HE1 -- Good Feature



Usability Aspect ReportRaman Fedarenka, Christopher Herr, Lyndsi Hughes, Joshua McCauleyIS 2470 – Interactive System Design04 March 2010URL: group reviewed a bitwise operator calculator applet developed by Amruth Kumar of Ramapo College of New Jersey. The applet is designed to facilitate and stimulate the learning of college level students in various areas of computer science. We choose this applet because it was designed to increase learning, and we felt that in order to be completely effective the applet should be designed in the best way possible; furthermore it is quite complex, and made use of many different features.For the bitwise operators applet students are to evaluate a set of bitwise equations and derive a correct solution. The application assumes that one has a basic understanding of how bitwise operators work, making this application not suitable for beginners. However, the user is able to choose the portion of the equation that they would like to solve by simply clicking and dragging the mouse form the beginning to the end of the portion they wish to solve. Upon completion the user is provided a new prompt box in which they are to solve the part they selected. When the user submits the problem for grading they are provided with immediate and direct feedback, which offers to help the student learn from their mistakes.While the applet maximized the use of backend java coding, the GUI left something to be desired. We found twenty-three (23) heuristic characteristics in the applet, twelve (12) problem areas and eleven (11) well-designed features. We noted it was easier to find the flaws because the problems are what make more of an impression on the user when first encountered. No error that we found made the application completely impossible to use, however, there were some features which could be greatly improved upon. Overall the group felt that the applet accomplished its goal in helping the student learn how to properly solved bitwise operator functions.Project Completion ScheduleEach member reviewed the suggested applets (Fedarenka, Herr, Hughes, McCauley)One applet was chosen by the group (Fedarenka, Herr, Hughes, McCauley)Each member completed a series of UAR reports (Fedarenka, Herr, Hughes, McCauley)Individual UARs combined (Hughes, McCauley)Final UAR reviewed and proofed (Fedarenka, Herr, Hughes, McCauley)Outline and cover sheet written (Hughes, McCauley)IDCategoryGood featureProblemHE1: Unintentional exit preventionProvide Good Error Messages, Diagnose and Prevent ErrorsHE2: Use enter key to submit answer in windowProvide ShortcutsHE3: Warning when using invalid operationProvide Good Error MessagesHE4: Evaluation Tree DepthFeedback, Minimize user memory loadHE5: Curly Brace for Evaluation ControlSpeak the User’s LanguageHE6: Color coded braces and responsesFeedbackHE7: Instruction Set HierarchySimple and natural dialog, Minimize Memory Load, Prevent Errors, Be ConsistentHE8: Snapshots in instructions.Speak the User’s LanguageHE9: Very helpful instructions.Be ConsistentHE10: Examples of values of each type.Be Consistent/Speak the User’s LanguageHE11: Very clear explanation of the solution to the problem after submitting the answer.Speak the User’s LanguageHE12: Initial Instruction WindowSimple and Natural Dialog, Speak the User’s Language, Provide Clearly Marked Exits, Provide Adequate FeedbackHE13: Lack of space for explanation and feedback upon problem completionSimple and natural dialogHE14: When time to use the tutorial has run out, the application closesSimple and natural dialog, Provide adequate feedbackHE15: User must recall binary representations of numbersMinimize Memory LoadHE16: Invalid menu entries not grayed outProvide adequate feedbackHE17: Impossible to decipher effect of selecting menu entriesProvide adequate feedbackHE18: Non-applicable options for entry are displayedProvide adequate feedbackHE19: Time VisualizationProvide adequate feedbackHE20: Expression selection error handlingSimple and Natural Dialog, Prevent ErrorsHE21: Applet opens in new windowPrevent ErrorsHE22: Misleading and confusing buttons.Provide clearly marked exits/ Speak the User’s LanguageHE23: Pop-up message box has misleading information.Simple and natural dialogHE1—Good FeatureNameUnintentional exit preventionEvidenceHeuristic: Provide Good Error Messages, Diagnose and Prevent ErrorsWhen the user attempts to close the window before the tutorial time has expired, the following error message appears.124968073025ExplanationWhenever the program is closed before the tutorial session is over, the user is forced to confirm this choice by selecting the appropriate option in the dialog box. BenefitIf a user tries to exit, the system confirms this choice and gives the option to return to the tutorial. This can prevent accidental closings of the program, and is a good error prevention mechanism.Trade-offsIt requires an extra click to actually close the program if the choice was not a mistake.RelationshipsHE3ObserverLyndsi Hughes, Raman FedarenkaHE2—Good FeatureNameUse enter key to submit answer in windowEvidenceHeuristic: Provide shortcutsThis option is available when the user is submitting an answer and the submit answer dialog box is open.ExplanationWhen the user has calculated his answer and is entering it in the submission dialog box, typing the answer and hitting Enter causes the answer to be submitted. BenefitThis is a nice shortcut for experienced users so that