Grealish - Aston Villa Rekordgehalt Fur Grealish

Timing Diagram

Unified Modeling Language

Janis Osis , Uldis Donins , in Topological UML Modeling, 2017

1.two.two.7 Timing Diagram

Timing diagram is used to show interactions when a primary purpose of the diagram is to reason well-nigh fourth dimension; information technology focuses on conditions changing inside and amidst lifelines along a linear time centrality. Timing diagram is a special grade of a sequence diagram. The most notable graphical divergence between timing diagram and sequence diagram is that time dimension in timing diagram is horizontal and the time is increasing from left to the right and the lifelines are shown in divide compartments arranged vertically. The timing diagram is available since UML version 2.0 and includes elements such as message, lifeline, timeline, and object or role.

Read full chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9780128054765000010

Fundamentals

John Crowe , Barrie Hayes-Gill , in Introduction to Digital Electronics, 1998

Example ane.21

Given the timing diagram in Fig. 1.12, write out the truth table for the circuit responsible for information technology, the Boolean equation describing its operation and draw the bodily circuit.

Fig. 1.12. Timing diagram for Example 1.21

Solution

From the timing diagram we tin can determine the values of the output, Y, for given input values of A, B and C. These values can be used to produce the truth table in Fig. 1.xiii together with the circuit.

Fig. 1.thirteen. Truth table and circuit produced from the timing diagram in Fig. one.12 (Case 1.21)

So, from the truth table we can see that the output is 1 if either A = 1, irrespective of the values of B and C (i.e. the bottom four rows of the truth table), OR if ((B = 0) AND (C = 0)). And so we can deduce that $Y=A+\left(\overline{B}\cdot \overline{C}\right)$ . (We will look at more rigorous means of obtaining such data in after capacity.) Notation that the truth table has been written in binary ordered fashion, equally is usual, even though the values are not read off from the waveform in this lodge.

Read full chapter

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/B9780340645703500034

Computing Platforms

Marilyn Wolf , in Computers as Components (3rd Edition), 2012

Draw a timing diagram with the following signals (where [ t _one,t ₂] is the time interval starting at t ₁ and ending at t ₂):

a.

signal A is stable [0,10], irresolute [10,15], stable [15,xxx]

b.

signal B is i [0,5], falling [5,7], 0 [7,20], changing [twenty,xxx]

c.

signal C is changing [0,10], 0 [ten,fifteen], rising [15,18], 1 [18,25], changing [25,30]

Read total chapter

URL:

https://world wide web.sciencedirect.com/science/article/pii/B9780123884367000040

Enforcing Modularity with Clients and Services

Jerome H. Saltzer , M. Frans Kaashoek , in Principles of Computer System Pattern, 2009

iv.1.ii Customer/Service Arrangement

One skillful way to enforce modularity is to limit the interactions among modules to explicit messages. It is convenient to impose some structure on this organization by identifying participants in a advice equally clients or services.

Figure 4.three shows a common interaction between client and service. The customer is the module that initiates a request: it builds a message containing all the data necessary for the service to carry out its job and sends it to a service. The service is the module that responds: it extracts the arguments from the asking bulletin, executes the requested operations, builds a response message, sends the response message back to the client, and waits for the next request. The client extracts the results from the response message. For convenience, the bulletin from the client to the service is called the asking, and the message is chosen the response or reply.

Figure 4.3. Communication between customer and service.

Effigy iv.3 shows one common style in which a client and a service interact: a request is always followed by a response. Since a client and a service can interact using many other sequences of letters, designers often correspond the interactions using message timing diagrams (run across Sidebar 4.2). Figure iv.3 is an example of a elementary timing diagram.

Sidebar 4.2

Representation

Timing Diagrams

A timing diagram is a user-friendly representation of the interaction between modules. When the organization is organized in a client/service style, this presentation is peculiarly convenient, considering the interactions between modules are express to messages. In a timing diagram, the lifetime of a module is represented by a vertical line, with time increasing down the vertical centrality. The following example illustrates the use of a timing diagram for a sewage pumping system. The characterization at the top of a timeline names the module (pump controller, sensor service, and pump service). The physical separation between modules is represented horizontally. Since it takes time for a bulletin to become from i signal to another, a message going from the pump controller to the pump service is represented by an arrow that slopes downward to the correct.

The modules perform actions, and send and receive letters. The labels side by side to the fourth dimension bespeak deportment taken past the module at a certain time. Modules can have actions at the same fourth dimension, for instance, if they are running on different processors.

The arrows indicate messages. The start of the arrow indicates the time the message is sent by the sending module, and the indicate of an pointer indicates the time the message is received at the destination module. The content of a message is described by the label associated with the arrow. In some examples, letters can be reordered (arrows cross) or lost (arrows terminate midflight before reaching a module).

The simple timing diagram shown in this sidebar describes the interaction betwixt a pump controller and ii services: a sensor service and a pump service. There is a request containing the message "measure tank level" from the client to the sensor service, and a response reports the level read by the sensor. There is a third bulletin, "start pump", which the customer sends to the pump service when the level is too loftier. The second bulletin has no response. The diagram shows 3 actions: reading the sensor, deciding whether the pump must exist started, and starting the pump. Figure 7.vii [on-line] shows a timing diagram with a lost bulletin, and Effigy 7.9 [on-line] shows one with a delayed message.

