Rockit software roc

University of Chicago Medical Center. J ohn A. Swets, Tulips to Thresholds. Our recent progress has included the addition of many non-parametric methods for analysis of ROC data [10] and a review of the medical-imaging literature to determine the spectrum of ROC methods used in published observer performance studies [11]. Generalization of conventional ROC analysis to evaluate diagnostic tasks that involve more than two decision alternatives is under investigation [12,13], and we will release software capable of analyzing such data as soon as possible.

Radiographic applications of signal detection theory. Radiology , Metz CE. Basic principles of ROC analysis. Seminars in Nuclear Medicine 8: , ROC methodology in radiologic imaging.

Investigative Radiology , Assessment of medial imaging systems and computer aids: a tutorial review. Academic Radiology , The program itself was written and tested by Lorenzo L. Pesce and John Papaioannou. The code is an almost completely rewritten version of parts originally written by Benjamin A.

Metz, P. Berbaum, P. Make sure to take note of these for replication, publication and bug-reporting purposes. Note1 : Throughout program execution, only the tabs or options in full color and those with black text are available, whereas the other ones cannot be selected.

Note that the available options can change during different phases of execution to serve as a guide as to what options are appropriate during the current phase of execution. The available options can change also in different versions of the program as more options become available. The following steps describe ROC-kit's features. Various alternatives are possible, and not all of their combinations are described explicitly here.

Note: Older implementations of some of ROC-kit's algorithms allowed manual input of data. This is no longer possible, so an input file must be created first. The manual-input option was dropped because it was and highly vulnerable to typographical errors and rarely used. After a file has been selected, a pop up window will ask what kind of input file it is. Figure 3. A description of the different input file types is provided later in this guide.

If the format of the input file contains one or more errors, a descriptive error message is generated to help determine is the nature of the problem, as in the example shown in Figure 4. Figure 4. A more complete description is provided later in this guide. Figure 5. Note: The height of the whiskers in each of ROC-kit's "box-and-whiskers" plots indicates the range of test-result values from actually-negative and actually-positive cases in the input data file, whereas the height of each box indicates the 25 th -through 75 th percentile of those input values.

Moreover, each box's width shows the relative numbers of actually-positive and actually-negative cases in the sample e. Figure 6. The main window is divided in two sections: the top one contains a quantitative description of the data, whereas the bottom one displays data as a box-plot.

The checkboxes in the latter allow the user to select subsets of the data for specific types of analysis. Figure 8. Note: the button at the end of the file name can be used to change the input file. Using this button will bring up the pop up window described in Figure 2. Note: the button at the bottom of the upper internal frame of the window can be used to reselect the entire dataset as described in the file. For details about how to select subsets of the data, see following section.

Not all versions of the software are capable of analyzing complete datasets e. Alternatively, one may wish to select only a part of the data for analysis e. Figure 9. The ROCKIT file is displayed with case-pairing matrices because a different number of cases can be available to different modalities. As already stated each modality has been applies to the same actually-positive and actually negative cases paired design and all readers read all cases for all modalities fully-paired design.

Figure Note how the top internal frame shows only the selected data. ROC-kit will then automatically proceed through a sequence steps depending upon what kind of data was selected i. The following screen will appear Figure 12, differences among different dataset types might exist, as it will be explained in the following. Grayed options are not available for use, either because they been have not implemented in the release being run, because they do not apply to the specific analysis chosen, or because other choices must be made first OS X Note: Some of the options within this window usually will be grayed.

For example:. Clicking on it will yield a new window, shown in Figure This window allows the user to select a method to estimate uncertainties. Note: It is possible to go back to any of the previous windows if any change needs to be done, e. In general, any icon or check button that is active can be used to select new choices or undo previously made ones.

Program window: Uncertainty estimation options. This window is divided in two internal frames, one that allows the user to select an uncertainty estimation method and the other that presents the reader with a summary of the data and options that were selected for this analysis this summary can be cut and pasted for reporting or logging purposes. Four methods are available when a semi-parametric or parametric method is chosen and were briefly described above:.

