### 电子工程代写|计算机系统原理代写Principles of Computer Systems代考|CSSE7231

statistics-lab™ 为您的留学生涯保驾护航 在代写计算机系统原理Principles of Computer Systems方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写计算机系统原理Principles of Computer Systems方面经验极为丰富，各种代写计算机系统原理Principles of Computer Systems相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 电子工程代写|计算机系统原理代写Principles of Computer Systems代考|Instruction Execution Cycle of Sequential Processor

This chapter contains an outline of structure and functioning of stand-alone internally controlled computer with sequential processor, as well as its functioning in a collection of such machines. The internal control means that program instructions (commands) and data, encoded (commonly nowadays) as sequences of bits, are located in the internal memory (RAM) and are fetched by the processor to its specific register. A distinction between instructions and data depends on this register. If it is the instruction register (IR), the bit sequence is interpreted as instruction and taken to suitable electronic circuits where it is executed, if another register, e.g. accumulator (A), it is interpreted as data. This is the so-called stored-program architecture, devised by von Neumann (1945) with J. W. Mauchly and J. P. Eckert (in the 1940s), commonly known as the von Neumann’s architecture. The details of a single instruction execution, that is actions of the electronic circuits, are on the lower description level than principles of distributed systems, so will not be considered. Why this book begins with such architecture (a brief note on alternative concepts of data processing is in the Final Remarks)? The following are some reasons:

• Multiprocessor and multicomputer distributed system is a set of such machines:
• multiprocessor-a set of processors with common physical memory,
• multicomputer-a set of stand-alone (autonomous) computers without common physical memory, possibly with diverse architectural details (e.g. different coding of numbers); the computers are connected by means of transmission channels and endowed with distributed operating system.
• The objective of the multiprocessor and multicomputer system is to give the users impression of work on a sequential, autonomous machine of enhanced performance of algorithms (due to concurrent processing of their parts) and endowed with mechanisms for joint resource usage, for interprocess communication, for correct cooperation (in particular synchronizing some actions) between other machines, etc.
• Basic functions of distributed system are similar to those in stand-alone sequential machine (Fig. 1.1); for instance, communication mechanisms in a computer network plays similar part as input/output mechanisms in a sequential machine, but are significant extension of the latter. This extension creates many problems, absent in sequential machines, where communication proceeds only between its own internal and external components.
• The book begins with demonstrative execution of simple programs by a model of sequential von Neumann’s machine and their parallel execution by a collection of such machines, connected by communication channels. Such presentation visualizes main problems of synchronization and communication in the real distributed systems.

## 电子工程代写|计算机系统原理代写Principles of Computer Systems代考|Mutual Exclusion of Processes

In order to avoid conflicts between processes that use shared resources, some mechanisms are applied ensuring access to a resource for at most one process at a time and, after its usage, giving access to this resource for another process. Such mechanisms implement mutual exclusion of processes, that is determine the so-called critical section, being a program fragment. In exclusive execution of this fragment, a protected resource is being used. Let us consider the semaphores as such mechanism, leaving out others, like TEST\&SET, as well as algorithms of mutual exclusion, for instance the Dekker’s algorithm (published in Dijkstra 1965), probably the first correct solution to this problem. The semaphore, introduced by the Dutch scientist Dijkstra $(1965,1968)$, is a variable, that assumes integer values and is shared by cooperating programs. For further considerations, the semaphores will be limited to binary ones, that is, they will assume only values 0 and 1 . Permissible operations on semaphores are named $\mathrm{P}$ and $\mathrm{V}$, and are of the following meaning, where sem is a semaphore:

• $\mathrm{P}($ sem $)$ : if $\operatorname{sem}>0$ then sem: $=\operatorname{sem}-1$, and if sem $=0$ then suspend the process
• $\mathrm{V}($ sem $)$ sem: $=1$ and resume a certain suspended process (for instance, suspended by the longest time)

The operations are indivisible (atomic): when a certain program performs one of them, another program cannot perform none of them at the same time. Thus, they are critical sections themselves, but performed at the lower level than the user’s programs (for instance by computer hardware or in the kernel of operating system). In some programming languages, the $\mathrm{P}$ operation is named ,wait” and $\mathrm{V}-$,signal” (P and V are the first letters of Dutch words “passeren” and “vrijmaken”, meaning “to pass” and “release”). They will be treated as computer’s instructions. The operations encompass arbitrarily long piece of program where exclusive access to a resource is performed, in contrast to a hardware device, called a memory arbiter, which assures exclusive read/write of a single memory cell only. Notice that the name ,semaphore” is taken from the railway terminology, because the semaphore closes entrance of program (train) to its critical section (occupied track) if another program is executing critical section which protects the same resource. This is illustrated in Table $1.4$ (with somewhat outdated steam locomotive).

## 电子工程代写|计算机系统原理代写Principles of Computer Systems代考|Instruction Execution Cycle of Sequential Processor

• 多处理器和多计算机分布式系统是一组这样的机器：
• 多处理器——一组具有公共物理内存的处理器，
• 多计算机——一组没有公共物理内存的独立（自主）计算机，可能具有不同的架构细节（例如不同的数字编码）；计算机通过传输通道连接，并具有分布式操作系统。
• 多处理器和多计算机系统的目标是给用户一个在顺序的、自主的机器上工作的印象，该机器具有增强的算法性能（由于它们的部分的并发处理）并被赋予联合资源使用机制，用于进程间通信，用于其他机器之间的正确合作（特别是同步某些动作）等。
• 分布式系统的基本功能与单机时序机类似（图1.1）；例如，计算机网络中的通信机制与顺序机中的输入/输出机制扮演着相似的角色，但却是后者的重要扩展。这种扩展产生了许多问题，在顺序机器中不存在，其中通信仅在其自己的内部和外部组件之间进行。
• 本书首先通过冯诺依曼的顺序机器模型演示简单程序的执行，以及由通过通信通道连接的这些机器的集合并行执行它们。这样的演示可视化了真实分布式系统中同步和通信的主要问题。

## 电子工程代写|计算机系统原理代写Principles of Computer Systems代考|Mutual Exclusion of Processes

• 磷(哪个)： 如果哪个>0然后 sem：=哪个−1, 如果 sem=0然后暂停进程
• 在(哪个)作为：=1并恢复某个暂停的进程（例如，暂停最长时间）

## 广义线性模型代考

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## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。