Question 1

In artificial intelligence terminology, what type of repository does AI primarily operate on, in contrast to conventional data-processing systems that focus on raw records and transactions?

Accepted Answer

Introduction / Context: Artificial intelligence systems aim to mimic aspects of human reasoning by using structured representations of facts, rules, and relationships. Instead of merely storing rows and columns of data, AI leverages formal knowledge to infer new conclusions, answer queries, and explain decisions. Given Data / Assumptions: We contrast traditional databases with AI-oriented repositories. AI systems may use production rules, ontologies, or semantic networks. We are identifying the term that best captures this repository. Concept / Approach: A knowledge base stores assertions (facts) and inference rules in a form the reasoning engine (inference engine) can use. Databases, while sometimes enriched with constraints and triggers, are not primarily designed for inference over symbolic knowledge. Languages such as PROLOG and LISP are tools; they are not the repositories themselves. Therefore, the correct choice is 'knowledge base.' Step-by-Step Solution: 1) Recognize the repository AI relies upon: structured knowledge, not just raw data.2) Distinguish implementation languages (PROLOG/LISP) from the conceptual store.3) Select 'Knowledge base' as the appropriate term. Verification / Alternative check: Expert systems and knowledge graphs exemplify knowledge bases driving inference and question answering. Why Other Options Are Wrong: Character base: not a standard concept.PROLOG/LISP: languages or paradigms, not repositories.None: a correct option exists. Common Pitfalls: Confusing storage mechanisms with reasoning engines; assuming any data store equals knowledge. Final Answer: Knowledge base

Question 2

In 3D computer graphics terminology, a display of a volumetric model that renders every edge of the geometry without shaded faces is known as which type of representation?

Accepted Answer

Introduction / Context: 3D models can be rendered in several modes for different purposes such as editing, analysis, and presentation. A common view during design is one that emphasizes topology and geometry by drawing edges without surface shading. Understanding the terminology for these modes is foundational in CAD and graphics. Given Data / Assumptions: The model is volumetric (has 3D extent). The display mode shows all edges only—no filled faces or shading. We must identify the standard name of this representation. Concept / Approach: A 'wire-frame' view depicts only the edges, resembling a skeletal frame of lines. In contrast, 'surface' or 'solid' models imply additional information like face orientation, normals, and volumetric properties, which typically appear in shaded or hidden-line modes. Wire-frame is efficient for visualizing complex geometry and internal structures quickly but may suffer from visual clutter. Step-by-Step Solution: 1) Match the description (all edges visible) to representation types.2) Exclude surface/solid, which focus on faces and volume properties.3) Select 'Wire-frame' as the correct term. Verification / Alternative check: Most CAD packages include view modes explicitly labeled 'wireframe,' 'shaded,' and 'hidden-line,' confirming the standard terminology. Why Other Options Are Wrong: Surface model: concerns faces; not only edges.3-D model: too generic; all options refer to 3D contexts.Solid model: implies volumetric semantics; not just edges.None: a correct term exists. Common Pitfalls: Confusing wire-frame with hidden-line; in hidden-line, occluded edges are suppressed, while pure wire-frame shows all edges. Final Answer: Wire-frame

Question 3

In digital logic, what is the primary function of an encoder device?

Accepted Answer

Introduction / Context: Encoders and decoders are fundamental building blocks in digital systems. Recognizing the direction of conversion—one-hot or multi-line inputs to compact binary codes—helps when designing keypads, priority circuits, and address generators. Given Data / Assumptions: An encoder takes multiple mutually exclusive inputs (e.g., keys 0–9) and outputs a binary code representing the active input. A decoder performs the inverse operation, expanding a binary code into multiple output lines. We identify the correct functional description of an encoder. Concept / Approach: A classic example is a 10-to-4 keypad encoder that maps one pressed key to a 4-bit binary output. Additional features like 'priority' handle simultaneous inputs. Telegraphy is unrelated, and an encoder’s number of inputs is not restricted to four. Step-by-Step Solution: 1) Recall definitions: encoder vs. decoder.2) Map practical examples (keypad) to function.3) Select the option describing multi-line to binary conversion. Verification / Alternative check: Digital design texts specify n-to-log2(n) encoders and log2(n)-to-n decoders, validating the function described. Why Other Options Are Wrong: Telegraph signals: an unrelated communications domain.Converts binary to decimal: that is a decoder, not an encoder.Only four keys: false; encoders can have many inputs.None: incorrect since a correct description is provided. Common Pitfalls: Confusing encoders with multiplexers; while related concepts exist, their functions differ. Final Answer: It converts an input (from one of many lines or keys) into a binary number

Question 4

When you must persuade senior management to approve an information-systems initiative, which single document is most important to present as the basis for decision making?