they are able to submit an answer at the keyboard without having to switch back to the mouse. .Trade-offs.RelationshipsNoneObserverLyndsi HughesHE3—Good FeatureNameWarning when using invalid operationEvidenceHeuristic: Provide good error messagesWhen the user has submitted an answer for all possible operators and subsequently tries to select an operator again, an error message appears.440055-2390775ExplanationOnce the user has answered the problem, he cannot attempt to select one or more of the operators to submit another answer. This prevents an invalid answer from being submitted and the dialog box that appears adequately explains to the user what has happened.BenefitThis prevents the user from submitting too many answers to the problem.Trade-offsThis prevents the user from making a mistake in calculating the correct answer. While the selection could have been inadvertent, this also prevents the user from learning why they cannot make this selection when they read the feedback on the problem. RelationshipsHE1ObserverLyndsi Hughes, Chris HerrHE4 -- Good FeatureNameEvaluation Tree DepthEvidenceHeuristic: Feedback, Minimize user memory loadThe way the expression tree is drawn allows for instant feedback and allows the user to see the order in which they evaluated the expression of the equation..ExplanationThe user must properly evaluate a given bitwise expression, step by step. The way the expression tree is drawn allows for the user to see the steps they used, which reduces the need of the user to remember the exact process that they used.BenefitThe user can easily identify the process that they used compared to the method that the correct way to evaluate the expression used, upon submit, if they were incorrect.Trade-offsThis feature can cause issues if the users display screen is very small.RelationshipsHE6Submitted ByJoshua McCauleyHE5 -- Good FeatureNameCurly Brace for Evaluation ControlEvidenceHeuristic: Speak the User LanguageThe curly brace allows the user to easily select the parts of the expression they would like to evaluate and the order in which they would like to accomplish the task..ExplanationThe user must properly evaluate a given bitwise expression, step by step. For this purpose using a box to capture the part of the equation you wish to evaluate is ineffective because the remaining part of the un evaluated expression would have to be redrawn on the sub-line. A curly brace drawn below the expression allows for the appropriate capture of all elements of the equation.BenefitThe user is easily able to see which part of the expression they are attempting to evaluate. The brace allows for the easy ‘cascade’ of expressions so evaluated values on a new level can be captured with an expression element and existing value on a parent level.Trade-offsThis feature can cause issues if the user consistently does not start or end the brace in the correct location because a value of the expression may be missed, or an extra evaluation symbol may be captured by the brace, both of which pose problems.RelationshipsHE6,HE20Submitted ByJoshua McCauleyHE6 -- Good FeatureNameColor coded braces and responsesEvidenceHeuristic: FeedbackUpon completion of a task the system assigns a red or green color to the action performed to denote whether the action was correct or incorrect..ExplanationFor an application attempting to help a student learn how to do something, instant and direct feedback is often the best way to accomplish this task. With this feature the user is able to see how they are doing before they submit the response for grading.BenefitThe user receives instant feedback to the action they just completed.Trade-offsThis feature is relatively useless to users who are affected by red/green colorblindness.RelationshipsHE5,HE6,HE20Submitted ByJoshua McCauley, Chris HerrHE7 -- Good FeatureNameInstruction Set HierarchyEvidenceHeuristic: Simple and natural dialog, Minimize Memory Load, Prevent Errors, Be ConsistentThe hierarchy of the instruction tree allows the user to break it down to provide high level instructions, or low level instructions, depending on their familiarity of the system..ExplanationWhen using any application a help file is very important. They attempt to provide the user to any questions that they might have about the functionality of the system, or the process in which things should be done. Having a collapsible type tree will help advanced users see the high level instructions they may need to refer to occasionally; while still providing low level support to novice users. Each instruction tree is consistently colored and formatted. Blue is the top level instruction, green is the intermediate, and yellow is the lowest.BenefitThe ability to reduce the tree allows the user to reduce the instruction set to only those that they want to see, and can minimize distractions from their current task. This can help prevent errors by trying to complete the incorrect task. The consistent coloring can help a user know the level of depth for the step they are working on, and allows them to quickly come back to the same colored step as they work on the problem.Trade-offsThe ability to expand or reduce the instruction set introduces and extra level of complexity that a novice user might find to be confusing. The bright coloring can be slightly distracting to the eye.RelationshipsHE7,HE8Submitted ByJoshua McCauley, Chris Herr, Raman FedarenkaHE8 – Good FeatureNameSnapshots in instructions.EvidenceHeuristic: