Questions
You're helping some security analysts monitor a collection of networked computers,
You're helping some security analysts monitor a collection of networked computers, tracking the spread of an online virus. There are n computers in the system. labeled \(01, C 2, \ldots, \mathrm{Cn}\), and as input you're given a collection of trace data indicating the times at which pairs of computers communicated. Thus the data is a sequence of ordered triples \((\mathrm{Cl}, C j, t k)\), such a triple indicates that \(C /\) and \(C j\) exchanged bits at time \(t k\). There are \(m\) triples total
We'll assume that the triples are presented to you in sorted order of time For purposes of simplicity, we'll assume that each pair of computers communicates at most once during the interval you're observing.
The security analysts you're working with would like to be able to answer questions of the following form: If the virus was inserted into computer Ca at time \(x\), could it possibly have infected computer \(\mathrm{Cb}\) by time \(y\) ? The mechanics of infection are simple: if an infected computer Ci communicates with an uninfected computer \(\mathrm{Cj}\) at time tk (in other words, if one of the triples \((\mathrm{Ci}, \mathrm{Cj}, t k)\) or \((\mathrm{C} j, \mathrm{Cl}, t k)\) appears in the trace data), then computer \(C j\) becomes infected as well, starting at time tk. Infection can thus spread from one machine to another across a sequence of communications, provided that no step in this sequence involves a move backward in time. Thus, for example, if \(C i\) is infected by time \(t k\), and the trace data contains triples \((C i, C j\) \(t k)\) and \((C j, C q, t r)\), where \(t k \leq t r\), then Cq will become infected via \(C\). (Note that it is okay for \(t k\) to be equal to tr ; this would mean that Cj had open connections to both \(C\) i and \(C q\) at the same time, and so a virus could move from \(\mathrm{C}\) i to \(\mathrm{Cq}\).)
For example, suppose \(n=4\), the trace data consists of the triples
\((\mathrm{C} 1, \mathrm{C} 2,4),(\mathrm{C} 2, \mathrm{C} 4,8),(\mathrm{C} 3, \mathrm{C} 4,8),(\mathrm{C} 1, \mathrm{C} 4,12)\)
and the virus was inserted into computer \(\mathrm{C} 1\) at time 2 . Then \(\mathrm{C} 3\) would be infected at time 8 by a sequence of three steps: first \(C 2\) becomes infected at time 4 , then \(C 4\) gets the virus from \(C 2\) at time 8 , and then \(\mathrm{C} 3\) gets the virus from \(\mathrm{C} 4\) at time 8 . On the other hand, if the trace data were
\((C 2, C 3,8),(C 1, C 4,12),(C 1, C 2,14)\)
and again the virus was inserted into computer \(\mathrm{C} 1\) at time 2 , then \(\mathrm{C} 3\) would not become infected during the period of observation although \(C 2\) becomes infected at time 14 , we see that C3 only communicates with \(C 2\) before \(C 2\) was infected There is no sequence of communications moving forward in time by which the virus could get from \(\mathrm{C}1\) to \(\mathrm{C} 3\) in this second example.
Design an algorithm that answers questions of this type given a collection of trace data, the aigorithm should decide whether a virus introduced at computer Ca at time x could have aeter comouter Cb by time \(y\). The algorithm should run in time \(O(m+n)\)
In: Other
Which of the following is true of Software as a Service? Select one: a. It requires...
Which of the following is true of Software as a Service?
Select one:
a. It requires an organization to maintain and develop the software.
b. It requires the installation of specialized interfaces at the client end.
c. It involves fixed monthly and yearly costs for the services.
d. It is not scalable in response to large increases in demand.
e. It allows clients to access services on an as-needed basis.
In: Other
Variations in the resistivity of blood can give valuable clues to changes in the blood's viscosity and other properties.
Variations in the resistivity of blood can give valuable clues to changes in the blood's viscosity and other properties. The resistivity is measured by applying a small potential difference and measuring the current. Suppose a medical device attaches electrodes into a 1.5-mm-diameter vein at two points 5.0 apart.
What is the blood resistivity if a 8.9 V potential difference causes a 240 mu A current through the blood in the vein (in omega*m)?
In: Other
A firm uses the pure chase strategy of aggregate planning. It produced 1000 units in the...