Accepted Answer

Introduction / Context: Securing executive sponsorship requires more than enthusiasm; it demands a rigorous, decision-ready document. Management needs a balanced view of value, cost, risk, and strategic alignment to authorize funding and resources. This is the role of a structured project evaluation (often called a feasibility or business case report). Given Data / Assumptions: The goal is to obtain a go/no-go decision. Leaders expect quantified benefits, cost estimates, timelines, risks, and clear recommendations. The document should be comprehensive yet concise, integrating inputs from stakeholders and technical teams. Concept / Approach: A project evaluation synthesizes the problem statement, proposed alternatives, economic analysis (cost–benefit, ROI, payback), technical feasibility, operational impact, risks, and mitigation plans. It is more actionable than a mere problem summary and broader than a financing method. Purchasing procedures are downstream tasks once the project is approved. Step-by-Step Solution: 1) Define the decision: should management authorize the project?2) Identify required content: business need, options, costs/benefits, risks, and recommendation.3) Recognize the document that integrates all these elements: a project evaluation (business case/feasibility report).4) Select the corresponding option. Verification / Alternative check: Portfolio and PMO practices require business cases or feasibility reports before allocating capital, confirming this as the key artifact. Why Other Options Are Wrong: Method for financing: important but insufficient alone.Problem summary: necessary, but it lacks analysis and recommendation.Procedure for purchase: relevant only after approval.None: incorrect because a definitive best choice exists. Common Pitfalls: Presenting technical details without business value; omitting risk and change-management costs; failing to compare credible alternatives. Final Answer: A project evaluation presenting costs, benefits, risks, and recommendations

Question 5

In industrial control, what is a sequence controller, and which statement best describes its primary role in time-based on/off operations?

Accepted Answer

Introduction / Context: Sequence controllers are common in industrial automation for packaging lines, batch processes, machine cycles, and safety interlocks. Unlike continuous controllers that regulate a variable to a setpoint, a sequence controller executes a predefined series of steps, often actuating devices on or off based on time, counters, or discrete conditions. This question checks whether you can distinguish time/step-driven logic from other control types. Given Data / Assumptions: Applications include start–stop cycles, valve open/close, conveyor advances, and timed dwell periods. Implementation may be via PLC ladder logic, function blocks, sequential function charts, or dedicated sequencers. Outputs are primarily discrete (on/off), though analog checks can be used as interlocks. Concept / Approach: A sequence controller advances through a list of states: Step 1, Step 2, … Each step triggers discrete outputs and waits for a condition (time elapsed, sensor made, counter reached) before proceeding. This differs from PID loops that continuously compute control effort to minimize error. Therefore, the best description highlights on/off actions relative to time or events. Step-by-Step Solution: Identify the control objective: orchestrate actions in order (e.g., clamp → drill → unclamp). Recognize outputs are discrete devices (solenoids, contactors) toggled on/off. Note transitions are governed by timers or discrete conditions. Select the statement that names time/step-based on/off control as the essence. Verification / Alternative check: PLC manuals describe sequencers/timed state machines that map directly to on/off steps; this validates the choice. Why Other Options Are Wrong: A: Modern tools make sequencing straightforward; difficulty is not inherent. B: Controllers are electronic or software-based; purely mechanical cams are legacy. C: Sequencers are still widespread in packaging, batch, and robotics. E: PID is continuous control; not the defining feature of sequence control. Common Pitfalls: Confusing sequence control (discrete steps) with feedback regulation; mixing the two without clear interlocks can cause unsafe transitions. Final Answer: It performs on/off control functions according to a defined time or step sequence

Question 6

The insect-type hexapod robot Attila (approximately 1.7 kg) was designed as an advanced version of Genghis. How many onboard microprocessors did Attila carry?