Speak the user's languageA very easy way to teach is to show an example. By doing this the user can see what to expect as a reaction to his actions.ExplanationInstructions provide snapshots of real operations so it improves the understanding of the actions he has to perform.BenefitImproves usability.Trade-offsIncreases the size of page and the amount of space the user has to scroll through.RelationshipsHE7,HE9Submitted ByRaman FedarenkaHE9 -- Good FeatureNameVery helpful instructions. EvidenceHeuristic: Be consistentUser learns how to use this part of applet and applies the knowledge to similar parts of applet.ExplanationInstructions on right side show user how to solve problem step by step and in very detailed manner.BenefitUser can easily check these instructions without doing any actions every time he has difficulties.Trade-offsCan use this space for some additional view options. For example “answers counter”.RelationshipsHE7,HE8Submitted ByRaman FedarenkaHE10 -- Good FeatureNameExamples of values of each type.EvidenceHeuristic: Be consistent/Speak the User’s LanguageExplain the user all the types of values that he is allowed to provide as answers. These types are applicable to all problems.ExplanationGive examples of values of each type that user must choose to enter.BenefitCan help reduce errors of entering incorrect type value.Trade-offsNone. RelationshipsHE11,HE18Submitted ByRaman FedarenkaHE11 -- Good FeatureNameVery clear explanation of the solution to the problem after submitting the answer.EvidenceHeuristic: Speak the user's languageMake the problem an example an explain it.ExplanationEach solution of problem is explained in details, given examples and the rule used to solve it is explained too. And user is told whether the problem was solved correctly of not.BenefitImproves user understanding and teaching quality.Trade-offsToo detailed information may annoy experienced users.RelationshipsHE10,HE13Submitted ByRaman FedarenkaHE12—ProblemNameInitial Instruction WindowEvidenceHeuristic: Simple and Natural Dialog, Speak the User’s Language, Provide Clearly Marked Exits, Provide Adequate FeedbackWhen the user first loads the applet they are presented with general usage instructions. They specify that the user is to solve a problem, submit the answer, receive feedback and move on. There is also an option to close the instructions within the instructions window and a Done button at the bottom of the window. It is not clear how to exit the screen. Furthermore, one must wonder if this screen is actually needed.430530882651353820-1278255ExplanationThe instruction section of the interface is very short and rather ambiguous. The user knows that he is supposed to be solving a problem, as indicated in the pre-tutorial instructions, but nowhere in the interface is it specified what types of problems the user is to complete. The instructions also express that the user will be receiving feedback, but it is unclear what this means initially. The instructions then indicate that the user will “Start Over” after each problem. The option to close the instructions simply hides the entirety of the instruction text in the same window, as does the option to “Hide Explanation.” The title bar simply reads “Bitwise-Usage Instructions” which is unacceptably vague. The “Done” button allows the user to proceed to the tutorial when he has finished reading the instructions.SeveritySevere: First, the instructions aren’t even shown by default on the welcome page. Second, the instructions do not tell the user how to leave the screen. I was left to click close instruction over and over before I realized there was a ‘Done’ button in the bottom of the window. All the instruction provided in this window could easily be provided in the instruction set for the applet; the user gains little from this instruction manual that will aid in the use of the system.Possible SolutionInclude in the initial instructions what types of problems the user can expect to be presented with. Program the title bar to describe the type of tutorial more accurately and effectively, for example: “C++ Bitwise Operator Lesson.” Remove the Hide Explanation option and the Close Instructions option, as these are redundant and because the Close Instructions option does not actually close the instructions window as the text would indicate. The “Done” button could read “Continue to Tutorial.” and also be placed somewhere less ambiguous, such as immediately following the final instruction. In its current location it blends in with the typical location for a window border or scroll bar. All the individual instructions could be worded better and contain more useful information.Also, an alternative solution is to remove the welcome page completely and if the instructions provided by it are deemed important, they can be incorporated at the beginning of the usage instructions. RelationshipsHE22ObserverLyndsi Hughes, Joshua McCauley, Chris HerrHE13—ProblemNameLack of space for explanation and feedback upon problem completionEvidenceHeuristic: Simple and natural dialogWhen a problem has a long explanation, the feedback section does not offer enough vertical space to view the entire explanation on small screens. Also, the user must scroll right in some cases to see the entirety of the feedback information.2192655-2561590ExplanationThis issue was encountered when some of the more complicated problems completed had long explanations on how to solve