peripheral?
I could even create a tb_PeripheralType with specific information about which data a specific type of peripheral has.
I read about this in many places and found everywhere that this is a bad practice, but I can't think of any other way to implement this the way I want, completely dynamic.
What is the best way to achieve what I want? Is the current model wrong? What would you do ?
It's not a question of "good practices" or "bad practices". Making things completely dynamic has an upside and a downside. You have outlined the upside fairly well.
The downside of a completely dynamic design is that the process of turning the data into useful information is not nearly as routine as it is with a database that pins down the semantics of the data within the scope of the design.
Can you build a report and a report generating process that will adapt itself to the new structure of the data when you begin to add data about a new kind of peripheral? If you end up stuck with doing maintenance on the application when requirements change, what have you gained by making the database design completely dynamic?
PS: If the changes to the database design consist only of adding new tables, the "ripple effect" on your existing applications will be negligible.
I can think of four options.
The first is to create a table peripherals that would have all the information you could want about peripherals. This would have NULLs in the columns where the field is not appropriate to the type. When a new peripheral is added, you would have to add the descriptive columns.
The second is to create a separate table for each peripheral.
The third is to encode the information in something like JSON.
The fourth is to store the data as pairs. So each peripheral would have many different rows.
There are also hybrids for these approaches. For instance, you could store common fields in a single table (ala (1)) and then have key value pairs for other values.
The question is how this information is going to be used. I do most of my work directly in SQL, so the worst option for me is (3). I don't want to parse strange information formats to get something potentially useful to a SQL query.
Option (4) is the most flexible, but it also requires more work to get a complete picture of all the possible attributes.
If I were starting from scratch, and I had a pretty good idea of what fields I wanted, then I would start with (1), a single table for peripherals. If I had requirements where peripherals and attributes would be changing fairly regularly, then I would seriously consider (4). If the tables are only being used by applications, then I might consider (3), but I would probably reject it anyway.
Only one question to answer when you do this sort of design. JSON, a serialised object, xml, or heaven forbid a csv, doesn't really matter.
Do you want to consume them outside of the API that knows the structure?
If you want to say use sql to get all peripherals of type keyboard with a number of keys property >= 102 say.
If you do, it gets messy, much messier than extra tables.
No different to say having a table of pdfs or docs and trying to find all the ones which have more than 10 pages.
Gets even funnier if you want to version the content as your application evolves.
Have a look at a Nosql back end, it's designed for stuff like this, a relational database is not.
Is there a quick and easy way to make a VB.NET user interface for managing the data in a normalized DataSet?
I know that is a very subjective question, so let me explain. For a brief period early in my career, I used to create user interfaces in Microsoft Access. I developed a simple, but very effective approach to user interface design. Here are some details of that approach:
Create one form per table. Put on
each form all controls necessary to
completely manage one row in the
table.
Use combo boxes for
foreign-key columns.
Give the user a
standard way to add rows and delete
rows.
Use Apply and Undo buttons.
Let
the user navigate from one row to
another with a list box.
Provide a
search box and filter options for
more efficient navigation.
Let the
user double-click on controls
representing foreign-key columns to
quickly navigate from one form to
another.
Make the state of each form
persistent (so the user always
returns to the last navigation point)
etc.
Simple, right? I found that Access encouraged this approach. It has many built-in features that make this kind of UI easy. For instance, creating a combo box to represent a foreign key relationship takes about 10 seconds.
Well, I haven't worked in Access for a while. A couple of years ago, however, I was hired to write an application in VB.NET on the NET 2.0 framework. To get a data management user interface up and running quickly, I used my Access experience to write a quick & easy prototype in Access -- that took me about one week. Then I hired a programmer to implement that same UI in VB.NET. What a nightmare! We've been working on that implementation for a year, and I'm still very unsatisfied with the results. Some of the problems we are having:
Apply and Undo buttons don't work quite right. We can't find an event that tells us when the form is "dirty" (thus making Apply and Undo relevant).
Navigation from row to row and from form to form requires surprisingly complicated code. I get the impression that we are fighting against NET's binding features, not working with them the way they were intended to be used.
The NET controls seem buggy. For instance, when the user types a value into a combo box (as opposed to choosing it from the drop down), it doesn't trigger the SelectedValueChanged event.