Accepted Answer

Introduction / Context: Classic MIT hexapod robots—Genghis and its successor Attila—are milestones in behavior-based robotics and subsumption architecture. Attila increased sophistication with more sensors, actuators, and distributed processing. Knowing its processor count helps learners appreciate distributed control in early autonomous platforms. Given Data / Assumptions: Attila is a six-legged (hexapod) robot around 1.6–1.7 kg in mass. It used numerous sensors and actuators coordinated by multiple onboard processors. The question asks for the specific number of onboard microprocessors. Concept / Approach: Attila exemplified distribution of computation: each local controller handled low-level behaviors (e.g., leg control, reflexes), while higher-level layers coordinated locomotion and navigation. The architecture favored robustness and parallelism, reducing reliance on a single central CPU. Step-by-Step Solution: Recall authoritative descriptions from robotics literature on Attila’s hardware. Identify the documented processor count used to run layered behaviors and manage sensors/actuators. Select the matching numeric option. Verification / Alternative check: Published technical sources on Attila report 11 onboard processors coordinating 150+ sensors and over 20 actuators, confirming the answer aligns with the historical design record. Why Other Options Are Wrong: 10/15/33/7: These numbers do not match documented specifications for Attila’s distributed computing; they are distractors around the true value. Common Pitfalls: Confusing Attila with Genghis or other hexapods that used fewer processors; conflating sensor count with processor count; assuming a single powerful CPU rather than many simple ones. Final Answer: 11

Question 7

Looking ahead, which transmission form most accurately describes the dominant trend for future communications across networks and media?

Accepted Answer

Introduction / Context: Modern communications—from mobile networks to the Internet backbone and industrial fieldbuses—overwhelmingly favor digital encoding. Even when the physical layer is analog (e.g., radio), information is carried as digital bit streams with modulation schemes designed for robustness, security, and efficiency. Given Data / Assumptions: We are comparing transmission form (digital vs analog), not only the medium. Future networks continue to expand in bandwidth using fiber, wireless, and high-speed copper where needed. Error correction, encryption, and multiplexing are easier with digital representations. Concept / Approach: Digital bit streams enable channel coding, compression, and routing. Physical media include optical fiber, RF spectrum, and copper, but the payload remains digital. Analog is still used for niche or legacy systems, yet the trend line points to end-to-end digital ecosystems from sensor to cloud. Step-by-Step Solution: Identify long-term drivers: capacity, reliability, security, and integration with computing. Map these to digital techniques (FEC, encryption, packet switching). Select the option that captures the overarching trend. Verification / Alternative check: Telecom standards (Ethernet, 4G/5G, Wi-Fi, GPON) use digital frames/packets even over analog carriers, confirming that digital bit-stream encoded data dominates. Why Other Options Are Wrong: B: Analog persists but is not the dominant future mode. C: Metallic telephone lines are declining relative to fiber and wireless. D/E: Mutually inconsistent and inaccurate as broad predictions. Common Pitfalls: Confusing “analog carrier” with “analog information”; digital information rides on analog carriers but remains digitally encoded end-to-end. Final Answer: Digital bit-stream encoded data

Question 8

In image processing and computer vision, the technique that localizes an object and analyzes it across a series of progressively coarser, redundant layers is called:

Accepted Answer

Introduction / Context: Multiscale analysis is central to image processing. By repeatedly smoothing and subsampling an image, algorithms create a stack of lower-resolution versions. Objects can be detected or tracked consistently across scales, improving robustness to size changes and noise. The commonly used construction is the Gaussian pyramid, from which other pyramids (like Laplacian) are derived. Given Data / Assumptions: Goal: localize and analyze objects at multiple resolutions. Layers are redundant (coarser levels summarize finer details). Gaussian smoothing precedes subsampling to avoid aliasing. Concept / Approach: A Gaussian pyramid is built by convolving the image with a Gaussian kernel and downsampling iteratively. This yields a hierarchy used for scale-space analysis, feature detection, and coarse-to-fine search. The Laplacian pyramid (differences between levels) is often computed from the Gaussian stack for compression or blending. Step-by-Step Solution: Start with the original image (level 0). Apply Gaussian smoothing; downsample to form level 1. Repeat to form additional levels (level 2, 3, …). Search or analyze at coarse levels first, then refine at finer levels. Verification / Alternative check: Standard texts present Gaussian pyramids for coarse-to-fine optical flow, image registration, and object detection; this matches the description of redundant multiresolution layers. Why Other Options Are Wrong: A: The Turing test evaluates machine intelligence, unrelated to vision pyramids. B: “Pyramid representation” is generic; the specific, canonical construction here is Gaussian. D: “Maxwell pyramid” is not a standard multiscale term in vision. E: Not applicable because a well-known technique fits. Common Pitfalls: Skipping pre-subsampling smoothing causes aliasing; confusing Gaussian and Laplacian pyramids—the latter is derived from the former. Final Answer: Gaussian pyramid

