Industry 4.0 · Quiz 1 · Jan 2023

**1. Identify the course’s advanced-transport example:** Hyperloop proposes high-speed movement of pods through low-pressure tubes, combining advanced propulsion, controls and infrastructure. **2. Match the offered choices:** Within this course’s historical examples, Hyperloop is the intended Industry 4.0 transport concept. An internal-combustion engine and an electric drivetrain alone do not define digitally connected transport. **Answer: C — Hyperloop.** **Convention note:** This is a course-specific example, not a universal technical definition of Industry 4.0. Connected, data-driven and autonomous systems can also be Industry 4.0 transport applications; an electric vehicle can incorporate them. A: **Incorrect:** The internal-combustion engine is an earlier industrial transport technology. B: **Incorrect:** Electric propulsion alone is not the course’s intended marker for Industry 4.0. C: **Correct:** Hyperloop is the advanced transport concept intended in this question.

**1. Identify the second industrial revolution:** Widespread electric power supported electrically driven machinery, assembly lines and large-scale mass production. **2. Distinguish the other eras:** Steam-powered mechanization characterizes the first revolution. Electronics, computers and programmable automation characterize the third; connected cyber-physical systems characterize the fourth. **Answer: A — Electric Power.** A: **Correct:** Electric power is the defining energy development associated with the second industrial revolution. B: **Incorrect:** Mechanization through water and steam power is associated with the first revolution. C: **Incorrect:** Computer-based automation belongs mainly to the third revolution. D: **Incorrect:** Industrial robotics is associated with later automation rather than the defining second-era transition.

**1. Find the bottleneck:** Each unit must pass through the required stations. The station with the longest effective processing time cannot supply units as quickly as the others. **2. Convert its time into a rate:** For a simple serial line without parallel capacity, \(\text{maximum rate}=1/\max_i t_i\). Faster stations cannot remove that bottleneck merely by working faster. **Answer: A — Slowest station.** A: **Correct:** Its effective capacity limits the serial line’s sustainable throughput. B: **Incorrect:** A fast station can finish early but must wait for the bottleneck. C: **Incorrect:** An idle station is not the normal capacity-setting rule. D: **Incorrect:** The bottleneck station is already identified by A.

**1. Identify a product layout:** Workstations follow the fixed processing sequence for a standardized product. **2. Explain the inventory benefit:** A balanced, repetitive flow reduces movement and waiting between operations, helping keep work in process small. It does not guarantee low investment or high utilization under every demand level. **Answer: A — Small in-process inventory.** A: **Correct:** Continuous, coordinated flow can reduce intermediate queues and work in process. B: **Incorrect:** High variety generally favors a flexible process layout rather than a dedicated line. C: **Incorrect:** Utilization depends on demand and line balance; it is not guaranteed for all dedicated machines. D: **Incorrect:** Dedicated lines can require substantial initial investment.

**1. Convert daily operating time:** Two 8-hour shifts provide \(T=2(8)(3600)=57{,}600\) seconds per day. **2. Divide time by required output:** \[C=\frac{T}{Q}=\frac{57{,}600}{30{,}000}=1.92\text{ seconds/unit}.\] **3. Apply the requested rounding:** The required line cycle time is 1.9 seconds to one decimal. This is the permitted interval between completed bulbs, not the sum of all task times. **Answer: 1.9.**

**1. Define the fixed-position idea:** The focal product or service recipient stays in place while the people and resources needed to perform work come to it. **2. Apply the service example:** In a fine-dine restaurant, the seated customer stays at the table while staff deliver food and service. A shared Google document is the course’s virtual analogy: collaborators bring their contributions to one shared artifact. **3. Distinguish moving-customer and flow-line arrangements:** Buffet guests move between food stations, bank customers move through service points, and automobiles progress along an assembly line. **Answer: A, C — A and C.** **Convention note:** A shared Google document is a conceptual analogy, not a physical factory-layout classification. For a service layout, the answer depends on identifying the customer as the focal recipient of work. A: **Correct:** The customer remains seated and service resources come to the table, matching the intended service analogy. B: **Incorrect:** Buffet guests move to the serving stations instead of receiving all service at a fixed table. C: **Correct:** In the intended analogy, the document is the shared focal artifact and contributors bring their work to it. D: **Incorrect:** The product moves through sequential workstations, which is a product layout. E: **Incorrect:** A branch typically groups service functions into counters or departments; it is not the stationary-customer service example intended here.