Conceptually, the customer/service model runs client and services on separate computers, connected by a wire. This implementation also allows client and service to exist separated geographically (which can be good because it reduces the hazard that both fail attributable to a common fault such as a power outage) and restricts all interactions to well-divers messages sent beyond a wire.

The disadvantage of this implementation is that it requires i calculator per module, which may be plush in equipment. It may besides take a operation cost because information technology may accept a substantial amount of time to send a message from i computer to another, in item if the computers are far away geographically. In some cases these disadvantages are unimportant; for cases in which it does thing, Chapter 5 volition explain how to implement the client/service model within a single computer using an operating system. For the residue of this chapter we will assume that the client and the service each accept their ain reckoner.

To reach loftier availability or handle big workloads, a designer may choose to implement a service using multiple computers. For instance, a file service might use several computers to achieve a high degree of fault tolerance; if i calculator fails, another one tin can take over its office. An example of a service running on a single computer is chosen a server.

To make the customer/service model more than concrete, let's rearrange our measure out program into a simple client/service organization (see Figure iv.iv). To get a time from the service, the customer procedure builds a request message that names the service and specifies the requested operation and arguments (lines two and half-dozen). The requested operation and arguments must exist converted to a representation that is suitable for manual. For example, the customer reckoner may be a big-endian calculator (see Sidebar 4.iii), while the service reckoner may be a footling-endian reckoner. Thus, the customer must convert arguments into a canonical representation so that the service can interpret the arguments.

Figure four.4. Instance client/service application: time service.

Sidebar 4.3

Representation

Big-Endian or Footling-Endian?

Ii common conventions exist for numbering bits within a byte, bytes within a word, words within a folio, and the similar. Ane convention is called large-endian, and the other niggling-endian *. In big-endian the most pregnant bit, byte, or word is numbered 0, and the significance of bits decreases equally the address of the chip increases:

Words	0				1
Bytes	0	1	…	seven	0	1	…	7
Bits	20iii22…			…263	ii0212ii…			…263

In big-endian the hex number ABCD_hex would be stored in retentiveness, then that if you read from memory in increasing retention address club, you would meet A-B-C-D. The string "john" would be stored in memory as john.

In niggling-endian, the other convention, the least significant bit, byte, or word is numbered 0, and the significance of bits increases as the address of the bit increases:

Words	n				n − i
Bytes	seven	…	1	0	7	…	1	0
Bits	two63…			…222120	ii63…			…222ane20

In little-endian, the hex number ABCD_hex would be stored in memory, so that if you read from retentivity in increasing memory address order, yous see D-C-B-A. The string "john" would still be stored in memory as john. Thus, code that extracts bytes from character strings transports between architectures, but code that extracts bytes from integers does not send.

Some processors, such as the Intel x86 family, use the trivial-endian convention, just others, such as the IBM PowerPC family, utilise the large-endian convention. As Danny Cohen pointed out in a ofttimes cited article "On holy wars and a plea for peace" [Suggestions for Farther Reading 7.2.4], information technology doesn't matter which convention a designer uses as long as it is the same one when communicating between two processors. The processors must agree on the convention for numbering the bits sent over the wire (that is, send the most significant bit offset or send the least significant chip beginning). Thus, if the communication standard is big-endian (as it is in the Net protocols), then a client running on a little-endian processor must marshal information in large-endian society. This book uses the big-endian convention.

This volume also follows the convention that fleck numbers start with zero. This choice is contained of the big-endian convention; we could have chosen to use 1 instead, as some processors do.

This conversion is called marshaling. We use the notation {a, b} to denote a marshaled message that contains the fields a and b. Marshaling typically involves converting an object into an assortment of bytes with enough annotation then that the unmarshal procedure can convert it dorsum into a language object. In this example, we prove the align and unmarshal operations explicitly (eastward.yard., the process calls starting with convert), but in many future examples these operations will exist implicit to avoid clutter.

After amalgam the request, the client sends it (two and 6), waits for a response (line 3 and 7), and unmarshals the time (4 and 8).

The service procedure waits for a request (line 12) and unmarshals the request (lines xiii and 14). So, it checks the request (line 15), processes information technology (lines 16 through 19), and sends back a marshaled response (line 20).

The customer/service arrangement not but separates functions (brainchild), it also enforces that separation (enforced modularity). Compared to modularity using procedure calls, the client/service organisation has the post-obit advantages:

■

The client and service don't rely on shared state other than the messages. Therefore, errors can propagate from the client to the service, and vice versa, in simply one way. If the services (as in line fifteen) and the clients cheque the validity of the request and response messages, and then they can control the ways in which errors propagate. Since the client and service don't rely on global, shared information structures such equally a stack, a failure in the client cannot directly corrupt data in the service, and vice versa.