them when the system was offering feedback to the user after the solution was submitted. SeverityMild: the problem with the vertical display occurs mainly when the user is using a small monitor. Also, it is not a difficult task for the user to use the scroll bar to finish reading the line of text.Possible SolutionOffer a vertical scrolling option on the feedback portion.RelationshipsHE11,HE7ObserverLyndsi Hughes, Joshua McCauleyHE14—ProblemNameWhen time to use the tutorial has run out, the application closesEvidenceHeuristic: Simple and natural dialog, Provide adequate feedbackUpon use of the interface, the program closed without warning each time the timer had expired.ExplanationAs the user is working through the problems in the tutorial, the program is keeping a running timer. When the timer is up, the user is not permitted to do any further calculations. This is achieved by exiting the application once the user has submitted the final solution after time expires. The user is not shown any results or indication that the program is about to close.SeveritySevere. The user has no warning or indication that the tutorial is over and that the application is about to close. If the user is not paying close attention to the clock, this can be very unexpected.Possible SolutionProvide a dialog indicating that time has expired and the tutorial will now close.RelationshipsNoneObserverLyndsi Hughes, Chris HerrHE15—ProblemNameUser must recall binary representations of numbersEvidenceHeuristic: Minimize user memory loadThis becomes an issue when the user clicks the help button in the answer submission box. The user is guided through choosing the correct binary representation of two integers and calculating the expression using those two integers and the operator in question. These binary representations simply disappear after they are submitted, so if the user needs them later, they must be recalled.ExplanationWhen a user has selected an operator and operands, a dialog appears in which the user can enter the solution to the expression. There is a help button which helps the user convert the operands into binary format and perform the appropriate operation. Once the answer is computed, this binary representation disappears. Also, on some problems with multiple operators, the user must enter the solution to a previous answer in binary format. This representation is not displayed or remembered and the user is forced to recall it or use the help function to compute it again. SeverityMedium: the user is unsure of the number of bits to be considered in the problems and the only way to find out is to click help so the system can walk the user through the process. Possible SolutionAlso, the interface could include a workspace where the user can record partial answers and refer back to this information as he continues to solve the individual problem, eliminating the need to recall the binary representations or to write them down on a separate sheet of paper. RelationshipsNoneObserverLyndsi HughesHE16—ProblemNameInvalid menu entries not grayed outEvidenceHeuristic: Provide appropriate feedbackOnce the user has submitted his answer and feedback is displayed in the feedback window, the Edit menu shows two options for undoing the previous entry. These are invalid at this point because the solution has already been submitted.639445-2203450ExplanationAfter the solution has been submitted, the user cannot undo the last entry of clear the entire answer, yet the Edit menu still shows these as valid operations. Clicking on these has no effect on the system, as there is nothing to clear or undo, but there is no feedback provided to the user as to what happens in response to a click, since these appear to be valid selections.SeverityMild: the user can do no damage to the system, this just adds a bit of confusion.Possible SolutionGray-out the menu options which are not applicable at a given time. RelationshipsHE17ObserverLyndsi HughesHE17—ProblemNameImpossible to decipher effect of selecting menu entriesEvidenceHeuristic: Provide appropriate feedbackWhen the user selects the options menu and attempts to navigate, it is not clear what effects these actions have on the system in all cases, particularly the Reflection option.Also, the Feedback menu under format is ambiguous in the same way. The system offers no feedback as to what selections under this menu accomplish.563245-1310640The View menu does not provide adequate feedback as well. When View->Log is clicked, the Log appears in a separate window. When the window is closed, the Log option under the menu remains selected. 2439670-799465373380-5342255ExplanationThere is minimal explanation as to what the different choices for Reflection accomplish and no documentation available to help the user decide if this is an option he would like to choose or not. No feedback is given by the system reflecting the selection of this option as well, so the user cannot experiment and determine what these choices do.The same is true of the Format->Feedback menu. There is no indication what these selections are for and what they accomplish.SeverityMildPossible SolutionWhen options are selected, a dialog box could appear and describe the action that the user just selected and the effect it will have on using the interface.RelationshipsHE16ObserverLyndsi Hughes, Chris HerrHE18—ProblemNameNon-applicable options for entry are displayedEvidenceHeuristic: Provide appropriate feedbackWhen the submission