- add 100 units to inventory in the next period
- add 200 units to inventory in the next period
- hire workers to match the 100-unit difference
- lay off workers to match the 200-unit difference
- implement a lower price point to increase demand
In: Other
3. Which of the following is most associated with managerial accounting? a. must follow GAAP...
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3. Which of the following is most associated with managerial accounting?
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4. Which of the following is most associated with financial accounting?
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5. Which of the following statements is false?
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6. In most business organizations, the chief management accountant is called the
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In: Other
The business analyst for Video Sales, Inc. wants to forecast yearly demand for DVD decoders based...
The business analyst for Video Sales, Inc. wants to forecast yearly demand for DVD decoders based on the following historical data:
| Year | Demand |
|---|---|
| 5 years ago | 900 |
| 4 years ago | 700 |
| 3 years ago | 600 |
| 2 years ago | 500 |
| Last year | 300 |
What is the forecast for this year using a three-year simple moving average?
What is the forecast for last year using simple exponential smoothing with smoothing constant alpha = 0.4, if the forecast for two years ago was 750?
What is the forecast for this year using simple exponential smoothing with smoothing constant alpha = 0.4, if the forecast for two years ago was 750?
In: Other
Christopher's Cranks uses a machine that can produce 100 cranks per hour. The firm operates 12...
Christopher's Cranks uses a machine that can produce 100 cranks per hour. The firm operates 12 hours per day, five days per week. Due to regularly scheduled preventive maintenance, the firm expects the machine to be running during approximately 95% of the available time. Based on experience with other products, the firm expects to achieve an efficiency level for the cranks of 85%. What is the expected weekly output of cranks for this company?
In: Other
24. Four employees at a fast-food restaurant each perform one of the four activities in serving...
24. Four employees at a fast-food restaurant each perform one of the four activities in serving a customer: greet customer, take order, process order, and deliver order. The processing time for each activity is given as follows:
|
Activity |
Processing time per customer |
|
Greet customer |
2 seconds |
|
Take order |
30 seconds |
|
Process order |
60 seconds |
|
Deliver order |
5 seconds |
Assume demand is unlimited. If each employee is paid $7.50 per hour,
What is the cost of direct labor associated with serving one customer (show calculations)?
What is the labor content associated with serving one customer (show calculations)?
What is the average labor utilization (show calculations)?
What is the total idle time (show calculations)?
25. Given the following data at the drive-through of a bank,
|
Customer |
Arrival Time |
Service Time (minutes) |
|
1 |
8:06 |
5 |
|
2 |
8:10 |
10 |
|
3 |
8:15 |
7 |
|
4 |
8:36 |
2 |
What is the processing time of the second customer?
What is the average processing time from 8:06 to 8:36?
What is the average interarrival time from 8:06 to 8:36?
Is there, on average, enough capacity to serve all customers (show calculations)?
In: Other
The Carbondale Hospital is considering the purchase of ambulance. The TheXarbondale Hospital is considering the purchase...
The Carbondale Hospital is considering the purchase of ambulance. The TheXarbondale Hospital is considering the purchase of ambulance. The decision will rest partly on the anticipated mileage" be driven next year. The miles driven during the past 5
years are as follows:
|
Year |
Mileage |
|
1 |
3000 |
|
2 |
4000 |
|
3 |
3400 |
|
4 |
3800 |
|
5 |
3700 |
a) Forecast the mileage for next year using a 2-year moving average.
b) Find the MAD based on the 2-year moving average forecast in part (a), (Hint: You will have only 3 years of matched data.)
c) Use a weighted 2-year moving average with weights of .4 and .6 to forecast next year's mileage. (The weight of .6 is for the most recent year.) What MAD results from using this approach to forecasting? (Hint: You will have only 3 years of matched data.)
d) Compute the forecast for year 6 using exponential smoothing, an initial forecast for year 1 of 3,000 miles, and a = .5.
*****PLEASE SHOW WORK
In: Other
JAVA You will be given a grocery list, filed by a sequence of items that have already been purchased.
Instructions
You will be given a grocery list, filed by a sequence of items that have already been purchased. You are going to determine which items remain on the the list and output them so that you know what to buy.