■

The transaction between a client and a service is an arm'southward-length transaction. Many errors cannot propagate from one to the other. For example, the client does not have to trust the service to return to the appropriate render accost, as it does using process calls. As some other example, arguments and results are marshaled and unmarshaled, allowing the customer and service to check them.

■

The customer tin can protect itself even against a service that fails to render because the customer tin put an upper limit on the time information technology waits for a response. Equally a result, if the service gets into an infinite loop, or fails and forgets most the request, the client can detect that something has gone wrong and undertake some recovery procedure, such as trying a different service. On the other hand, setting timers can create new problems because it can be hard to predict how long a wait is reasonable. The problem of setting timers for service requests is discussed in detail in Section vii.5.two [on-line]. In our example, the client isn't defensive against service errors; providing these defenses volition make the plan slightly more complex only tin can help eliminate fate sharing.

■

Client/Service organization encourages explicit, well-defined interfaces. Because the client and service can interact only through messages, the letters that a service is willing to receive provide a well-defined interface for the service. If those messages are well specified and their specification is public, a programmer can implement a new customer or service without having to empathize the internals of another client or the service. Clear specification allows clients and service to be implemented past different programmers, and can encourage competition for the best implementation.

Separating land and passing well-defined messages reduce the number of potential interactions, which helps contain errors. If the developer who developed the service introduces an error and the service has a disaster, the customer has only a controlled trouble. The client's only concern is that the service didn't deliver its part of the contract; autonomously from this wrong or missing value, the client has no business concern for its ain integrity. The client is less vulnerable from faults in the service, or, in slightly dissimilar words, fate sharing can be reduced. Clients can be mostly independent of service failures, and vice versa.

The client/service organisation is an example of a sweeping simplification because the model eliminates all forms of interaction other than messages. By separating the client and the service from each other using message passing, we have created a firewall between them. As with firewalls in buildings, if there is a fire in the service, information technology will be contained in the service, and, assuming the client can check for flames in the response, information technology will non propagate to the client. If the customer and service are well implemented, then the only style to go from the customer to the service and back is through well-defined letters.

Of course, the client/service organization is not a panacea. If a service returns an incorrect result, and so the client has a trouble. This client can check for certain issues (due east.thou., syntactic ones) but non all semantic errors. The client/service organization reduces fate sharing simply doesn't eliminate it. The caste to which the client/service arrangement reduces fate sharing is likewise dependent on the interface between the client and service. Every bit an extreme example, if the client/service interface has a message that allows a customer to write any value to any address in the service's address infinite, then it is piece of cake for errors to propagate from the client to the service. It is the job of the system designer to ascertain a practiced interface between client and service then that errors cannot propagate easily. In this chapter and later capacity, we will see examples of proficient message interfaces.

For ease of understanding, nearly of the examples in this chapter showroom modules consisting of a single procedure. In the real earth, designers usually apply the client/service organization between software modules of a larger granularity. The tendency toward larger granularity arises because the procedures within an application typically demand to be tightly coupled for some applied reason, such equally they all operate on the same shared data structure. Placing every procedure in a split client or service would make information technology difficult to manipulate the shared information. The designer thus faces a trade-off betwixt ease of accessing the data that a module needs and ease of mistake propagation within a module. A designer makes this trade-off by deciding which data and procedures to grouping into a coherent unit with the data that they manipulate. That coherent unit then becomes a separate service, and errors are contained inside the unit. The client and service units are often consummate application programs or similarly large subsystems.

Another factor in whether or not to use the client/service organization to two modules is the plan for recovery when the service module fails. For case, in a simulator plan that uses a function to compute the square root of its argument, information technology makes picayune sense to put that function into a carve up service because it doesn't reduce fate sharing. If the square-root role fails, the simulator program cannot proceed. Furthermore, a good recovery programme is for the programmer to reimplement the office correctly, as opposed to running two square-root servers, and failing over to the second i when the first one fails. In this example, the square-root function might too be office of the simulator programme because the client/service organisation doesn't reduce fate sharing for the simulator program and thus in that location is no reason apply it.

A nice example of a widely used system that is organized in a customer/service style, with the customer and service typically running on split computers, is the Www. The Web browser is a client, and a Spider web site is a service. The browser and the site communicate through well-defined messages and are typically geographically separated. As long as the client and service cheque the validity of messages, a failure of a service results in a controlled problem for the browser, and vice versa. The Globe Wide Web provides enforced modularity.

In Figures four.three and iv.4, the service always responds with a reply, but that is not a requirement. Figure 4.five shows the pseudocode for a pump controller for the sewage pumping system in Sidebar iv.2. In this example, there is no need for the pump service to send a reply acknowledging that the pump was turned off. What the client cares about is a confirmation from an independent sensor service that the level in the tank is going downwardly. Waiting for a respond from the pump service, even for a brusque time, would just delay sounding the alarm if the pump failed.

Figure 4.5. Instance client/service application: controller for a sewage pump.

Other systems avoid response messages for operation reasons. For example, the popular 10 Window System (encounter Sidebar 4.4) sends a series of requests that enquire the service to draw something on a screen and that individually have no need for a response.

