questions","basePath":"/gcse/computer-science/aqa/data-compression/questions","formulaUrl":null,"initialIndex":52,"initialQuestionWindow":[{"id":"d6787a37-d331-4efd-bb8d-a3228aff8346","revisionId":"0f607622-9c61-4bf3-bf46-9588c25b564e","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"ddf37f13-a3d3-4ebc-b658-d0f1677767de","label":null,"content":"Using the Huffman tree in Figure 1, complete the table to show the Huffman coding for the characters **E**, **SPACE**, and **M**.\n\n![A Huffman tree diagram for the text 'TEA TIME'](https://assets.mathsgenie.co.uk/aqa-qb/acd907a4-cca5-4232-af36-66d6af8c0bc0.png)\n\n| Character | Huffman Coding |\n| :--- | :--- |\n| E | |\n| SPACE | |\n| M | |","markscheme":"- Identifies the correct Huffman code for **E** as $11$ A1\n- Identifies the correct Huffman code for **SPACE** as $001$ A1\n- Identifies the correct Huffman code for **M** as $011$ A1","marks":3,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"dd3cd682-357f-4a51-9339-0062ff6b2140","revisionId":"bb5ff7ba-c465-4fee-9307-6012fb14e213","questionNumber":null,"questionType":"LA","specification":"A digital image sensor transmits a single line of pixel data represented by the following sequence of characters:\n\n`WWWWWWBBBBBGGGGGGGGW`","difficulty":3,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"1e767477-089d-467d-b38c-6fc84b0a5ef2","label":null,"content":"State a run-length encoding (RLE) representation of this sequence.","markscheme":"- Identifies the correct frequency of each consecutive character run: six Ws, five Bs, eight Gs, and one W M1\n- Compiles these into a valid, consistent RLE representation, such as `6W5B8G1W` or `W6B5G8W1` A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"dd506faf-1513-4d35-b0b0-0cf286ed4d41","revisionId":"b688a02c-1a75-4fcd-a416-3c5ccfae119b","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"bf52a289-6204-422c-ab6d-417d36b29549","label":null,"content":"A telemetry payload transmits the scientific logging string shown in **Figure 1**:\n\n### Figure 1\n`QUANTUM_ENTANGLEMENT`\n\nWhen a custom Huffman tree is constructed for this 20-character string, the string can be represented using exactly 74 bits.\n\nDetermine the number of bits that are **saved** when Huffman coding is used rather than standard 8-bit ASCII to encode this string.\n\nYou **must** show your working.","markscheme":"- Calculates the ASCII representation size: $20 \\times 8 = 160$ bits M1\n- Subtracts the Huffman bits from the ASCII total to find the correct number of bits saved: $160 - 74 = 86$ bits A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_computer_science__aqa","summaries":[{"id":"01aceeda-575c-4ced-bc96-ba092de79c7e","difficultyBand":"medium","calculatorUse":null},{"id":"03fe5cea-6efd-45d9-aa60-75964ab4705a","difficultyBand":"easy","calculatorUse":null},{"id":"07d36a1a-5c14-476d-80ea-f2079e422bfb","difficultyBand":"easy","calculatorUse":null},{"id":"0ab264e5-e293-4736-91b6-fd500dfb6b02","difficultyBand":"easy","calculatorUse":null},{"id":"0fc37e4c-7cae-4c1a-9fb3-66f966107332","difficultyBand":"medium","calculatorUse":null},{"id":"1cb71686-bddf-4766-bac7-646e97cdb718","difficultyBand":"easy","calculatorUse":null},{"id":"1d080ea0-8d9f-41a4-ae48-50a80dde2388","difficultyBand":"medium","calculatorUse":null},{"id":"2388faa7-f6e4-47a9-a80f-dc5cf1f23147","difficultyBand":"medium","calculatorUse":null},{"id":"2517e7f4-de71-4ffb-ad43-2cd8a3eaa98f","difficu

Data compression

Question 36

Data compression Questions

Data compression

Question 36

Data compression Questions