Three methods are available when a non-parametric method is chosen and also were briefly described in the overview section:. This button can be seen in Figure 13 but is inactive there because no uncertainty estimation method had been selected. The results section begins with an upper internal frame that describes what options are available. Program window, upper internal frame: Results Options.

This example shows the options that would be displayed after a single ROC curve fit was done using a non-parametric approach OS X The display options are described in the following bulleted points.

Default values are simply those that we have used from time to time in the past and should not be considered appropriate for particular research purposes. All values that depend upon a user-selected threshold should be chosen thoughtfully before the analysis is performed. Shown for a single Curve fit done using a non-parametric approach OS X The data internal frame contains several tabs.

We describe the tabs here only for a single modality, because multi-modality tabs are organized equivalently. Here we describe the different input files formats accepted by ROC-kit and then briefly describe how to prepare input files using conventional text editing or spreadsheet programs. Data for ROC analysis usually represent either continuously-distributed numerical values or ordinal-category confidence-rating data.

Continuous data and all numerical category data are entered into the input file as they are according to the instructions of the following sections. Ordinal-category data, if expressed verbally e. Of course care must be taken to give larger values to categories that express higher probability of containing the signal if that ordering is specified in the input file.

Note : the program is very flexible and accepts many different kinds of number formats as input data. The different types of input files that can be employed with the installed version of ROC-kit can be viewed when a file format specifier pops up after an input file has selected. Description of the following input-file types are provided here:.

Note1: the input file extension has no effect on how the program reads the data; instead, each file format is selected by the user via the file format specifier.

Note2: Files must have been saved previously as text files to be readable by of ROC-kit. In the following, numbers represent lines or groups of lines in an input file, whereas bullets indicate descriptions of those input lines.

Note: when using categorical data you need to convert it to this format. For example, if you have the following categorical data:. Numbers represent input lines or groups of input lines, whereas bullets represent the description of those input lines. Many programs can be used to create input files as described above, e. However, it is essential that these programs save the input file in a text-only word processor or formatted-text spreadsheet format. On some systems or when using specific editing software, it may be necessary to try a few different alternative.

Actually-negative cases are those cases that have been verified to be negative with respect to an explicitly-specified disease of interest. This means that the researcher is very confident, or as confident as possible, that these cases in fact do not contain the signal that is being sought e. Verification of actually-negative cases usually is accomplished by using an independent, highly accurate diagnostic tool, often known as the "gold standard.

Actually-positive cases are those cases that have been verified to be positive with respect to an explicitly-specified disease of interest. This means that the researcher is very confident, or as confident as possible, that these cases in fact contain the signal that is being sought e. False Positive Fraction FPF — or equivalently, False Positive Rate FPR — corresponds to the number of actually-negative cases incorrectly diagnosed as positive by the modality under investigation divided by the total number of actually-negative cases — i.

The same applies to all the following definitions. A False Positive FP is an actually-negative case that has been classified incorrectly as positive. Similarly, a False Negative FN is an actually-positive case that has been classified incorrectly as negative.

FPF is equivalent to 1. True positive fraction TPF — or equivalently, True Positive Rate TPR — corresponds to the number of actually-positive cases correctly diagnosed as positive by the modality under investigation divided by the total number of actually-positive cases— i.

A True Positive TP is an actually-positive case that has been classified correctly as positive. Similarly, a True Negative TN is an actually-negative case that has been classified correctly as negative. TPF is equivalent to "Sensitivity".

Estimates of these index values can be computed from empirical ROC data. They can be estimated either as a function of a threshold setting against which the test-result decision variable is compared or as a function of the complementary decision fraction — i. At least in principle, another example of ordinal categories is provided by the BI-RADS reporting scale used in mammography. Data of this kind are often called categorical or discrete because there are many fewer categories than data points and usually the distinction between categories is rather sharp though this does not preclude the existence of borderline cases.