Sidebar 4.iv

The Ten Window System

The X Window System [Suggestions for Further Reading 4.2.2] is the window organisation of choice on practically every engineering science workstation and many personal computers. It provides a proficient example of using the client/service organisation to attain modularity. I of the main contributions of the 10 Window System is that it remedied a defect that had crept into the unix system when displays replaced typewriters: the brandish and keyboard were the only hardware-dependent parts of the unix application programming interface. The X Window System allowed display-oriented unix applications to exist completely independent of the underlying hardware.

The 10 Window Organization achieved this belongings by separating the service program that manipulates the display device from the client programs that use the display. The service module provides an interface to manage windows, fonts, mouse cursors, and images. Clients can asking services for these resource through high-level operations; for example, clients perform graphics operations in terms of lines, rectangles, curves, and the similar. The advantage of this split is that the client programs are device independent. The improver of a new display type may require a new service implementation, but no application changes are required.

Another advantage of a client/service organization is that an application running on one machine tin can use the brandish on some other machine. This organization allows, for example, a computing-intensive plan to run on a high-performance supercomputer, while displaying the results on a user's personal figurer.

Information technology is important that the service be robust to client failures because otherwise a buggy client could crusade the unabridged display to freeze. The Ten Window arrangement achieves this property by having client and service communicate through carefully designed remote procedure calls, a mechanism described in Section 4.2. The remote process calls have the property that the service never has to trust the clients to provide right information and that the service tin can process other client requests if information technology has to wait for a client.

The service allows clients to ship multiple requests back to back without waiting for private responses considering the rate at which data tin can be displayed on a local display is often higher than the network data charge per unit between a client and service. If the client had to wait for a response on each asking, then the user-perceived operation would exist unacceptable. For example, at eighty characters per request (ane line of text on a typical brandish) and a 5-millisecond circular-trip time betwixt client and service, only 16,000 characters per second can be drawn, while typical hardware devices are capable of displaying an club of magnitude faster.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B978012374957400013X

Sequential Logic Design

Sarah L. Harris , David Harris , in Digital Design and Computer Architecture, 2022

Setup Fourth dimension Constraint

Figure 3.39 is the timing diagram showing just the maximum filibuster through the path, indicated by the blue arrows. To satisfy the setup time of R2, Dii must settle no after than the setup fourth dimension before the adjacent clock border. Hence, we observe an equation for the minimum clock period:

Figure 3.39. Maximum delay for setup time constraint

(iii.13) $T_c\ge t_{\mathit{pcq}}+t_{\mathit{pd}}+t_{\text{setup}}$

In commercial designs, the clock period is often dictated past the Director of Engineering or by the marketing department (to ensure a competitive product). Moreover, the flip-flop clock-to-Q propagation filibuster and setup fourth dimension, t _pcq and t _setup, are specified by the manufacturer. Hence, we rearrange Equation iii.13 to solve for the maximum propagation delay through the combinational logic, which is usually the only variable under the control of the private designer.

(three.fourteen) $t_{\mathit{pd}}\le T_c-(t_{\mathit{pcq}}+t_{\text{setup}})$

The term in parentheses, t _pcq + t _setup, is called the sequencing overhead. Ideally, the entire wheel fourth dimension T _c would exist available for useful computation in the combinational logic, t _pd . However, the sequencing overhead of the flip-bomb cuts into this time. Equation 3.14 is chosen the setup time constraint or max-filibuster constraint because it depends on the setup time and limits the maximum filibuster through combinational logic.

If the propagation delay through the combinational logic is too smashing, D2 may not have settled to its terminal value by the fourth dimension R2 needs it to be stable and samples it. Hence, R2 may sample an incorrect result or even an illegal logic level, a level in the forbidden region. In such a case, the circuit will malfunction. The problem tin can be solved past increasing the clock period or by redesigning the combinational logic to have a shorter propagation delay.

Read total chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128200643000039

Shared-retention programming

Gerassimos Barlas , in Multicore and GPU Programming, 2015

Exercises

1.

Enumerate and create the other timing diagrams that show the alternatives of Figure 3.4 when information technology comes to the terminal balance of the banking concern account.

2.

Research the term "fork bomb" and write a program that performs as such.

3.

Modify the producer-consumer example shown in Listing iii.11 and then that the threads finish later the number 100 is generated.

4.

Advise a modification to the programme of Listing 3.12 and so that the IntegrCalc threads can use whatever function that returns a double and takes a double as a parameter.

5.

In a remote region of Siberia there are single tracks joining railroad stations. Obviously only 1 train can employ a slice of rail between two stations. The other trains can wait at the stations before they do their crossings. The following graph indicates the track and station layout:

Write a Qt program that simulates the journey of 3 trains with the following schedules:

•

A  → B  → E  → C

•

D  → B  → E  → G

•

C  → Eastward  → B  → D  → F

As each trains arrives at a station, brandish a relative bulletin. You tin assume that a station tin hold any number of trains waiting.

vi.

Alter the program of the previous exercise so that each station can agree only 2 trains. Can this pb to deadlocks?

If you accept non done so already, brand sure that your program uses only one thread class.

7.