We seem to be repeating a lot of information. For instance, the DataSet knows there is a relationship between the columns in two tables, but we must nevertheless effectively repeat the details of that relationship when we program the combo boxes, binding, navigtation features, etc.
We still don't have good solutions for the filter and search features. There are lots of little details to work out. (For instance, what if you choose a filter that doesn't include the currently displayed row?)
We are writing many helper functions and classes to simplify the work, and I can't figure out why that effort hasn't already been done by others -- I'm certain we are reinventing the wheel.
etc.
By themselves, none of the above are a big deal -- there are effective solutions to each one. Taken together, however, these problems are making my UI development go much slower than expected.
In an ideal world, I should be able to create a small amount of code relevant to my specific data model (for instance, one user control per table establishing the layout and logic relevant to the rows in that table) then integrate that code into a template which interprets the data model and handles everything else -- navigation, adding and deleting, apply and undo, search and filter, etc.
Thus, my question: Is there anything out there which makes this type of UI development easier?
I've searched the web for various combinations of "generic forms", "UI templates", "data managment forms", etc., but I haven't found anything on topic. Perhaps I just don't know the buzzwords. Is there a specific name for this type of UI development task?
Create UCs for each table. Drop a grid control onto the UC and bind it to the tables dataset using VS's wizard. Select the options that allow for insert, update, delete. Each row on the grid will have those buttons/actions automatically added for you.
I've researched this issue and have not found anything to meet my needs. I am worried that perhaps I'm using the wrong terms.
I would like to build a website interface that allows users to select different variables and then have those variables dynamical or automatically graphed or charted. I need it to be able to handle 100+ variables (there could be limits to how many were charted at one time) and display the data on a bar graph, pie chart, or line graph based on the users preference.
What would I need to make this happen?
Sounds like you need to use either Flash and ActionScript or JavaScript and HTML5.
I've been looking to do something like this too actually.
Need a facility for parsing the data, and then working out scales/ratios and to represent the data in a coherent way, with labels. Then you need to scale the shapes your using according to the scale that the data is covering, and for the sizes to naturally be proportional.
Maybe this is a shot in the dark here but I'm trying to find out if anyone has thoughts on this problem we have been presented with.
The situation is that we have a database that contains all kinds of data about a large list of projects. There are dozens of tables that all provide supporting info about a project, both in 1 to 1 manner, where some specific type of info about projects (say ProjectInfoTypeA) might be stored in a table called ProjectInfoTypeA, and we'd do a inner join between that and the projects table, as well as 1 to many, like maybe ProjectScopeKeywords, where a project can be assigned N attributes or in this case "keywords" for a number of different attribute/lookup tables.
In the end we need to have the user in our web app build up things like:
Show me all projects completed in the last 5 years that took at least 4 years to do, cost at least $1MM, and have all 3 of these keywords ( x,y,z ) associated with it.
We also want users to be able to save their queries so they, and other users, can select them from a list of saved queries.
Once we get the list of projects from their filter, we need to then work with it in all different ways: but not as a report. If this were a report I'd just give them some report builder of some kind, but we need to work with their filtered list in the web app.
Currently we are thinking of 2 different ideas:
1) being that we just try to write our own UI for building up the query, and then create some giant SQL statement.
2) we store the data about each of their filters in the database, and then when they slick "Search" we would essentially prune down the list of projects by iteratively stripping off the projects that didn't match each query, based on the data they stored in the database.
I'm guessing no one out there has had to deal with something like this, but if any of you had, I'd be interested to hear any suggestions/patterns that would be worth looking into.
I would recommend choosing option 1. I have used a query-builder approach on a number of projects, with varying degrees of sophistication depending on the complexity of the requirements.
If you are in a position to use a ready-made solution, you can find several on the web: http://www.google.com/search?q=sql+query+builder
For a custom built solution, at a minimum, you would probably want to provide flattened views for the user to query from; this will simplify the designer complexity, reduce the learning curve for the user, and provide some abstraction against future schema changes.
After defining your base data sources, you need to provide means by which the user can select specific columns, define filter criteria, specify value aggregation, and define sub-queries (based on your example query requirement). The column selection and filter definition should not be too difficult, but the value aggregation and sub-query creation would be non-trivial to define. You should be able to use the ready-made solutions as examples of how to present this functionality to the user.