Tài liệu PDF Disk Management

1 Global Financial Management Valuation of Stocks Copyright 1999 by Alon Brav, Stephen Gray, Campbell R Harvey and Ernst Maug. All rights reserved. No part of this lecture may be reproduced without the permission of the authors. Latest Revision: August 23, 1999 3.0 Introduction This lecture provides an overview of equity securities (stocks or shares). These securities provide an ownership interest in the firm whereas debt securities (loans, bonds or other fixed-interest securities) establish a creditor relationship with the firm. After a brief overview of some of the institutional details of these securities, this module focuses on valuing equity securities by making some simplifying assumptions. This leads us to a discussion of financial ratios that are widely used in practice, in particular, dividend yields and price/earnings multiples. After completing this module, you should be able to: • Understand basic transactions involving stocks • Demonstrate why stocks can always be valued as the present value of future dividends. • Determine the value of a stock that pays a constant dividend • Determine the value of a stock that pays a dividend that grows at a constant rate. • Use the dividend growth model to infer the expected return on equity if you know the expected growth rate of a company. • Use the dividend growth model to infer the expected growth rate of future dividends for a company where you know the expected rate of return on equity. • Value a company using appropriate P/E-multiples and understand the limitations of this methodology. • Show how the value of a company can be decomposed into the value of growth options and value of a constant earnings stream. 2 3.1 Introduction to Stocks Stocks represent an ownership interest in a company and confer three rights on the owner of a share: • Vote at company meetings: Shareholders vote on meetings on issues ranging from merger proposals to changes in the corporate charter to the election of corporate directors. • Collect periodic dividend payments. Unlike interest payments dividends are not contractually fixed and can vary. Omission of dividends does not trigger bankruptcy. • Sell the share at his or her discretion. In some countries this right can be limited. In this lecture we focus on the valuation of stocks. Therefore, we are mainly concerned with the second and third point. However, the first point is important for understanding the market for corporate control and corporate governance. Stocks are first issued to investors through what is known as the primary or new issues market. Typically, companies are founded by one or few entrepreneurs and initially held by a small number of investors. At some point the company decides to raise capital by offering shares to the general public. This is known as an initial public offering (IPO). The company may decide to raise more capital through selling shares in the future. These subsequent offerings are called seasoned equity offerings (SEO). IPOs and SEOs together form the equity primary market. In most cases companies enlist the help of an investment bank for conducting these offerings. The bank handles the distribution of shares to investors. Sometimes they also provide companies with a guarantee to sell a certain number of shares in exchange for a fee. Investors purchase stocks for their returns. These returns come in the form of: • capital gains - the appreciation in value over time, and 3 • dividends - most companies pay periodic dividends. Investors will be reluctant to purchase a stock unless there is a mechanism available for the speedy resale of these stocks. This allows them to realize capital gains and to obtain liquidity independently of the payout policy of the company. Provision of a resale mechanism is the function of the stock exchange (also known as the secondary market). Investors are able to buy and sell stocks through the stock exchange. Investors trade between themselves on Disk Management Disk Management Bởi: Phạm Nguyễn Bảo Nguyên Trong giới thiệu đến bạn thuộc tính đĩa cứng công cụ quản lý đĩa cứng Disk Management vô mạnh mẽ hữu dụng Basic Disk Basic DiskTrong làm quen với Disk Management Đầu tiên cần mắm số khái niệm định dạng ổ đĩa Windows Trong môi trường Windows ổ cứng định nghĩa gồm dạng:Basic Disk: ổ đĩa bản, dạng đĩa mặc định ta cài WindowsDynamic Disk: ổ đĩa động, dạng ỗ đĩa sau ta nâng cấp ổ Basic lên thành Dynamic, lợi ích việc nâng cấp lên ổ động khai thác tính RAID-0, RAID-1, RAID-5 mà phần sau đề cập đếnCác tính có ổ đĩa Dynamic làm được, nhiên nâng cấp từ Basic lên Dynamic liệu phân vùng bảo toàn, hạ từ Dynamic xuống Basic liệu hoàn toàn bị xoá sạchDo tuỳ theo nhu cầu sử dụng mà bạn chọn cho cách Convert đĩa thích hợp.