Question 9

In human–computer interaction with CRT or display screens, direct operator interaction with the displayed region is accomplished via which device or interface?

Accepted Answer

Introduction / Context: Direct manipulation interfaces let users interact with on-screen objects without intermediate devices. The quintessential example is the touch-sensitive display, where the user’s finger (or a compatible stylus) contacts the screen surface to make selections, drag items, or invoke commands. Given Data / Assumptions: “Directly with the CRT” means input occurs on the screen surface itself. We compare various input devices and internal display mechanisms. Touch technology can be resistive, capacitive, infrared, or surface acoustic wave. Concept / Approach: A touch terminal integrates a touch sensor over the display, providing immediate, spatially mapped input. This differs from a digitizing tablet (off-screen), vector scanning (a drawing method inside the CRT), or a separate stylus on paper. Touch enables intuitive pointing, selection, and gestures mapped to screen coordinates. Step-by-Step Solution: Identify which option collects input at the same place as visual output. Match “direct interaction” with “on-screen touch.” Exclude devices not operating on the display surface. Choose the touch terminal. Verification / Alternative check: HCI literature classifies touchscreens as direct-input devices with zero or minimal spatial indirection, validating the selection. Why Other Options Are Wrong: A: Digitizing tablets are indirect; the hand moves on a pad, not the screen. B: Vector scanning is a rendering method, not a user input mechanism. C: A stylus on paper does not interact with the CRT. E: Not applicable since a correct choice exists. Common Pitfalls: Confusing pen displays (which are also direct) with generic styli on paper; the key is input on the display surface itself. Final Answer: A touch terminal (touch-sensitive screen)

Question 10

For pick-and-place industrial robots, what is a plausible best-case positioning accuracy achievable on high-precision systems?

Accepted Answer

Introduction / Context: Accuracy and repeatability are critical specifications for pick-and-place robots used in electronics assembly, metrology, and micro-manufacturing. Best-in-class systems can position parts within microns, enabling tasks such as die bonding or precision inspection. The question asks you to recognize a realistic best-case figure in inches. Given Data / Assumptions: We are referring to high-precision, well-calibrated systems under controlled conditions. Accuracy and repeatability are often specified separately; values may differ. Environmental controls (temperature, vibration) and calibration influence results. Concept / Approach: Top-tier Cartesian or SCARA pick-and-place platforms can deliver positioning accuracy and repeatability on the order of tens of micrometers. The value +0.0005 inches corresponds to about 12.7 micrometers, which is within the realm of precision assembly robots. Larger figures (e.g., 0.05 inches) are suited to less precise handling and do not represent “as good as” capability. Step-by-Step Solution: Convert candidate values to micrometers to sanity-check magnitudes. 0.0005 in ≈ 12.7 µm; 0.008 in ≈ 203 µm; 0.05 in ≈ 1270 µm. Select the smallest credible error for best-case high-precision systems. Choose +0.0005 inches. Verification / Alternative check: Vendor datasheets for precision pick-and-place and SCARA arms list repeatability in the 5–20 µm range, consistent with the +0.0005 inches figure as a plausible best case. Why Other Options Are Wrong: B: +0.05 inches is far too coarse for precision pick-and-place. C: 0.008 inches is much larger than best-case specifications. D: A percentage error is not a standard absolute positioning specification here. E: Not applicable since a credible figure exists. Common Pitfalls: Confusing accuracy with repeatability; a robot may be very repeatable yet less accurate without calibration or vision correction. Final Answer: + 0.0005 inches

Question 11

Which statement about integrated circuits (ICs) is correct in the context of electronics history and terminology?

