Question

Electrical Engineering Quiz Review 04 Topic: Optimization Techniques 8.(a). Consider a PPM signal band limited to 10 KHz, Composed of equal-amplitude pulses of 1 uus width whose position relative to the time of sampling may be delayed from 2 us to 6 us. What is the maximum number of such signals that can be time-division multiplexed? (5pts) (b). What are the methods of inventory control? (2 pts) (c). Annual demand for an item is 5400 units. Ordering cost is Rs 600 per order. Inventory carrying cost is 30% of the purchase price per unit per year. The price breaks are as shown below, Price Quantity OsQs 2400 2401 SQ, 53000 3001 sa 10 (i) (ii) Find the EOQ. Find the optimal order size. (5pts)

Answer 1

ANS: a. Given that, For a PPM signal, Maximum frequency, fm = 10KHz width of the pulses, t= 1 US The minimum positional shift of the pulsé = quis The maximum positional shift of the pulse - Gus The maximum number of signal which can be time division multiplexed = ? The maximum number of signal can be time. division multiplexed when it satisfies the sampling theorem ive, Nyquist rate. The sampling rate is given as, fs = 2 fm - fs = 2 x 10 KHz - 20 k samples Is. The sampling period is given as, Ts = 1 = 30k Cs Scanned with - 5 X 10-5 CamScanner 20

PPM signal, it = 5x10-6 = 50 us According to the given positional shift Of is plotted as shown in figure. Mayment shift Minimum - t (us) sampling instant Time slot required for transmission of one signal 1 = 5 us that can be time -division The maximum number of signals multiplexed can be obtained as, Maximum number of signals, Nm = sampling period 50 US Time required for transmission of one signal - 5 Us A Nm = 10 signals ? Scanned with CamScanner

following Ane: b. The are the different methods of inventory control, i ABC classification It is also known as 'Always Better Control. It takes into consideration the value of consumption of items concerned and it has nothing to do with the unit value of the item. It is used to control raw materials, components and work in progress. (2) HML classification This method is similar to ABC classification. But Pn this case instead of consumption value of items, only the unit value. Of the item is considered. As the name implise the materials are classified according to their unit value as High Medium and Low. Hence the gtems are listed according to the descending order of unit values and management decides the cutoff points . st is used mainly to control purchases. (3) XYZ dassification while ABC classification has the value of as the basis xyz classification has the consumption Scanned with CamScanner

Value of Pnventory available as a basis on a particular date in stores. The study is taken up every year in the form of scheduled interval review of the inventories and their uses. 'x' items are those items whose stock values are high, 'y' items are of medium value while z' items are house items whose stock values are low. A, VED classi fication VED classification is applicable to a large extent in spare parts management stocking of Spares has got a different strategy than stocking yow materials. while the consumplíon of row materials depends directly on the market demand, spoare parts demand depends cypon the performance of plant and machinery. So, spares are classified as Vital, Essential and Desirable in order to determine the stocking levels of spare parts depending on the criticality of the item. -5, FSN classification ESN classification is used to control obsolescences and it is also applicable to spare parts management, on this basis the consumption patteren of the spares items are ascertained. The spores are classified as fast moving, i slow moving and non-mos Slog canned with CamScanner IS

6 SDE classification SDE classification is used for lead time analysis and purchasing strategies. So it looks for the problems faced in procurement and the classification is done as scarce, Difficult and Easy to obtain the materials. 17 GOLF classification This classification is made taking into consideration the source of supply and it is used to formulate procurement strategies classification qs done as Government, ordinary, local and foreign sources. 8, sos classification This classification is used for formulation of procurement and holding strategies for seasonal items like agricultural products and the classification is based on nature of supplies lie., Seasonal and off - Seasonalo Scanned with CamScanner

soli- c. Given, Annual demand, D = 5,400 units ordeving cost, Co = 3600 cornying cost, I = 0.30. unit cost : C, = 12, C2= 10, C3-8. Gs for highest dis count at C = C = 8. (coa) a; - усіх 2x 5400 x 600 8X0:30 = 1643.17 = 1643 units. .: as <b> (3,000), o te is not a = 2DCo feasible V C2 XI 2x 5400 X 600 10X0:30 V 1,469.69 = 1,470 units az is not feasible I äg<b, (2,401), ai. 2000 VCI Scanned with CamScanner

2x5400 x 600 20:30 = 1341.64 = 1342 units TC (@) - TC (1.342) DXC + a1" x Cn+DG I a=Ixc. 1 - 5400 x 600 + 1342 x (0.30x12 ) + 5400 x12 1342 2414 + 2416 + 64,800 = 5 69,630- TC (2,401) - D X6 + bx x C +DC, - 5400 x 600 + 2401 * (0:30 X10 ) +5400 X10 2401 - 6 349.44 + 3601.5 + 54,000 = $ 58,950.94 $ 58,951 TC (3,000) = I x Co + b2 x C + DC3 - 5400 600 + 30 0:30*8) +5,400 n8. 3001 = 1079.64 + 3601.2 + 43,200 CS Scanned with CamScanner = 47.880.84

Ž 47,881 a TC (3,001) is the lowest of all Tc's c) EoQ (@) = 1,470 Units til Optimal order size is b2= 3,000 units. Scanned with CamScanner