Để chạy Disk Management bạn nhấp phải vào My Computer chọn Manage Trong cửa sổ Computer Manager click chọn Disk ManagementTrong ví dụ máy có gắn sẵn ổ cứng độc lập với nhauỔ thứ (Disk 0) 19.5Gb: chia làm phần phân vùng thứ 14.6Gb lấy làm phân vùng chứa hệ thống (Windows Server 2003), phân vùng thứ chưa định dạng cả.Ổ thứ (Disk 1) ,3 (Disk 2): 16Gb 1/33 Disk Management ổ đĩa toanh (vừa mua về) chưa định dạng cả=> Cho nên My Computer thấy ổ đĩa System (C) mà Với ổ đĩa Basic có định dạng sau:Primary partition: Với ổ cứng chung ta phép chia tối đa Primary mà phần trống không sử dụng Nên thực tế bạn không nên chia Primary, Primary đầu dung lượng tuỳ chọn với Primary thứ phải chọn hếtExtended partition: Với Extended chia nhiều phân vùng hơn, phần mở rộng cho PrimaryUnallocated: Phân vùng chưa định dạng 2/33 Disk Management Để tạo phân vùng bạn nhấp phải vào phần Unallocated chọn New Partition Trong ví dụ tạo Primary Partition trước 3/33 Disk Management Với dung lượng 2000Mb tương đương với 2Gb Tôi đặt tên cho Data1 4/33 Disk Management Tiếp tục tạo phân vùng lần Extended Partition Chọn Extended partition sau chọn Next 5/33 Disk Management Với dung lượng 2000Mb tương đương với 2Gb Khi tạo Extended partition bạn nhận thấy phần có màu xanh phần chưa định dạng thành phân vùng nói Extended chia làm nhiều phân vùng khác 6/33 Disk Management Để tạo phân vùng bạn nhấp phải vào phần Extended partition chọn New Logical Drive Với dung lượng 500Mb 7/33 Disk Management Tôi đặt tên cho Data2 Kết cho thấy phần phân vùng vừa tạo 500Mb phần trống lại 1.46Gb bạn tiếp tục tạo phân vùng cho vùng trống 8/33 Disk Management Dynamic Disk Dynamic DiskTrong phần vừa giới thiệu cho bạn cách phân vùng ổ đĩa Basic với dạng ổ đĩa liệu mà lưu ổ cứng thực không an toàn.Bạn thử tưởng tượng xem ngày đẹp trời ổ cứng bạn không may bị hỏng liệu quan trọng phân vùng Data2 bị nhiễm virus trầm trọng dẫn đến file đọc được, thật chuyện kinh khủng phải không.Chính thể để đảm bảo liệu an toàn người khuyến cáo bạn nên sử dụng công nghệ RAID, công nghệ sử dụng rộng rãi nói nôm na chúng giúp ta dự phòng liệu an toàn cách tạo thứ đĩa cứng mà chi tiết phần ta đề cập đến, RAID bao gồm dạng:RAID Hardware: người ta dùng phần cứng để định việc lưu liệu ổ cứng, phần không đề cập đến, muốn tìm hiểu thêm bạn tham khảo tài liệu kỹ thuật viên liên quan đến Mainboard, Card Raid rõRAID Software: việc dùng phần cứng để làm công việc Windows tích hợp cho ta công cụ Disk Management để làm việc nhiên để làm việc trước tiên bạn phải nâng cấp ổ đĩa Basic lên thành DynamicĐể cho thoáng hình tạm tắt nút Show/Hide Soncole Tree điBạn ý ổ đĩa bạng Basic ổ thứ & Unknown nghĩa chúng chưa định dạng 9/33 Disk Management Đầu tiên tiến hành khai báo ổ đĩa & cho hệ thống nhận cách nhấp phải vào ổ chọn Initialize Disk Chọn Disk & Disk 10/33 Disk Management Trong phần D4 phân tán nơi ổ cứng chiếm 100Mb & ổ cứng chiếm 100Mb, nhiên My computer hiển thị cho ta thấy ổ D4 (H:) với dung lượng 100Mb mà thôi=> Chúng ta khai thác 100Mb mà thôi, với tuỳ chọn ghi chép liệu lên đĩa cứng chúng ghi chép cẩn thận với thông tin lên ổ cứng nên có tốc độ chậm ổ cứng bị hỏng liệu ổ Bây bạn để ý cột:Fault Tolerance: khả chịu lỗiOverhead: Dung lượng bị điTrong dạng ta làm trước có dạng Mirrored có khả chịu lỗi mà thôi, nhiên 50% dung lượng 19/33 Disk Management Dạng Morrored dùng để dự phòng liệu quan trọng, với dạng ta tạo dự phòng cho ổ đĩa có trước mà không cần phải khởi tạo từ phân vùng trắng dạng khác Để thực ta nhấp phải vào phân vùng muốn tạo dự phòng chọn Add Mirror , ví dụ ổ System (C:) Cửa sổ Add Mirror yêu cầu bạn định ổ tạo dự phòng ví dụ chọn ổ số Disk 20/33 Disk Management Windows tự động tạo phân vùng ổ đĩa thứ tự động Copy toàn liệu phân vùng ổ thứ sang Công đoạn phải chút thời gian bạn phải chờ cho hoàn tất 21/33 Disk Management Tiếp theo tạo RAID-5 Volume với tên D5, ổ cứng đóng góp 100Mb Trong phần D5 phân tán nơi ổ cứng chiếm 100Mb & ổ cứng chiếm 100Mb & ổ cứng chiếm 100Mb, nhiên My computer hiển thị cho ta thấy ổ D5 (I:) với dung lượng 200Mb mà thôi=> Chúng ta khai thác 200Mb mà thôi, với tuỳ chọn ghi chép liệu lên đĩa cứng chúng ghi chép lên ổ cứng lúc & ổ dùng làm file ảnh để phục hồi ổ bị lỗi nên có tốc độ nhanh ổ cứng bị ... 