###BeginCaseStudy###
Testlet 1
Background
You are developing a web-based solution that students and teachers can use to collaborate on written
assignments. Teachers can also use the solution to detect potential plagiarism, and they can manage
assignments and data by using locally accessible network shares.
Business Requirements
The solution consists of three parts: a website where students work on assignments and where teachers view
and grade assignments, the plagiarism detection service, and a connector service to manage data by using a
network share.
The system availability agreement states that operating hours are weekdays between midnight on Sunday and
midnight on Friday.
Plagiarism Service
The plagiarism detection portion of the solution compares a new work against a repository of existing works.
The initial dataset contains a large database of existing works. Teachers upload additional works. In addition,
the service itself searches for other works and adds those works to the repository.
Technical Requirements
Website
The website for the solution must run on an Azure web role.
Plagiarism Service
The plagiarism detection service runs on an Azure worker role. The computation uses a random number
generator. Certain values can result in an infinite loop, so if a particular work item takes longer than one hour to
process, other instances of the service must be able to process the work item. The Azure worker role must fully
utilize all available CPU cores. Computation results are cached in local storage resources to reduce
computation time.
Repository of Existing Works
The plagiarism detection service works by comparing student submissions against a repository of existing
works by using a custom matching algorithm. The master copies of the works are stored in Azure blob storage.
A daily process synchronizes files between blob storage and a file share on a virtual machine (VM). As part of
this synchronization, the ExistingWorkRepository object adds the files to Azure Cache to improve the display
performance of the website. If a student’s submission is overdue, the Late property is set to the number of days
that the work is overdue. Work files can be downloaded by using the Work action of the TeacherController
object
Network Connector
Clients can interact with files that are stored on the VM by using a network share. The network permissions are
configured in a startup task in the plagiarism detection service.
Service Monitoring
The CPU of the system on which the plagiarism detection service runs usually limits the plagiarism detection
service. However, certain combinations of input can cause memory issues, which results in decreased
performance. The average time for a given computation is 45 seconds. Unexpected results during
computations might cause a memory dump. Memory dump files are stored in the Windows temporary folder on
the VM that hosts the worker role.
Security
Only valid users of the solution must be able to view content that users submit. Privacy regulations require that
all content that users submit must be retained only in Azure Storage. All documents that students upload must
be signed by using a certificate named DocCert that is installed in both the worker role and the web role.
Solution Development
You use Microsoft Visual Studio 2013 and the Azure emulator to develop and test both the compute component
and the storage component. New versions of the solution must undergo testing by using production data.Scaling
During non-operating hours, the plagiarism detection service should not use more than 40 CPU cores. During
operating hours, the plagiarism detection service should automatically scale when 500 work items are waiting to
be processed. To facilitate maintenance of the system, no plagiarism detection work should occur during nonoperating hours. All ASP.NET MVC actions must support files that are up to 2 GB in size.
Biographical Information
Biographical information about students and teachers is stored in a Microsoft Azure SQL database. All services
run in the US West region. The plagiarism detection service runs on Extra Large instances.
Solution Structure
Relevant portions of the solution files are shown in the following code segments. Line numbers in the code
segments are included for reference only and include a two-character prefix that denotes the specific file to
which the line belongs.
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HOTSPOT
You need to find all existing works about World History that are overdue and are stored in the repository.
How should you complete the relevant code? To answer, select the appropriate option or options in the answerarea.
Hot Area:
Answer: 