dialog appears, not all entries described are valid entries.278130158115ExplanationSeveral of these options are not at all applicable to the types of problems being solved in this tutorial, such as Short Circuited steps or Characters. “Error” however is a valid entry for some of these problems. This can be confusing when trying to decide on an entry. SeverityMediumPossible SolutionGray-out or hide entries that are not appropriate at a given time or for a given problem-set.RelationshipsHE10ObserverLyndsi HughesHE19—ProblemNameTime VisualizationEvidenceHeuristic: Provide appropriate feedbackThe Slider in the timer section is visible whenever the timer is visible, but it’s function is completely ambiguous.28765530480ExplanationThe Slider Bar in the timer area has no apparent functionality of a slider at first glance. When slid all the way to the left, the timer shows a visible countdown second by second. When the slider is positioned further to the right, the countdown increments in larger numbers of seconds. However there is no feedback as to exactly how many seconds the counter is incrementing.SeverityMild: this does not affect system use, but is ambiguous for a user who has a certain expectation of what a slider should do. A user would typically want a steady countdown second by second, so why there is an option for anything else is unclear. Possible SolutionRemove the slider completely and just allow the countdown to decrease on a second by second basis. If the countdown decreases performance of the problet, then allow for a radio button to turn the countdown on or off completely.RelationshipsNoneObserverLyndsi Hughes, Chris Herr, Raman FedarenkaHE20—ProblemNameExpression selection error handlingEvidenceHeuristic: Simple and Natural Dialog, Prevent ErrorsWhen the user wishes to select an operand to calculate, he must click and drag the mouse to select the operator and operands in the desired expression. If the user does not successfully select an operator and all its operands the user is still allowed to enter an answer.1278255914401487170129540ExplanationThe user must successfully drag the brace around the correct operands surrounding the operator to make a valid selection. This is confusing to first-time users. Also, if the correct selection is not made, the dialog box to enter a solution appears and the user has to back out of that by canceling, then attempt to make the correct selection.SeverityMedium: it may be difficult to select the proper area to cover with the curly brace, as too much or too little may be easily selected. It is easy to redo the selection, however the problem could be a fairly common occurrence and should be prevented rather than simply detected.Possible SolutionWhen the user drags the mouse to select the expression, if the user selects less than the expected number of operands, the system could check for terms close to where the brace began and ended and include them in the expression to be evaluated.Also, an alternative solution is to allow the user to click the operator he would like to evaluate and then determine the operands and make his calculations. RelationshipsHE5,HE6ObserverLyndsi Hughes, Joshua McCauleyHE21 -- ProblemNameApplet opens in new windowEvidenceHeuristic: Prevent ErrorsWhen loading a new instance of an applet it opens in a new window. Furthermore, the applet does not even load in this space.ExplanationWhen a new window opens it becomes another screen for the user to manage. This could become an issue for some users, causing them to close the browser window since it is perceived as no longer being needed. However, the browser must remain open to keep the applet running.SeverityMedium: There is a possibility that the user will close the browser window upon the opening of the applet window. This will cause the applet window to close, something that a novice user may not know.Possible SolutionDesign the applet to run from within the browser window. Or the web page that loads the applet could clearly state not to close the browser window.RelationshipsNoneSubmitted ByJoshua McCauleyHE22-- ProblemNameMisleading and confusing buttons.EvidenceHeuristic: Provide clearly marked exits/Speak the User’s LanguageAll action buttons that the user encounters are near the bottom of the applet. ExplanationThe user must search the page for the action buttons when working with the applet, especially if they are new to the interface. The user would be better served with the action buttons being moved to an area that their eyes are focused in. Also, the buttons should be more uniform in size.SeveritySmall-Medium: The user may end up spending a lot of time looking for the action buttons. This has the ability to make the applet less than desirable to use.Possible SolutionMove the action buttons to a more user friendly location, close to where their eyes are often focusing on and make the buttons of similar size. RelationshipsHE12Submitted ByJoshua McCauley, Raman FedarenkaHE23 – ProblemNamePop-up message box has misleading information.EvidenceHeuristic: Simple and natural dialogA redundant button is used.ExplanationIn pop-up message box on exit buttons “No” and “Cancel” perform the same action.SeverityMinor. Can cause confusion like which button to choose if user doesn’t want to exit.Possible solutionLeave only “Yes” and “No” buttons in the message box.RelationshipsHE1Submitted ByRaman Fedarenka ................
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