188 6 Track Following of a Single-stage Actuator experimental performance. The above discrete-time PID controller is obtained from a continuous-time counterpart using the ZOH method with a sampling frequency of 20 kHz. Once again, we note that the above PID controller is tuned to meet the requirements on the gain and phase margins, and the design specifications on the sensitivity and complementary sensitivity functions. Although the PID control has the simplest structure, its dynamical order, which is 3, is higher than that of the RPT and CNF controllers. As expected, the complete control input is given by (6.29) 6.4 Simulation and Implementation Results In this section we present the simulation and actual implementation results of our de- signs and their comparison. The following tests are presented: i) the track-following test of the closed-loop systems, ii) the frequency-domain test including the Bode and Nyquist plots as well as the plots of the resulting sensitivity and complemen- tary sensitivity functions, iii) the runout disturbance test, and lastly iv) the PES test. Our controller was implemented on an open HDD with a sampling rate of 20 kHz. Closed-loop actuation tests were performed using an LDV to measure the R/W head position. The resolution used for LDV was 2 l um/V. This displacement output is then fed into the DSP, which would then generate the necessary control signal to the VCM actuator. The actual implementation setup is as depicted in Figure 1.7. 6.4.1 Track-following Test The simulation result and actual implementation result of the closed-loop responses for the control systems are, respectively, shown in Figures 6.6 and 6.7. It is noted that the PID control generates large overshoots in both simulation and implementation, while the systems with the RPT and CNF control have very little overshoot. We sum- marize the resulting 5% settling time, which is commonly used in the HDD research community, in Table 6.1. Clearly, the CNF control gives the best performance in the time domain compared to those of the other two systems. Table 6.1. Performances of the track-following controllers Settling time (ms) PID control RPT control CNF control Simulation 3.10 0.95 0.80 Implementation 2.65 1.05 0.85 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 6.4 Simulation and Implementation Results 189 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 1.5 Time (ms) Displacement (μm) PID (overshoot 41%) RPT CNF (a) Output responses 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 −0.05 0 0.05 0.1 Time (ms) Input signal to VCM (V) PID RPT CNF (b) Control signals Figure 6.6. Simulation result: step responses with PID, RPT and CNF control Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 190 6 Track Following of a Single-stage Actuator 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Time (ms) Displacement (μm) PID (overshoot 31%) RPT CNF (a) Output responses 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 −0.05 0 0.05 0.1 Time (ms) Input signal to VCM (V) PID RPT CNF (b) Control signals Figure 6.7. Implementation result: step responses with PID, RPT and CNF control Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 6.4 Simulation and Implementation Results 191 We believe that the shortcoming of the PID control is mainly due to its structure, i.e. it only feeds in the error signal, , instead of feeding in both and inde- pendently. We trust that the same problem might be present in other control methods if the only signal fed is . The PID control structure might well be as simple as most researchers and engineers have claimed. However, the RPT controller is even simpler, but it and the CNF controller have fully utilized all available information associated with the actual system. Unfortunately, we could not compare our results with those in the literature. Most of the references we found in the open literature contained only simulation results in this regard. 8.4 Simulation and Implementation Results 239 which is the same as those in the previous chapters, to our servo systems. The im- plementation results of the corresponding responses are respectively shown in Fig- ures 8.20 to 8.22. 