Accepted Answer

Introduction / Context: The integrated circuit (IC) is a foundational technology that condensed multiple electronic components onto a single semiconductor substrate. Understanding accurate historical relationships and common terminology improves clarity in technical communication. Given Data / Assumptions: Transistors historically predate integrated circuits. “Chip” is widely used as a synonym for an IC. ICs indeed transformed electronics by increasing complexity per unit area and reducing cost. Concept / Approach: We need exactly one correct option. Two statements are true in general (ICs are called chips; ICs revolutionized electronics), but the option pairing in D incorrectly couples a true statement with a false one, making D invalid. The safest single, unambiguous truth is that an IC is commonly called a “chip.” Step-by-Step Solution: Confirm chronology: the transistor (late 1940s) predates mass IC fabrication (late 1950s onward). Identify the statement that is precise and terminologically correct. Avoid combinations that include false historical claims. Select “An integrated circuit is often called a ‘chip’”. Verification / Alternative check: Electronics references consistently use “chip” as shorthand for ICs and place transistor invention before IC development, verifying our choices. Why Other Options Are Wrong: B: Reverses history; transistors enabled ICs, not the other way around. C: While true, this standalone truth would create multiple correct answers with A; to maintain a single correct option set, we select A as the precise, terminological fact. D: Contains a false component, invalidating the pair. E: Incorrect because A is accurate. Common Pitfalls: Allowing multiple correct answers in MCQs; ensure distractors do not accidentally become true in general contexts. Final Answer: An integrated circuit is often called a “chip”

Question 12

In the original concept for a general-purpose CAD system architecture, what should the system provide to support users and applications effectively?

Accepted Answer

Introduction / Context: Computer-Aided Design (CAD) platforms are more than drawing tools; they are extensible environments. A solid CAD architecture must orchestrate user interaction, host application modules (e.g., parametric modeling, simulation), and supply core utilities that standardize geometry, graphics, file I/O, and constraints. Given Data / Assumptions: Users interact through devices (mouse, tablet, touch) and commands. Applications extend capabilities: drafting, solids, surfaces, simulation. Core services include geometry kernels, graphics pipelines, and resource managers. Concept / Approach: An effective CAD system is a layered stack: at the bottom, system utilities; above, an application framework; at the top, an interaction layer that translates user actions into model edits. Therefore, all three elements in options A–C are essential and collectively define the platform’s capability envelope. Step-by-Step Solution: Determine the architectural roles (interaction, application hosting, utilities). Map each role to a provided capability in options A–C. Since all are necessary, choose the inclusive option. Verification / Alternative check: Vendor and academic references describe CAD as an environment exposing APIs, services, and interactive tools, which aligns with selecting “All of the above.” Why Other Options Are Wrong: A/B/C: Each alone is insufficient; omitting any layer cripples the system. E: Invalid since A–C jointly describe required components. Common Pitfalls: Thinking of CAD as a monolithic app; sustainable CAD ecosystems rely on modular services and app frameworks. Final Answer: All of the above

Question 13

In robot programming, what does the “walk-through” (teach-by-guiding) method involve when creating a program for repeated motions?

Accepted Answer

Introduction / Context: Industrial robots are programmed by several methods: offline programming (simulation), teach pendant jogging, and teach-by-guiding (“walk-through”). The walk-through method is intuitive—an operator physically guides the arm through the desired path; the controller records waypoints and timing to replay the sequence automatically. Given Data / Assumptions: Robot supports gravity compensation or backdriveable joints to allow safe guiding. Controller can record joint positions, speeds, and I/O events. Application is repetitive motion such as pick-and-place or welding. Concept / Approach: Teach-by-guiding minimizes programming complexity and speeds deployment by letting domain experts demonstrate tasks directly. Once captured, the program can be refined with precise speeds, accelerations, and interlocks (e.g., gripper open/close) to ensure safety and quality. Step-by-Step Solution: Engage teach mode and enable compliant or backdriveable behavior. Physically move the robot through the desired poses and paths. Record waypoints, tool actions, and timing for each step. Exit teach mode and test the program in slow/step mode before production speeds. Verification / Alternative check: Collaborative robots popularized direct teaching; traditional robots may use force-sensing or pendant-assisted guiding, validating that physical guidance is a standard programming method in many cells. Why Other Options Are Wrong: A: Code reviews are good practice but not the definition of walk-through programming. C: Moving locations is logistics, not a programming method. D: Cannot be correct because A and C are not the method. E: Offline simulation is different from physically guiding the robot. Common Pitfalls: Failing to enable safety modes, not capturing tool I/O events, and skipping validation at reduced speed can cause collisions or poor quality. Final Answer: Physically moving or guiding the robot through all motions it will later repeat