A desktop publishing application such as PageMaker has two threads running: one for running the GUI and one for doing groundwork piece of work. Simulate this awarding in Qt. Your implementation should have the thread corresponding to the GUI send requests to the other thread to run tasks on its behalf. The tasks should be (obviously but printing a message is plenty for the simulation):

•

Printing

•

Mail service merging

•

PDF generation

Afterwards performing each requested chore, the second thread should wait for a new asking to be sent to it. Make certain that the first thread does not have to expect for the second thread to terminate before making new requests.

8.

A popular bakery has a baker that cooks a loaf of bread at a time and deposits information technology on a counter. Incoming customers selection up a loaf from the counter and exit the baker. The counter can concur xx loaves. If the counter is full, the baker stops blistering staff of life. If it is empty, a customer waits. Use semaphores to solve the coordination problem between the baker and the customers.

nine.

Because of customer demand, the bakery possessor is because the following enhancements to his shop:

a.

Increase the capacity of the counter to chiliad

b.

Hire three more bakers

Modify the solution of the previous exercise to accommodate these changes.

Which is the easiest option to implement?

x.

A depository financial institution account grade is defined as follows:

class BankAccount {

  protected:

  double balance;

  string holderName;

public:

  double getBalance( ) ;

  void deposit(double);

  void withdraw(double, int); // the highest the second ↩

  statement, the higher the priority of the asking

};

Write the implementation of the three methods given above so that withdraw operations are prioritized: If there are not enough funds in the account for all, the withdrawals must be washed in order of priority, regardless of whether there are some that can be performed with the available funds. You lot can assume that the priority level in the withdraw method is past default equal to 0, and that it is upper bounded by a stock-still constant MAXPRIORITY.

11.

The Information technology department of a large corporation is equipped with five high-speed printers that are used past a multitude of threads. The threads are part of the same accounting process. Each of the threads is supposed to perform the following (pseudocode) sequence in society to print any material:

…

printerID   =   get_available_printer ( ) ;

// print to printerID printer

releasePrinter(printerID);

…

Write an advisable implementation for the two functions listed to a higher place using semaphores. You tin presume that the available printer IDs are stored in a shared buffer.

12.

Create three threads, each printing out the letters A, B, and C. The press must adhere to these rules:

•

The full number of Bs and Cs that accept been output at any point in the output string cannot exceed the total number of Every bit that take been output at that point.

•

Subsequently a C has been output, another C cannot exist output until one or more Bs have been output.

Apply semaphores to solve the problem.

13.

Alter the previous practice and then that the printing is governed by this ready of rules:

•

One C must be output subsequently two Every bit and three Bs are output.

•

Although there is no restriction on the lodge of printing A and B, the corresponding threads must await for a C to exist printed when the previous condition is met.

Use a monitor to solve the problem.

xiv.

Accost the termination trouble in the previous practice. How can the three threads terminate after, for case, a fixed number of As have been output? Or when a stock-still total number of characters accept been output?

15.

Create four threads, each printing out the letters A, B, C, and D. The printing must adhere to these rules:

•

The total number of As and Bs that have been output at whatever signal in the output string cannot exceed the total number of Cs and Ds that accept been output at that point.

•

The total number of As that have been output at any point in the output string cannot exceed twice the number of Bs that have been output at that signal.

•

After a C has been output, some other C cannot exist output until 1 or more than D accept been output.

16.

Solve the problem using (a) semaphores and (b) a monitor.

19.

Use semaphores to solve the typical cigarette smokers' problem, where the amanuensis directly signals the smoker missing the ii ingredients placed on the table.

17.

Solve the cigarette smokers' trouble as described in Section 3.half dozen.2 using semaphores.

xviii.

Model the moving picture-going process at a multiplex cinema using a monitor. Assume the following conditions:

•

There are three different movies playing at the aforementioned time in three theaters.

The capacities of each theater are 4, 5, and 7, respectively.

•

One hundred customers are waiting to see a randomly chosen picture.

•

A cashier issues the tickets.

•

If a theater is full, a moving-picture show begins to play.

•

A customer cannot enter a theater while a motion-picture show is playing or while the previous viewers are exiting the theater.

•

A movie will play for the last customers, fifty-fifty if the respective theater is not full.

19.

Write a multithreaded countersign cracker based on the producer-consumer paradigm. The producer should generate plaintext passwords according to a set of rules, and the consumers should be hashing each password and checking whether it matches a target signature. All the threads should terminate upon the discovery of a matching password. You can employ the MD5 cryptographic hash part for this do.

20.

Write a multithreaded program for finding the prime numbers in a user-supplied range of numbers. Compare the post-obit design approaches:

a.

Split the range in equal pieces and assign each one to a thread.

b.

Accept a shared QAtomicInt variable that holds the next number to be checked. Threads should read and increment this number before testing it.

c.

Have a shared "monitor" object that returns, upon asking, a range of numbers to be tested. This can be considered a generalization of the previous design.

Which of the designs is more efficient? Explain your findings.

21.

Utilize the QtConcurrent functionality to implement a prime number checker. Compare it in terms of speed, efficiency, and programming effort to your QThread -based endeavour of the previous practise.

