TU Wien:Advanced Internet Computing VU (Dustdar)/Prüfung 2022-01-17

Tuwel Test, Open Book, 35 minutes, max 40 points, random selection out of question pool.

• With services computing, loose coupling indicates the degree of dependency. Web services are loosely coupled. (1.0 points, true or false)

• This specification allows to synthesize complex Web Services from smaller ones which are interacting. (0.5 points, single choice)
  • WS-Coordination
  • BPEL
  • UDDI

• Docker is not an example of an OS-Level Virtualization technology. (0.5 points, true or false)

• Cloud computing is beneficial when considering the use cae of batch computational workloads. (0.5 points, true or false)

• Security concerns in IoT systems include non-repudiation. (0.5 points, true or false)

• Multi-access Edge Computing (MEC) is typically characterised by low reliability and volatility. (0.5 points, true or false)

• Software-as-a-Service and Platform-as-a-Service are better in terms of vendor lock-in than infrastructure-as-a-Service. (0.5 points, true or false)

• Federated learning provides a solution to the problem of providing incentives to devices to behave well - for example by contributing local model updates to a global model. (0.5 points, true or false)

• Within federated learning, submission of data by end-devices in a timely manner (often referred to as timeliness) is not an issue. (1.0 points, true or false)

• A great advantage of Software-as-a-Service is that it can be always be customized to one's needs. (0.5 points, true or false)

• An IoT application is in carge of continuously collecting data from thousands of environmental sensors distributed over a country, performing some initial filtering of the data to detect faulty sensor readings, and storing them for future processing. Where would you host the data filtering functionality? (1.5 points, single choice)
  • At the edge
  • On the cloud

• A robot control application works as follows: It receives sensing information from a mobile robot which is connected to the Internet over a Wi-Fi link, processes the sensing data, and decides in real time on an appropiate robot control action which it sends to the robot (e.g., instructs the robot to change tis direction to avoid an obstacle). Where would you execture the robot control application. (1.5 points, single choice)
  • On an edge computer or the robot itself
  • On a cloud virtual machine

• Within an IoT-Cloud application and from a service provider perspective, the edge should typically be considered as trusted. (1.0 points, true or false)

• Within services computing, a Message-oriented Middleware is an infrastructure for passing of data between applications using a common communication channel where messages are sent and received in an asynchronous manner. (0.5 points, true or false)

• It is more typical to execute a microservice in a virtual machine than in a container. (1.0 points, true or false)

• LPWAN offers connectivity with higher throughput compared to WAN. Wi-Fi is an example of an LPWAN technology. (1.0 points, true or false)

• Consider a supply-chain management system which involves interactions between mutiple entities (eg, customer, supplier, etc.), each one hosting a different set of web services. Web service choreography pertains to managing the control and data flow within each entity's organizational boundaries. (0.5 points, true or false)

• Within containerization, drivers for hardware are not shared. (0.5 points, true or false)

• When network neutrality is not enforced, IoT service providers can team up with network operators so that their services' traffic is preferentially treated. (1.0 points, true or false)

• You are the provider of a large social networking service. One of the many functions of this service is the generation of JSON Web Tokens, i.e., cryptographicaty-signed objects that can be used, e.g., for authenticating user requests to various API endpoints of your service. This function requires 100 MB RAM and is invoked 2.5 million times per month. Each time it is invoked, it runs for 0.1s. As a service provider, you have the following two options to host this function: (4 points)
  • Option 1: Lease an on-demand virtual machine from an laas provider and nost your function there. The cheapest offering which can fit your memory and other requirements costs 0.15 EUR/hour.
  • Option 2 Deploy your function at a Faas provider in this case, the following charges apply: Compute charges 0.000001 EUR per MB-s. Request charges 1 EUR per million requests.
  • You need to select the option with the minimum monthly cost (Assumpsions: A month has 30 days and both options there is no free tier.)
    • (1 point) Which of the two options has the minimum monthly cost? (1 or 2)
    • (3 points) What is the minimum monthly cost? Please enter a numerical value.