**1. Identify the distance objective:** The usual Euclidean location problem minimizes weighted straight-line distances: \[\min_{x,y}\sum_i w_i\sqrt{(x-x_i)^2+(y-y_i)^2}.\] Its solution is a weighted geometric median. **2. Distinguish the center of gravity:** A weighted coordinate mean minimizes the sum of squared distances, a different objective. It can coincide with a geometric median in symmetric cases, but equality is not guaranteed. **3. Interpret the standard result:** A nondegenerate Euclidean problem generally identifies a particular optimal point, rather than the median interval/rectangle possible with rectilinear distance. **Answer: B, C — B and C — generally a point, not generally the center of gravity.** **Convention note:** The question uses “rarely” informally. Coincidence depends on the data, and special collinear configurations can have an interval of minimizers. The answer assumes the usual unsquared Euclidean objective and a nondegenerate instance. A: **Incorrect:** A region is not the usual nondegenerate Euclidean-location result, though special collinear cases can have multiple optimal points. B: **Correct:** Read as “does not generally coincide”: a geometric median is not generally the weighted coordinate mean. C: **Correct:** A point is the standard nondegenerate result; this is not a uniqueness theorem for every possible dataset. D: **Incorrect:** If the malformed phrase means “none,” it is false because symmetry can produce coincidence; if it means “most,” that is not generally guaranteed.

**1. Read times and dependencies:** A1–A10 take 9,5,18,10,6,8,16,19,5,13 minutes. A6 needs A1 and A3; A7 needs A1 and A4; A8 needs A3 and A5; A9 needs A2; A10 needs A8 and A9. **2. Test the station loads for A:** The proposed six groups (A3), (A1,A4), (A2,A5,A6), (A8), (A10,A9), (A7) take 18,19,19,19,18,16 minutes. Every load is at most the required 20-minute cycle. **3. Check precedence within and between groups:** All prerequisites are available in earlier groups or can be completed earlier within the same group. In the fifth group, perform A9 before A10 even though the group is written (A10,A9). Group membership need not prescribe the internal execution order. **Answer: A — (A3)–(A1,A4)–(A2,A5,A6)–(A8)–(A10,A9)–(A7).** **Convention note:** Activities listed within one workstation are interpreted as a group that can be internally sequenced. If their printed order were compulsory, A10 before A9 would violate precedence; the keyed answer relies on the grouping interpretation. A: **Correct:** Every activity appears once, each load is at most 20, and ordering A9 before A10 within their station satisfies precedence. B: **Incorrect:** The first station combines A3 and A2, taking 18+5=23 minutes and exceeding the 20-minute cycle. C: **Incorrect:** Its first station includes A6 before A1 and A3 have been completed in later stations. D: **Incorrect:** It omits A5 and A6, and A1+A4+A2 takes 9+10+5=24 minutes, exceeding the cycle.

**1. Calculate total task work:** \[W=9+5+18+10+6+8+16+19+5+13=109\text{ minutes/unit}.\] **2. Use the specified production pace:** The feasible grouping (A3), (A1,A4), (A2,A5,A6), (A8), (A9,A10), (A7) uses six stations. At the required cycle of 20 minutes, each unit has 6×20=120 station-minutes available. **3. Calculate the unused fraction:** \[BD=\frac{NC-W}{NC}\times100=\frac{120-109}{120}\times100=9.17\%.\] Enter 9.17 without the percent sign. **Answer: 9.17.** **Convention note:** This uses the target cycle of 20 minutes stated in the preceding question. The largest station load is actually 19 minutes; operating at that faster cycle would instead give 100×(114−109)/114=4.39% delay.