22.

Create a big array of randomly generated 2D coordinates (ten, y). Each of the coordinates should be a number in the range [-1000, g]. Use appropriate QtConcurrent functions to find the points that are in a band of distances between 100 and 200 from the point of origin. Compare the performance of your solution against a sequential implementation.

23.

Employ the QtConcurrent functionality to implement a parallel bucketsort. Does the number of buckets play a significant role in your implementation'due south functioning?

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780124171374000034

Digit-Serial Arithmetic

Miloš D. Ercegovac , Tomás Lang , in Digital Arithmetic, 2004

9.1.1 Modes of Operation and Algorithm and Implementation Models

We consider the case in which the numerical values are represented in a radix-r number system. In some cases, we use conventional representations, while in others redundant representations are preferable.

A serial signal is a numerical input or output with i digit per clock cycle. Figure 9.i shows typical timing diagrams for a serial operation, in which in each cycle one digit of each operand is applied and one digit of the output is delivered. Note that past convention we denote every bit cycle ane the bicycle in which the beginning digit of the output is delivered. The total execution fourth dimension is the sum of two components:

Figure ix.1. Timing characteristics of serial operation with north = 12. (a) With δ = 0. (b) With δ = 3.

•

The initial delay δ, which corresponds to the additional number of operand digits required to determine the get-go event digit. That is, the showtime output digit is delivered δ + 1 cycles after the application of the showtime input digits. So, every bit shown in Figure 9.ane(a), δ = 0 corresponds to the case in which the start output digit is delivered i cycle after the application of the first input digits. Figure 9.1(b) shows a instance in which the first output is delivered in the cycle afterwards four input digits have been practical (δ = 3).

•

The time to deliver the n output digits. Since one digit is delivered per cycle, for an output of northward digits, this time is equal to northward cycles.

Consequently, the execution time is

ix.1 $T_n+\delta +1+\mathrm{north}$

Serial Modes

Two series modes are typical:

1.

Least-pregnant digit first (LSDF) way. The digits of the operands (result) are practical serially starting from the to the lowest degree-significant digit. This mode is also known as right-to-left way and, since information technology was the first serial mode, typically this style is unsaid when the term 'serial arithmetic' is used.

Because of the order of the digits, the indexing is simplified if right-to-left indexing is used, equally in the representation of integers, namely,

9.ii $x+{\displaystyle \sum _{i=0}^{n-1}{x}_i{r}^i}$

two.

Well-nigh-significant digit showtime (MSDF) mode. The digits are applied starting from the most-significant digit (left-to-correct way). Arithmetic performed in this mode is known as online arithmetic, and the respective initial filibuster is called online delay.

The indexing is simplified here by using left-to-right indexing, as in the representation of fractions, that is,

ix.3 $x+{\displaystyle \sum _{i=\mathrm{one}}^n{\mathrm{10}}_i{r}^{-i}}$

Algorithm and Implementation Model

We at present describe a general model for a serial algorithm and its implementation. Consider an functioning with 2 northward radix-r digit operands, x and y, and one result z. The input-output model is described as follows.

In wheel j the issue digit z _j+one is computed. Consequently the cycles are labeled from −δ, …, 0, 1, …, northward and so that in cycle j the operand digits ten _j+1 and y _j+1+δ are received, output digit z _j+i is computed, and output digit z_j is delivered (Figure ix.2(a)). To suit with both serial modes, in LSDF (MSDF) mode digits are counted from the least-meaning (nigh-significant) side.

Effigy 9.ii. Serial algorithm model: (a) Timing. (b) Implementation.

The algorithm consists of recurrences on numerical values. In each of the northward + δ iterations, ane digit of the operands is introduced (for the last δ iterations the input digits are set to nada), an internal state westward (as well called a balance) is updated, and i digit of the issue is produced (zero for the beginning δ cycles). ² An boosted wheel is needed to deliver the last effect digit.

Calling x[j],y[j], and z[j] the numerical values of the corresponding signals when the representation consists of the first j + δ digits for the operands and j digits for the upshot, iteration j is described past

9.four $\begin{array}{ll}\mathrm{10}\left[j+1\right]\hfill & =\left(x\left[j\right],x_{j+1+\delta }\right)\hfill \\ y\left[j+1\right]\hfill & =\left(y\left[j\right],y_{j+1+\delta }\right)\hfill \\ \hfill z_{j+\mathrm{i}}& =F\left(\mathrm{due\; west}\left[j\right],x\left[j\right],{\mathrm{ten}}_{j+1+\delta },y\left[j\right],y_{j+1+\delta },z\left[j\right]\right)\hfill \\ z\left[j+1\right]\hfill & =\left(z\left[j\right],z_{j+1}\right)\hfill \\ w\left[j+1\right]\hfill & =G\left(\mathrm{west}\left[j\right],\mathrm{ten}\left[j\right],x_{j+\mathrm{i}+\delta },y\left[j\right],y_{j+1+\delta },z\left[j\right],z_{j+1}\right)\hfill \end{array}$

Figure 9.2(b) depicts the serial algorithm and implementation model.

