IBDP Computer Science A4.4 Ethical considerations SL Paper 2 - New Syllabus
Question
While working on an assignment task for History of the Americas, Brooke enters a question into a search engine (Figure 7).
The search returns 173000 results in 0.043 seconds.
Another student indicated that Brooke would obtain better results using keywords rather than a search phrase.
(a) Outline why keywords would be used in a search rather than a phrase.
Web crawling indexes webpages in the search engine’s database (Figure 8). The two web crawling methods used are a breadth-first crawl and a depth-first crawl.
(b) In Figure 8, A has not been previously visited. State the first three webpages visited in a breadth-first search.
(c) Outline one reason why search engines use a breadth-first search.
As the web crawler traverses the pages in a website it collects data. This is used to form the metrics data for search rankings.
(d) Identify two features of the PageRank algorithm.
Many web developers attempt to optimize the search results for their site.
(e) Explain the impact for DP History students such as Brooke if the web developer uses black hat search engine optimization techniques.
Most-appropriate topic codes (IBDP Computer Science HL Paper 2):
• A2.1: Network fundamentals — Parts (a), (b), (c) and (d)
• A4.4: Ethical considerations — Part (e)
▶️ Answer/Explanation
(a)
For the correct answer:
- Keywords are often matched with the metatag keywords and description as well as the page content, increasing the accuracy of the search.
- Use of keywords helps to clarify the searcher’s thinking.
- Using a phrase adds additional terms that are either ignored by the search engine or could provide false-positive results.
- Keywords can reduce contextual differences derived from the use of language in the results.
When Brooke types a full natural-language question, irrelevant words may dilute the focus of the search. Reducing the query to important keywords allows the search engine to match the terms more precisely against indexed page content and metadata.
(b)
For the correct answer:
A-B-E
In a breadth-first crawl starting from node A, the crawler visits A first and then explores webpages at the next depth level before moving deeper into the graph. Therefore, the first three webpages visited are A, B and E.
(c)
For the correct answer (any one):
- The breadth-first crawl ensures that all pages at a certain depth are indexed before moving deeper.
- It visits the links at the current level before proceeding to a deeper level.
- It can prioritize higher-level pages that are more likely to contain significant information and links to other relevant content.
- It reduces the possibility of following one very deep chain of links while important higher-level pages remain unindexed.
Breadth-first crawling systematically explores webpages by depth, allowing a search engine to obtain a broad snapshot of relevant pages rather than following one link path deeply before examining other pages.
(d)
For the correct answer (any two):
- PageRank is a numerical value representing the importance of a webpage.
- A damping factor is applied to the calculation.
- The PageRank algorithm is recursive.
- PageRank uses the PageRank of incoming/outgoing links.
PageRank treats links as indicators of the importance of webpages. Its recursive calculation means that the rank of a webpage depends partly on the ranks of webpages linking to it. A damping factor is also used to model the probability that a user continues following links rather than starting a new search.
(e)
For the correct answer:
Information inaccuracy: Black hat SEO can manipulate search rankings, for example through keyword stuffing. This may cause inaccurate or irrelevant websites to appear prominently in Brooke’s results.
Time and resources: Brooke may waste time visiting websites that do not contain the required historical information. Additional bandwidth may also be used while accessing irrelevant pages.
Security: Some manipulated websites may contain malware or other security threats, potentially exposing Brooke’s device or personal information to harm.
Academic impact: Brooke could unknowingly use unreliable or inaccurate information in her History of the Americas assignment, reducing the quality and validity of her research.
Therefore, black hat SEO can negatively affect students by reducing the relevance and reliability of search results and increasing the risk of exposure to inappropriate or unsafe websites.