0 10 20 30 40 50 60 70 80 90 100 0.3 0.4 0.5 0.6 0.7 RRO disturbance (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) Time (ms) Single−stage Dual−stage Figure 8.20. Implementation results: Responses to a runout disturbance (PID) 8.4.4 Position Error Signal Test Lastly, as were done in Chapters 6 and 7, we conduct the PES tests for the complete single- and dual-stage actuated servo systems. The results, i.e. the histograms of the PES tests, are given in Figures 8.23 to 8.25. The 3 values of the PES tests, which are a measure of track misregistration (TMR) in HDDs and that are closely related to the maximum achievable track density, are summarized in Table 8.2. Table 8.2. The values of the PES tests 3 ( l um) PID control RPT control CNF control Single-stage 0.0615 0.0375 0.0288 Dual-stage 0.0273 0.0204 0.0195 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 240 8 Dual-stage Actuated Servo Systems 0 10 20 30 40 50 60 70 80 90 100 0.3 0.4 0.5 0.6 0.7 RRO disturbance (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) Time (ms) Single−stage Dual−stage Figure 8.21. Implementation results: Responses to a runout disturbance (RPT) 0 10 20 30 40 50 60 70 80 90 100 0.3 0.4 0.5 0.6 0.7 RRO disturbance (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) 0 10 20 30 40 50 60 70 80 90 100 −0.05 0 0.05 Error (μm) Time (ms) Single−stage Dual−stage Figure 8.22. Implementation results: Responses to a runout disturbance (CNF) Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 8.4 Simulation and Implementation Results 241 −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points Single−stage Dual−stage Figure 8.23. Implementation results: PES test histograms (PID) −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points Single−stage Dual−stage Figure 8.24. Implementation results: PES test histograms (RPT) Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 242 8 Dual-stage Actuated Servo Systems −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points −0.1 −0.05 0 0.05 0.1 0 1000 2000 3000 4000 5000 6000 Error (μm) Points Single−stage Dual−stage Figure 8.25. Implementation results: PES test histograms (CNF) It can be easily observed from the results obtained that the dual-stage actuated servo systems do provide a faster settling time and better positioning accuracy com- pared with those of the single-stage actuated counterparts. The improvement in the track-following stage turns out to be very noticeable. This was actually the origi- nal purpose of introducing the microactuator into HDD servo systems. However, we personally feel that the price we have paid (i.e. by adding an expensive and delicate piezoelectric actuator to the system) for such an improvement is too high. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 9 Modeling and Design of a Microdrive System 9.1 Introduction Chapters 6 to 8 focus on the design of single- and dual-stage actuated hard drive servo systems. The hard drives considered are those used in normal desktop computers. As mentioned earlier in the introduction chapter, microdrives have become popular these days because of high demand from many new applications. Many factors such as frictional forces and nonlinearities, which are negligible for normal drives and Systems Research and Behavioral Science Syst. Res. 23,157^168 (2006) Published onlineinWiley InterScience (www.interscience.wiley.com) DOI:10.1002/sres.751 & Research Paper A Knowledge Management System for ERP Implementation Yuan Li*, Xiu Wu Liao and Hong Zhen Lei School of Management, Xian Jiaotong University, Xian, China An enterprise resource planning (ERP) is an enterprise-wide application software package that integrates all necessary business functions into a single system with a common database. Its implementation is a complex process in terms of technology pre- paration and organizational change management. Although the importance of knowledge management (KM) in ERP implementation has been recognized, how to conduct knowledge management has not received deserved attention till now. The main objective of this paper is to develop a KM system to manage the knowledge of ERP implementation process. To accomplish this, the article first identifies the types of knowledge in ERP implementation. It then summarizes various KM activities based on a six-stage model. At last, it proposes a KM system that consists of cooperative working platform, consulting platform, individual KM platform, organizational KM platform, and knowledge transfer platform. This system can effectively manage knowledge and provide support for the successful implementation of an ERP system. Copyright # 2006 John Wiley & Sons, Ltd. Keywords