You will be give an integer n that describes how many items are on the original grocery list. Following that, you will be given an array of n grocery list items (strings) that you need to buy. After your grocery list is complete, you will receive a list of items that had already been purchased. For each of these items, if it matches any item on your grocery list, you can mark that item as purchased. You will know that you are at the end of the list of items already purchased when you receive the string "DONE".
At that point, you will output a list of items left to buy (each item on its own line).
Write the body of the program called PoD. java to the left.
Input
The program reads in the following:
an integer (n) defining the length of the original grocery list
in strings that make up the grocery list a list of items that had already been purchased (strings)
in strings that make up the grocery list a list of items that had already been purchased (strings)
the string "DONE", marking the end of all required input
Processing
Determine which items on the grocery list have already been purchased.
Output
Output the items from the grocery list that remain to be purchased (i.e. all items from the original n grocery items that were not
included in the list of items already purchased). Each grocery item must be printed on its own line. The text must be
purchased). Each grocery item must be printed on its own line. The text must be terminated by a new-line character.
In: Other
Which of the following statements about takt time and cycle time is true? A. Takt time...
Which of the following statements about takt time and cycle time is true?
A. Takt time only depends on demand, not capacity. Cycle time does depend on capacity.
B. Takt time only depends on capacity, not demand. Cycle time does depend on demand.
C. Takt time and cycle time only depend on capacity.
D. Takt time and cycle time only depend on demand.
In: Other
Andrew Thomas, a sandwich vendor at Hard Rock Caf's annual Rockfest created a table of conditional...
Andrew Thomas, a sandwich vendor at Hard Rock Cafe's annual Rockfest created a table of conditional values for the various alternatives (stocking decision) and states of nature (size of crowd):
Alternatives | States of Nature Big Average Small | ||
Large Stock | $22,000 | $12,000 | -$2,000 |
Average Stock | $14,000 | $10,000 | $6,000 |
Small Stock | $9,000 | $8,000 | $4,000 |
The probabilities associated with the states of nature are 0.3 for a big demand, 0.5 for an average demand, and 0.2 for a small demand.
1. Determine the alternative that provides Andrew the greatest Expected Monetary Value. What is this EMV?
2. What is the expected value under certainty?
3. Compute the expected value of perfect information, (EVPI)
4. Determine the appropriate alternative under uncertainty using Maximin. Provide support for your answer.
In: Other
The demand for subassembly S is 100 units in week 7. Each unit of S requires...
The demand for subassembly S is 100 units in week 7. Each unit of S requires 1 unit of T and 2 units of U. Each unit of T requires 1 unit of V, 2 units of W, and 1 unit of X. Finally, each unit of U requires 2 units of Y and 3 units of Z. One firm manufactures all items. It takes 2 weeks to make S, 1 week to make T, 2 weeks to make U, 2 weeks to make V, 3 weeks to make W, 1 week to make X, 2 weeks to make Y, and 1 week to make Z.
On-hand inventory information is given as below:
|
ITEM |
ON-HAND INVENTORY |
ITEM |
ON-HAND INVENTORY |
|
S |
20 |
W |
30 |
|
T |
20 |
X |
25 |
|
U |
40 |
Y |
240 |
|
V |
30 |
Z |
40 |
- Construct a product structure. Identify all levels, parents, and components.
- Construct a net material requirements plan (Hint. Use on-hand inventory table for this question)
In: Other
Consider the baggage check-in of a small airline. Check-in data indicate that from 9 a.m. to...
Consider the baggage check-in of a small airline. Check-in data indicate that from 9 a.m. to 10 a.m., 255 passengers checked in. Moreover, based on counting the number of passengers waiting in line, airport management found that the average number of passengers waiting for check-in was 35. How long did the average passenger have to wait in line?
In: Other
What is the capacity of the milling machine (in tables per day) if the batch size is 10?
C & A Furniture uses a four-step process to make its famous wood table:
Process - Processing Time (minutes)
Milling-table top-10 minutes
Milling-table stand - 5 minutes
Assembly - 15 minutes
Finishing - 20 minutes
The milling machine requires a setup time of 30 minutes to make table tops and a changeover time of 30 minutes to make table stands.C\&A works an 8 -hour day: What is the capacity of the milling machine (in tables per day) if the batch size is 10?
In: Other