The initial delay δ depends on the serial mode and on the specific operation (Tabular array 9.1). As can be seen from the table, for the MSDF mode all basic operations can be performed with a small and stock-still (contained of the precision) initial delay. On the other manus, for the LSDF mode, only addition and multiplication have a modest initial delay, whereas division, foursquare root, and max/min accept an initial delay O (n), which means that this mode is not suitable for these operations. Moreover, the initial filibuster is also O (n) for multiplication if only the almost-meaning one-half of the product is required (meet Figure 9.3(a)).

Table 9.1. Initial delay (δ).

Operation	LSDF	MSDF
Improver	0	ii (r = 2)
		1 (r ≥ iv)
Multiplication	0	iii (r = 2)
		two (r = four)
Just MS half of production	n
Division	iinorth *	4
Foursquare root	2n *	4
Max/min	north	0

*

The result digits delivered LS get-go.

Figure ix.three. (a) LSDF and (b) MSDF modes.

Equally seen in Effigy 9.3(b), online arithmetic is well-suited for variable precision computations: once a desired precision is obtained, the operation can terminate.

Composite Algorithm

Since the execution time of a serial operation can be loftier, information technology is convenient to develop composite algorithms in which the execution of successive (dependent) operations overlap; that is, a successor operation tin begin as presently as the result digits of its predecessors are bachelor. This is illustrated in the post-obit instance where a sequence of operations is implemented past a network of digit-serial (online) arithmetic modules. The network in Figure nine.4(a) implements the expressions for the 2D vector normalization. ³

Figure ix.4. Online computation in 2D vector normalization: (a) Network. (b) Timing diagram.

ix.5 $\begin{array}{ll}c=\frac{x}{\sqrt{x^{\mathrm{two}}+y^{\mathrm{two}}}}\hfill & s=\frac{y}{\sqrt{{\mathrm{ten}}^2+y^2}}\hfill \end{array}$

The corresponding timing diagram is given in Figure 9.4(b).

The online delay of the network is the sum of online delays of the operations on the longest path. For r = ii, we obtain from Table 9.1

ix.6 ${\Delta }_{\mathrm{due\; north}orm}=\delta 1+\delta 2+\delta 3+\delta 4=3+2+\mathrm{four}+4=13$

The total execution time for the composite operation is D_norm = δ_norm + iv + n.

The more than levels there are in a sequence of operations and the longer the precision, the more advantageous is the online arroyo.

To reduce further the execution time, the iii modules in the dashed box in Figure ix.4(a) can be merged into a single online module, chosen a composite module, with a shorter online delay than the sum of the online delays of the dependent components.

The latency in the case of LSDF arithmetics is obtained in a similar mode (Practice 9.1).

Read full affiliate

URL:

https://www.sciencedirect.com/scientific discipline/commodity/pii/B9781558607989500117

Questions for Chapter 14

Michael Jesse Chonoles , in OCUP Certification Guide, 2018

1.

Which diagram type is non a UML 2.5 behavioral diagram?

A.

Utilise Instance Diagram

B.

Sequence Diagram

C.

Interaction Diagram

D.

Collaboration Diagram

E.

Timing Diagram

two.

Which i of the post-obit potential lifelines needs to be inverse?

A.

A

B.

B

C.

C

D.

D

3.

Which of the following letters is incorrectly drawn?

A.

a

B.

b

C.

c

D.

d

E.

e

four.

Which one of the following potential lifelines needs to be changed?

A.

A

B.

B

C.

C

D.

D

5.

Which of the messages in the beneath diagram is non uniform with the definitions shown in the class Role player?

A.

m1

B.

m2

C.

m3

D.

m4

6.

In the Sequence Diagram fragment beneath, there are three messages and half-dozen occurrences. How many dissimilar traces are at that place in this diagram?

A.

1

B.

2

C.

iii

D.

4

E.

5

F.

6

G.

7

7.

A big X is used to accomplish what purpose in a Sequence Diagram?

A.

X is the graphical end of the lifeline.

B.

X indicates the destruction of the lifeline.

C.

Ten marks the spot.

D.

X marks where to dig.

Eastward.

X marks the commencement of a balking message.

F.

X marks the start of a timed bulletin.

8.

Which lifeline needs to be replaced?

A.

a

B.

b

C.

c

D.

d

9.

What is an Interaction?

A.

An Operation call

B.

A use of an Interface

C.

A unit of measurement of Behavior

D.

A Reception

E.

An instance of a Use Case

10.

What is wrong with the following Sequence Diagram?

A.

Nothing.

B.

It is non allowed to have ii lifelines with the same proper name.

C.

There are no messages shown.

D.

Lifelines must be straight and may non cantankerous.

11.

What needs to be changed in the post-obit Sequence Diagram?

A.

The empty () needs to exist removed or filled in.

B.

The first message should move from correct to left.

C.

The arrowhead on the dashed line should be fabricated into a solid arrowhead.

D.

The m1 is a point and cannot have a return. Instead, change m1 into a synchronous operation call by making it take a solid arrowhead.

12.