Question 14

In feedback control terminology, what is “offset error” in steady operation of a control loop?

Accepted Answer

Introduction / Context: In closed-loop control, “offset” refers to a steady-state deviation between the desired setpoint and the measured process value. Recognizing offset is essential for diagnosing controller tuning and deciding when to introduce integral action to eliminate persistent error. Given Data / Assumptions: We consider steady operation after transients have decayed. A proportional-only controller can leave nonzero steady-state error for load or setpoint changes. Integral action is commonly used to drive steady-state error to approximately zero. Concept / Approach: Offset error = setpoint − measured value (with sign convention as defined). If the plant experiences a disturbance or requires a control effort not producible at zero error with proportional action, the loop settles with a bias. Integral action accumulates error and adjusts output until the difference is reduced, ideally removing offset. Step-by-Step Solution: Define variables: SP = setpoint, PV = process variable (measured), CO = controller output. Offset error (E_offset) = SP − PV at steady state. Recognize proportional-only control typically yields E_offset ≠ 0 under load. Adding integral action adjusts CO until PV ≈ SP, minimizing offset. Verification / Alternative check: Standard control texts illustrate that proportional-only loops on nonintegrating processes exhibit residual error after step disturbances; integral action is introduced to eliminate it, confirming the definition. Why Other Options Are Wrong: A: That describes sensor bias or calibration error, not loop offset. B: That is a mismatch between CO demand and actuator setting, not the definition of offset. D/E: Not applicable since a precise definition exists. Common Pitfalls: Confusing sensor bias with control offset; neglecting actuator saturation or deadband, which can also cause residual error even with integral action. Final Answer: The difference between the control setpoint and the actual (measured) process value

Question 15

In human–computer interaction and industrial design, the term “ergonomics” refers to which comprehensive focus area around a workstation and its use? Choose the most accurate description that emphasizes people, tasks, tools, and the surrounding envi…

Accepted Answer

Introduction / Context: Ergonomics, also called human factors engineering, studies how people interact with tools, machines, software, and spaces. The goal is to improve safety, comfort, productivity, and user satisfaction by designing workstations, controls, displays, and environments that fit human capabilities and limitations. In computing and industrial settings, ergonomics spans posture, reach, visual displays, input devices, lighting, noise, microclimate, and workflow. Given Data / Assumptions: We are selecting a definition of “ergonomics.” Ergonomics concerns both the user and the surrounding environment, not just gadget specifications or costs. The best answer should emphasize human-centered design across the workstation and its context. Concept / Approach: Proper ergonomic design matches job demands to human abilities. Typical considerations include neutral postures, adjustable chairs and desks, monitor height and distance, glare control, input device placement, cognitive load, error-proofing, and environmental conditions such as ventilation, temperature, and acoustic comfort. The field integrates anatomy, physiology, psychology, and engineering to reduce musculoskeletal strain, fatigue, and errors. Step-by-Step Solution: Identify the scope of ergonomics: people + tasks + tools + environment.Compare options: those limited to cost, involvement, or technology miss the human-system fit.Select the option that explicitly names the human aspect of both the workstation and its environment. Verification / Alternative check: Authoritative definitions highlight designing for human well-being and overall system performance. This necessarily includes anthropometrics, biomechanics, cognition, and environmental factors around the workstation. Why Other Options Are Wrong: Cost–productivity (B) is an economics view, not a definition. Operator involvement level (C) is a management attribute. Technology focus (D) centers on devices, not human fit. “None” (E) fails because a correct, comprehensive definition exists. Common Pitfalls: Confusing ergonomics with “just a good chair” or “only posture.” True ergonomics also covers reach, visibility, mental workload, lighting, noise, and workflow design. Final Answer: The human aspect of the environment around the workstation as well as the workstation itself.