• The figure shows a redundant cloud deployment for a web application. The application can function properly if the load balancer is working, as well as at least one web server and at least one database server. (figure shows 1 load balancer, 2 web servers and 3 database clusters). (4 points, single choice)
  • Assume that the individual component availabilities are as given below:
    • availability(load_balancer)=0.98
    • availability(web_server)=0.99
    • availability(database)=0.93
  • What is the overall availability (A) of the system?
    • A > 0.78 and A < 0.97
    • A < 0.78
    • A > 0.97

• A cancer research institute wants to build a digital library of DNA (genome) samples from tens of thousands of patients for long-term research usage. This requires running a genome sequencing analysis on each of the samples independently. Assume that each individual sample analysis can be handled by a single large memory Amazon EC2 VM instance. A sample analysis can last for hours, but can be stopped and resumed arbitrarily. The institute's primary concern is to complete the sample library at the smallest possible cost. Based on the provided information, which EC2 instance type would you use to implement the described use case? Select the one that is most applicable. (4 points, single choice)
  • On-demand
  • Dedicated
  • Reserved
  • Sport instance

• Consider a smart parking service which works as follows. A camera is capturing images from parking spots and transmits them to a remote server at a rate of 10 images/s. The server performs an image processing task where it identifies if the parking spot is occupied and, if so, it detects the license plate of the respective car. Which networking technology would you select to connect the camera device to the remote server? (4.0 points, single choice)
  • 4G
  • NB-loT
  • LoRaWAN

• A provider of computational resources (e.g., the operator of an IT center offering computational resources to customers) would rather provide virtualized resources like Virtual Machines instead of offering Physical Machines for reasons of (select all statements below that apply): (2.0 points, multiple choice)
  • Backend paralellization
  • Customer security
  • Consolidation for energy consumption
  • Multitenancy

• Microservices are a vairant of the service-oriented architecture (SOA) structural style. Select all of the statements below that are applicable. (2.0 points, multiple choice)
  • Microservices may feature individual data backends.
  • Increased latency is a problem when adopting microservices.
  • Microservices can be easily scaled.
  • Adopting microservices eases the burden of integration testing.
  • Microservices feature good fault isolation.

• Assume a scenario where 3 mobile devices participate in a federated learning task Before a given training round, the server selects a subset of these devices, which will then perform training on their local data and submit model updates to the server. It is possible that a selected device fails to submit a report at the end of the round (eg, it may run out of battery during the process, lose its connectivity, etc.). For each device, the probability that it successfully delivers its report in a round is given below. (4.0 points)
  • Devices:
    • Device 1: p1 = 0.1
    • Device 2: p2 = 0.6
    • Device 3: p3 = 0.4
  • At the same time, each device has a fixed cost to participate in a round. If selected, the cost of each device is given below:
  • Costs:
    • Device 1: c1 = 10
    • Device 2: c2 = 2
    • Device 3: c3 = 20
  • The server needs to select the subset of devices to participate in the round which minimizes the total cost under the constraint that the expected number of reports that will be received by the server is at least E = 1 (The total cost is defined as the sum of the costs of all devices that participate in a round if a device is not selected, it does not contribute to the overall cost.)
  • (a) What is the optimal subset of devices that the server should select? Provide your answer in the following format XY. For example of the server selects devices 1 and 3, your answer should be (1,3), if the server selects device 2 your answer should be (2) etc. If there is no feasible solution, your answer should be (). This format is strict: Do not use whitespace characters in your answer; keep the paretheses.
  • (b) What is the cost of the optimal solution? Provide a numerical value. If there is no feasible solution, answer with 0.
  • (c) What is the expected number of reports that the server will receive in this round under the optimal solution? Provide a numerical value. If there is no feasible solution, answer with 0.
• According to the ETSI standard specifications for Multi-access Edge Computing, when a customer selects to create an application instance via a Customer Facing Service portal, the application package should have already been onboarded. (0.5 points, true or false)
• Xen and Docker are both examples of OS-Level Virtualization technologies. (0.5 points, true or false)
• Microservice architectures are characterized by a small invocation depth. (0.5 points, true or false)