For analysis, the category labels usually are replaced by integers to replicate a rank-ordering of the data, e. Usually there are many more possible values than data points. In general, empirical datasets range from those that represent data in a very few categories only two for an analysis in terms of sensitivity and specificity to those that involve subjective probability scales with perhaps several hundred categories, or to those that use the quasi-continuous scales of clinical laboratory tests or neural-network outputs.

One should note that apart from numerical and statistical issues e. Usually it is called "area under the curve" AUC , because this terminology applies to any ROC curve, defined using any model, whether parametric, semi-parametric or non-parametric. One should note that " A z " technically refers only to areas under ROC curves that arise from the conventional binormal model CvBM ans so should not be used to represent AUC in general.

Often this partial area under the curve is denoted by "pAUC", which applies to any ROC curve, defined using any model, whether parametric, semi-parametric or non-parametric. If the user selects a subset of an MRMC dataset that involves only a single reader and a single modality, then the resulting sequence of actually-negative and actually-positive cases will be referred to hereafter in this guide as a reader-modality dataset.

These are called "Leave-None-Out" estimates, because no cases are left out of the sample. Our Mission Statement: To provide a rewarding experience to any person wanting to further their growth in rocketry, by providing exciting products that teach, as well as showing how fun and safe the hobby can be.

We also provide in-depth information about rockets, so that customers can make informed decisions about rocketry so they save money. Read More Call and talk to a real person! Fax Us: Email Us: Contact Form. What does "Design and Simulation" software like RockSim do? What else does RockSim do for me? What sorts of designs can I make with RockSim? How does RockSim differ from other programs? How easy is it to learn RockSim? What are the educational benefits to using RockSim?

How is RockSim compatible with maunfacturers and other software? Who else uses RockSim? Is RockSim Expensive? So, you're designing a rocket. You have several options for judging stability of a design. RockSim Design Software See below! Here is what our customer's say about RockSim: "I am really impressed with your software program, not only for the ability to design a rocket, but also the information that can be obtained with launching the rocket under various conditions, etc.

RockSim allows you to take your cool rocketry ideas, and flush out the concept to see if they'll be stable when you launch them. This is important, because you want to make sure all your homebrew creations are safe. This process of selecting parts, and arranging them into a rocket to see if it will work is called "designing" a rocket.

I'm sure you'll be interested in a multitude of statistics: How fast it will zoom? How high it will soar? How long it will hang in the air after the recovery device is deployed?

This is accomplished with a rocket "simulation" program. I changed the shape or the number of fins on my rocket? What if I changed the length of the rocket?

I added pods to the rocket? I use a 38mm motor instead of an 29mm? I use a streamer instead of a parachute? The coefficient-of-drag is broken down into various contributors: nose cone and body profile drag, base drag, launch lug drag, and fin drag.

You can use this feature to tweak your rocket for optimum altitude performance. Again, RockSim was the first program that has this feature. Without it, you can't really tell with any certainty how high or how fast the rocket will travel, let alone what the trajectory will look like. That is a very simple question to answer once you have RockSim. Just imagine people coming to you for that answer. With just two clicks of your mouse button, you'll have RockSim running simulations and recommending the right motors for your design.

It is based on a set of 5 safety criteria that we use here at Apogee Components when we recommend rocket engines for the kits we sell.

With it, you can: Print out fin templates. RockSim's fin templates can be highly complex and include the through-the-wall fin tab and curvature matching of the boat tail. If the fin is huge, RockSim tiles the template onto several sheets of paper with corner marks so you can assemble them like a puzzle. These templates can be transferred to wood or fiberglass, and cut out to make actual rocket components. You can also print out transition-section pattern sheets which you can assemble into an actual part in your real rocket.

To use this feature, you simply need to print out the transition template from the print menu. However, there are a few conditions you have to set up prior to printing it out: 1. The transition cannot have shoulder inserts specified. The transition must be set to "hollow. The transition shape must be set to "Conical.

Note: That if any of these conditions are not as specified above, you will get the default "side view" of the transition when you print out the template.

