Computer Science Previous Year Questions (page 13)

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"Any two numbers" means for all x and for all y, and "can be added" means there exists a sum z: (∀x)(∀y)(∃z)(x + y = z).

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Pattern recognition first acquires data, then extracts features, then matches them against stored patterns, and finally classifies.

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Spoofing is disguising a communication from an unknown source (e.g., a forged email address or IP) to look as if it comes from a trusted source.

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Sandboxing runs untrusted programs in a restricted, controlled environment so they cannot harm the rest of the system.

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A patch is a software update that fixes bugs or security holes, so software updates are also called patching.

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A honeypot is a decoy system set up to lure attackers so their methods can be observed and studied.

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A database includes its schema, data, relationships and constraints. A frontend is the user interface application, not part of the database.

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ROUND() is a numeric function and LENGTH() is a character function. INSERT() (e.g., in MySQL) is a string function, not a numeric one.

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A self join joins a table to itself, usually using aliases, e.g., to pair employees with their managers in the same table.

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A quaternary relationship involves 4 entity sets (binary is 2, ternary is 3).

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ACID stands for Atomicity, Consistency, Isolation and Durability. "Instance" is not one of them.

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GROUP BY puts rows with the same values in the given column(s) into groups, usually for aggregates like SUM or COUNT.

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Database models include hierarchical, network, relational and object-oriented. There is no "inheritance model".

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A data dictionary is a metadata repository that holds definitions, rules and descriptions of the data. It is not a memory area for storing data.

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SSL stands for Secure Sockets Layer, the protocol (now replaced by TLS) that encrypts traffic between a browser and a server.

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CRM covers the methods, technology and capabilities a business uses to manage and analyse its interactions with customers.

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Ciphertext is plaintext transformed by an encryption algorithm. Kerckhoffs's principle says the algorithm should be public and only the key secret, so II is false.

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Block cipher modes include ECB, CBC, CFB, OFB and CTR. "Stream (Stem) cipher mode" is not one of them.

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In distributed computing, the components of a software system are shared among multiple networked computers that work together.

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LANs, mobile networks and the Internet are distributed systems of separate networked computers. Parallel computing usually uses processors sharing memory in one machine, so it is counted as different.

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Video games, flight simulators and logic-gate simulations all model real systems. A computer table is just furniture.

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Simulation imitates how a real-world process or system behaves over time, using a model.

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In neural network theory a biological neuron is a cell that receives electrochemical signals from many sources (through dendrites) and transmits electrical impulses to other neurons.

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An axon is the long cylindrical fibre that carries impulses away from a neuron to other neurons.

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Distributed systems are loosely coupled because each node has its own memory and they communicate over a network. Parallel (multiprocessor) systems are tightly coupled because they share memory and a clock.

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In Flynn's taxonomy, MISD means Multiple Instruction stream, Single Data stream.

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Link analysis, database segmentation (clustering) and predictive modelling are data mining techniques. Evaluation is a general step, not a mining technique.

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R, Python and Weka are widely used for data mining. BASIC is an old general-purpose language, not a data mining tool.

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Flooding sends every incoming packet out on every outgoing line except the one it arrived on.

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Satellite-to-earth transmission uses the downlink frequency, and earth-to-satellite uses the uplink frequency.

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Non-adaptive (static) routing algorithms decide routes in advance and ignore current traffic and topology. Adaptive algorithms react to them.

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Runge-Kutta methods numerically solve ordinary differential equations (initial value problems).

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The keyed 1.571 comes from x³ + 4x − 9 = 0 (the cube seems lost in the source): f(1) = −4, f'(1) = 3 + 4 = 7, so x₁ = 1 + 4/7 ≈ 1.571. With x² instead, x₁ would be 1.667.

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Computational linguistics is the scientific study of language from a computational point of view, i.e., computers processing human language.

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In f(x, y), x and y are spatial coordinates, and the amplitude of f at any point is the intensity (grey level) of the image there.

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Digitizing the coordinates is sampling, and digitizing the amplitude values is quantization.

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The motivation comes from the pleasure of doing the activity itself, not from an outside reward, so it is intrinsic motivation.

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Both statements are correct: classical conditioning conditions elicited (respondent) behaviour, and operant conditioning conditions emitted behaviour. So neither is incorrect.

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Value education can be given through skits and dramas, morning assemblies, and as a compulsory subject, so all three are correct.

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Teaching and instruction are planned and organised activities meant to develop learners' thinking power.

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Braille, arithmetic frames (Taylor frame) and the abacus help visually impaired children. A hearing aid is for hearing impairment.

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Ideas for drama can come from imagination, the environment, history/literature and movies, so all four sources apply.

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Following the key, statement II (providing plenty of art material so the child can choose, pick and innovate) describes facilitation, and statement I is treated as not correct.

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Oral and written tests are both valid ways to assess language learning, so neither is "not" a method of assessment.

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Reading material should be meaningful and suited to the child's level, and in a language the child is familiar with. Both points are needed.

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In a theme-based ECCE programme, teachers observe children's interests, needs and pace of development, and build nurturing, positive relationships. Both are teacher roles.

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Major types of children's play include functional (practice), constructive and dramatic/pretend play, so all three are correct.

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Matching, sorting/classifying, comparing and seriation are pre-number concepts developed in the preschool years.

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Proportional reasoning needs abstract thought, which develops in Piaget's formal operational stage (11+ years).