Question 16

Computer graphics hardware: which of the following is primarily a graphical output device used to produce vector or large-format drawings?

Accepted Answer

Introduction / Context: Output devices convert digital information into human-readable form. In engineering and design, “graphical” often refers to devices capable of accurate vector output, wide formats, or precise line work suitable for CAD drawings, schematics, and architectural plans. Understanding each device’s core purpose helps select appropriate tools for technical documentation. Given Data / Assumptions: The goal is to identify a device designed for graphics-oriented output. Plotters historically draw continuous lines with pens; many modern large-format plotters are inkjet but remain optimized for graphics/CAD. Dot-matrix, line, and general laser printers are primarily text/bitmap devices, though they can print images. Concept / Approach: Traditional plotters (pen or modern large-format) excel at precise line drawings, vector paths, and scaled technical graphics. While laser and dot-matrix printers can render images, they rasterize content and are optimized for text or general documents rather than precision vector plotting at large scales. Line printers are strictly text-oriented high-speed devices. Step-by-Step Solution: List candidate devices and their primary design intent.Match “graphical output device” with equipment optimized for vector/large-format drawings.Choose “Plotter” as the best fit. Verification / Alternative check: CAD workflows have long used plotters for blueprints, plan sets, and schematic plots due to accuracy, scale, and line quality. Why Other Options Are Wrong: Dot-matrix (A) produces low-resolution text/graphics. Laser printer (C) is versatile but not specialized for large-format vector output. Line printer (D) targets high-volume text only. “None” (E) is invalid because a correct choice exists. Common Pitfalls: Assuming any printer that can print a picture is a “graphical device.” Precision plotting for CAD needs different mechanics and formats. Final Answer: Plotter.

Question 17

Programmable controller operation: which statement correctly describes how a PLC manages logic during runtime and what it can do?

Accepted Answer

Introduction / Context: Programmable logic controllers (PLCs) execute user programs cyclically, scanning inputs, solving logic, and updating outputs. Internally, they store the state of coils, contacts, counters, timers, and registers in memory areas that the CPU reads and writes every scan. Modern PLCs also support arithmetic and advanced instructions beyond simple relays. Given Data / Assumptions: We compare claims about PLC memory and capabilities. Latched states can be implemented in software without external hardware relays. Arithmetic and logical operations are routine in PLC instruction sets. Concept / Approach: PLC memory maps hold discrete bits (coils/contacts), timer/counter accumulators, integers, floating-point values, and more. Latching behavior is achieved using set/reset (latch/unlatch) instructions or retentive memory bits. Arithmetic instructions (ADD, SUB, MUL, DIV) and functions (compare, scale, PID) are common, enabling computation inside the controller without external devices. Step-by-Step Solution: Evaluate A: PLCs maintain logic states in RAM/NVRAM—true.Evaluate B: External latching relays are optional; internal latch instructions suffice—false as a requirement.Evaluate C: PLCs can perform math—false.Therefore select A as the only correct statement. Verification / Alternative check: Vendor manuals (Allen-Bradley, Siemens, Omron) document memory areas and arithmetic instructions, confirming internal state and computational capability. Why Other Options Are Wrong: B incorrectly mandates hardware where software latches are standard. C incorrectly denies arithmetic support. Common Pitfalls: Confusing physical relay behavior with software coils; assuming latching always requires hardware; overlooking scan-based updates that maintain memory states. Final Answer: All of the logic status is maintained in memory.