Rocket Tip: Do you need help in assembling your transition? Click here to watch a movie on how to make the perfect transition. Print out nose cone templates that you can use as an aid in turning or carving your own component. Print out 2D blueprint-like drawings of your rocket. These serve as a guide, so that you position the components properly when assembling the rocket. Print out a 3D picture of your rocket, including the paint scheme and your own custom decals.

From this, you'll have a guide for painting and decorating your rocket design. And it is something you can share with your friends to prove you designed the rocket yourself, and it really isn't a kit you've built. Print out a parts list, so you can check them off as you order them from your favorite vendors. Print out exact centering ring templates, that can be transferred to wood sheets, from which you can cut actual rings. Export out a. You can email your completed RockSim design to vendors who can custom make nose cones, centering rings, and fins directly from your design file.

So you can buy many of the custom parts you've made in your design. Also, with the RockSim9 update, the following features were added: External Pods can be added to the outside of the main body Strap-on Booster Pods are ejectable during flight Fins can be attached to other fins Ability to scale your design up or down Scale custom fin shapes up or down New plot graph screen. You can zoom in on any area of the graph for a closer look at the data.

Anti-alias of the 2D image. New 2D top-view to go with the existing side and base view. New stability overlay to see if your asymmetrical designs are stable in all axis.

Incorporated engine search feature to find new motor data files on the web site www. Tell Me More About This Thing Called "Dynamic Stability" For nearly 40 years, modelers have used "static" stability methods to find out if their rockets will travel in safe manner. Is That True? You can view all of them here: Quickly learn the basics of RockSim by watching video instructions These step-by-step videos walk you through creating a designs, running simple simulations, modifying the user settings, creating asymmetrical fins, playing with the competition settings, and viewing the flight profiles.

You have to ask yourself, "Why did these other companies choose RockSim? As you can see, if you don't use RockSim, you will not be compatible with the rest of the rocketry world.

So stop and ask yourself: "What would happen, and how would you feel if you didn't get RockSim today? Here is a very quick review of some of what you get when you invest in RockSim: Tried, Tested and True: People that spend thousands of dollars on big rocketry projects trust the results of RockSim. For them, it is very cheap insurance on making sure their expensive rockets will work correctly. Compatibility: More people use RockSim than all other programs combined.

Nearly all the major rocketry manufacturers use RockSim too. This allows you to swap and download RockSim designs to save you even more time and money.

Educational: With RockSim's advanced 2D flight profile, you'll learn about rocket science faster and with greater clarity than any other method. And it is so fun, you won't even realize the educational value you or your students are absorbing. Useful: The best aspect of RockSim is that it offers something for everyone in your rocket-loving family. From your kids, to yourself -- each of you will gain something new and unique from using RockSim.

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Innovation: If you really want to be on the cutting edge of technology, then RockSim is for you. RockSim continues to pioneer many useful features. Here are just a few: Free-Form Fin shapes, Dynamic Stability analysis, Asymmetric fin configurations, 2D flight profiles that show you the trajectory of your rocket, Drag prediction, Ring-tail fins, Tube fins, and now stability determination of falling booster stages.

Instructional videos: These videos will quickly walk you through the design and simulation of your first rocket. This is especially great for you if you've never used a computer before. Technical Report How to use RockSim to select the best rocket engine for the design you create. RockSim-In-Depth : A series of technical reports and how-to articles covering a variety of different topics, like: Unstable descents Tumble-Recovery design criteria Designing short or stubby rockets Spin stabilization techniques Running quicker simulations in RockSim Learning about Optimum mass A discussion of fin flutter Determining Base Drag Setting up asymmetric fins in RockSim 7.

This is a list, by topic, of all of the great articles the Peak of Flight put out over the years. There is endless amounts of RockSim information found in this newsletter. Talk to a Real Person! How rockets work and what should you fly. I need info on Rocket Motors. Differences in motor types and brands. I want to fly bigger rockets! Setting up to fly rockets on E, F or G motors. I'm looking to get High Power Certified. Find out the process and our recommended kits.

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