How many occurrences are there in the following Sequence Diagram?

UML two.5 Specification Figure 17.2

A.

seven

B.

8

C.

ten

D.

12

E.

xiv

F.

xvi

13.

Which arrow format below indicates an asynchronous message?

A.

A

B.

B

C.

C

D.

D

E.

E

Read full chapter

URL:

https://world wide web.sciencedirect.com/science/commodity/pii/B9780128096406000167

Lasers, Solid-State

Stephen A. Payne , Georg F. Albrecht , in Encyclopedia of Concrete Science and Applied science (Third Edition), 2003

III.C.iv Cavity Dumping

A fashion of performance closely related to Q-switching is cavity dumping. The essential architecture is the aforementioned equally that for Q-switching, and the timing diagram is given in Fig. 21. The first phase of cavity-dumped operation is similar to that of Q-switching in that energy is stored. Both of the resonator mirrors are selected to be 100% reflective, such that the amplified light remains trapped within the cavity. As the peak intracavity intensity is reached, the Pockels cell speedily switches the cavity transmission off again. This ejects the light circulating in the cavity past reflection off the polarizer in a pulse whose duration is equal to two cavity passes. This technique is in essence the same as electric engineers use in a cablevision discharge, and is used to produce pulses of a few nanoseconds duration, since the pulsewidth now depends on the length of the resonator cavity and not on the corporeality of inversion stored before switching. The peak power output is significantly limited in this method since the lite circulating inside the resonator can become intense plenty to destroy critical components of the laser.

Figure 21. In the pump phase the timing diagram for the cavity-dumped case is identical to the Q-switched case. After switching the Pockels jail cell to enable lasing, the cavity loss at present is very modest since, for a cavity-dumped compages, the reflectivity of both resonator mirrors is 100%. Once the power in the cavity has reached the maximum value, the Pockels prison cell is again switched and ejects the intracavity intensity from the light amplification by stimulated emission of radiation in a pulse equal to the circular-trip time of the resonator cavity.

An architecture very closely related to the cavity-dumped oscillator is the regenerative amplifier. The principle difference is that the laser oscillation in a regenerative amplifier does non build up from spontaneous emission, but is initiated past a signal injected into the resonator from the exterior, as the Pockels cell is switched to manual. This injected signal is and so trapped in the crenel and amplified until information technology has reached maximum intensity, at which point information technology is ejected (dumped) from the cavity.

Read full affiliate

URL:

https://world wide web.sciencedirect.com/science/article/pii/B0122274105003720

Design Patterns for Embedding Concurrency and Resource Management

Bruce Powel Douglass PhD , in Design Patterns for Embedded Systems in C, 2011

Deadlock Avoidance Patterns

The last trouble I want to address in this chapter is deadlock. Deadlock is a situation in which multiple clients are simultaneously waiting for weather condition that cannot, in principle, occur.

Figure 4-22 shows an example of deadlock. In this example, the priority of Job 1 is higher than that of Task 2. The figure shows a timing diagram overlayed with a form diagram showing the construction. In addition to the tasks, there are two resources, R1 and R2, shared by both tasks. The problem arises if the tasks lock the resources in contrary club and Task 1 preempts Chore 2 between Task one between locking R1 and R2. The following description refers to the named points in Figure 4-22.

Figure 4-22. Deadlock case

A

At this point, Task 2 runs.

B

Task 2 locks R1 and is simply about to lock R2.

C

Task 1 runs. Since it is higher priority than Task 2, information technology preempts Task 2.

D

Task 1 locks R2.

E

Chore 1 at present attempts to lock R1, however, R1 is currently locked by Task two. If Chore 1 blocks to allow Chore 2 to run, Task 2 must block equally soon every bit it tries to lock R1. The system is in deadlock.

Information technology is plenty to intermission any of the four required atmospheric condition for deadlock (below) conditions to ensure that deadlock cannot announced. The simultaneous locking, ordered locking, and disquisitional region patterns all avert the bug of deadlock. For example, had Task 2 enabled a critical region (i.e., disallowed task switching) before information technology locked R1, then Task ane would not have been able to preempt it before information technology locked R2. If both tasks locked the resource in the same order, deadlock would accept been prevented. If Task 2 locks both resources at the same time, at that place would be no problem. Deadlock is like shooting fish in a barrel to prevent, just you must take careful steps to do so.

Leaving aside the common problems of software errors, deadlocks require four conditions to exist true:

ane

mutual exclusion locking of resource

2

some resource are locked while others are requested

3

preemption while resource are locked is allowed

4

a circular waiting condition exists

Deadlock can be avoided by breaking any of these four weather. Using the Disquisitional Region Pattern, for case, breaks rules #ane and #3. The Queuing Pattern, because it uses asynchronous message passing avoids #1 (other than the lock on the queue access itself). This chapter finishes up with two other patterns that avoid deadlock.

Read full chapter

URL:

https://www.sciencedirect.com/scientific discipline/commodity/pii/B9781856177078000042

DOWNLOAD HERE

How to Draw Timing Diagrams for Flip Flops TUTORIAL

Posted by: jaygialren.blogspot.com