Question 18

In industrial control, one key advantage of a programmable controller (PLC) over hard-wired relay logic is that it:

Accepted Answer

Introduction / Context: Programmable controllers replaced many banks of electromechanical relays by offering software-configurable logic with solid-state reliability. Their modular I/O, diagnostics, and ease of modification improve uptime and reduce maintenance in industrial environments. Given Data / Assumptions: Electromechanical relays wear over time due to contact arcing and mechanical movement. PLCs use solid-state electronics with far fewer wear-out mechanisms. Training and documentation make PLC logic accessible; unreliability is not due to lack of moving parts. Concept / Approach: Reliability increases when you remove mechanical wear points. PLCs consolidate logic in software, provide error detection, and support rapid reconfiguration without rewiring. Mean time between failures is typically higher than relay banks, and change management becomes a software process. Step-by-Step Solution: Compare relay contacts (mechanical wear) vs. PLC solid-state switching.Assess maintainability: PLCs allow edits without rewiring, reducing downtime.Choose the option emphasizing reliable long life versus relay logic. Verification / Alternative check: Industry case studies consistently report reduced failure rates and maintenance after migrating to PLCs. Why Other Options Are Wrong: B exaggerates difficulty; ladder logic is designed to be readable. C is backward—solid-state often increases reliability. Common Pitfalls: Ignoring environmental specs; even solid-state systems need proper enclosures, grounding, and surge protection. Final Answer: Has a reliable long life compared to relay logic.

Question 19

Program execution time in control systems and software engineering: which statement is correct about what influences it and how it compares to the process being controlled?

Accepted Answer

Introduction / Context: Execution time determines how quickly control or application logic cycles, affecting responsiveness and determinism. It depends on code efficiency, language and runtime, compiler optimizations, hardware performance, and I/O latencies. Understanding these factors is crucial when coordinating software timing with mechanical or process dynamics. Given Data / Assumptions: Different languages and runtimes (compiled C, interpreted scripting, ladder) incur different overheads. Real-time needs usually require the software to be fast enough relative to the process being controlled. Code and configuration can be optimized or refactored, so timing is not immutable after first write. Concept / Approach: Execution time per cycle (or per function) is influenced by instruction count, runtime services (garbage collection, VM), and I/O waits. Faster languages/compilers and better algorithms reduce timing. In control, scan time should be less than the smallest relevant process time constant to avoid aliasing and sluggish response. Step-by-Step Solution: Evaluate A: software “must be slower” than the fastest mechanical operation is incorrect; it generally must be fast enough to react within process deadlines.Evaluate B: language and implementation affect execution time—true.Evaluate C: timing can change via optimization, compiler flags, hardware upgrades, or algorithm changes—so false.Therefore, choose B. Verification / Alternative check: Benchmarking the same algorithm in C versus an interpreted language yields different throughput; PLC scan times vary by instruction set and hardware. Why Other Options Are Wrong: A reverses the desirable relationship. C ignores the possibility of optimization and refactoring. D cannot hold if A and C are false. Common Pitfalls: Relying on nominal scan times without verifying worst-case path or I/O latency; ignoring garbage collection pauses in soft real-time systems. Final Answer: Will vary depending on the language used.

Question 20

Display systems: the technique of skipping every other line on the first pass and drawing the skipped lines on a second pass is called:

Accepted Answer

Introduction / Context: Video displays can update images in different patterns. Legacy television standards improved perceived flicker and bandwidth use by drawing alternate lines in successive passes, a method known as interlacing. Understanding how interlacing differs from raster-scan and vector methods clarifies terminology in graphics and display engineering. Given Data / Assumptions: The method described draws odd lines first, then even lines (or vice versa). Interlacing targets reduced flicker and bandwidth at a given frame rate. Other techniques (vector/refresh-vector, stroke) draw lines as directed paths, not in alternating raster fields. Concept / Approach: Interlaced scanning divides each full frame into two fields. Field 1 contains every other line, and Field 2 fills in the remainder. By refreshing fields more often than full frames, the eye perceives smoother motion at lower data rates. Raster-scan draws every line sequentially each frame. Vector (stroke) displays steer the beam along line segments rather than sweeping rows of pixels. Step-by-Step Solution: Match “skip lines on first pass, draw them on second” with interlacing.Eliminate vector/refresh-vector and stroke writing, which do not use alternating fields.Confirm the term: Interlacing. Verification / Alternative check: Standards such as 1080i exemplify interlaced video using two fields to complete a frame. Why Other Options Are Wrong: Refresh-vector (B) and stroke (D) are vector-based methods. Raster-scan (C) draws consecutive lines without skipping every other line. Common Pitfalls: Confusing interlacing with “interpolation.” Interlacing is a scan pattern, not a resampling algorithm. Final Answer: Interlacing.

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