enterprise information systems; enterprise resource planning; knowledge manage- ment; systems research; systems engineering; systems approach; MIS; management information systems INTRODUCTION In today’s dynamic and unpredictable business environment, companies face the tremendous challenge of expanding markets and rising custo- mer expectations. This compels them to lower total costs in the entire supply chain, shorten throughput times, reduce inventories, expand product choice, provide more reliable delivery dates and better customer service, improve quality, and efficiently coordinate globe demand, supply and production (Li, 2000a; Li and Li, 2000; Umble et al., 2003). In order to accomplish these objectives, more and more companies are turning to the enterprise resource planning systems (ERP). An ERP is a packaged enterprise-wide information system that integrates all necessary business functions, such as product planning, purchasing, inventory control, sales, financial and human resources, into a single system with a shared database (Alavi and Leidner, 2001). Copyright # 2006 John Wiley & Sons, Ltd. * Correspondence to: Yuan Li, School of Management, Xian Jiaotong University, Xian 710049, China. E-mail: liyuan@xjtu.edu.cn Contract/grant sponsor: NSFC; contract/grant numbers: 70121001; 70472039; 70571063. A successfully implemented ERP can offer companies the follow ing three major benefits (Yusuf et al., 2004): * Automating business process * Timely access to management information * Improving supply chain management through the use of e-commerce In the past few years, thousands of companies around the world have implemented ERP systems. The number of companies that plan to implement ERP is growing rapidly. AMR Research, an authoritative market forecast insti- tution in America, indicated that the ERP market would grow at annual rate of 37% in recent 5 years. The sales of the ERP packaged software are estimated to be around $20 billion by the year 2000 and the eventual market size is predicted to be around $1 trillion by the year 2010 (Rajagopal, 2002). Even in China, a developing country, ERP has also become a main product in the software market and the sales have approached six hundreds million RMB in the first half of 2002 (Li, 2000b; Li et WHITE PAPER: ENTERPRISE SECURITY IT Risk Management for Financial Services An Essential Strategy for Business Success Contents Executive summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 The challenge to the enterprise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Five steps to risk management best practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Symantec’s approach to best practices implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Putting our strategy to work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 White Paper: Enterprise Security IT Risk Management for Financial Services An Essential Strategy for Business Success Executive summary Assuming and managing risk is one of the important roles the financial services industry plays for its customers. 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The Sarbanes-Oxley Act in the United States, and Basel II globally have made all levels of operational risk management, including IT risk, a board-level topic in every major financial institution today. These regulations require increased control and effective management of information assets throughout the institution. As a part of meeting these requirements, successful, forward-looking enterprises are developing specific strategies and policies for IT risk management. IT risk management involves two complementary components: security and availability. Information is worthless and can even be a liability, if it’s not secure. Secure information is useless if it can’t be efficiently stored and readily accessed. IT Risk Management for Financial Services: An Essential Strategy for Business ... chúng chưa định dạng 9/33 Disk Management Đầu tiên tiến hành khai báo ổ đĩa & cho hệ thống nhận cách nhấp phải vào ổ chọn Initialize Disk Chọn Disk & Disk 10/33 Disk Management Sau nâng cấp ổ... Dynamic cách nhấp phải vào ổ địa chọn Convert to Dynamic Disk Chọn ổ đĩa Disk & Disk & Disk Sau nhấp chọn Convert để tiến hành nâng cấp 11/33 Disk Management Chọn Yes Sau Windows thông báo Restart... chọn ổ số Disk 20/33 Disk Management Windows tự động tạo phân vùng ổ đĩa thứ tự động Copy toàn liệu phân vùng ổ thứ sang Công đoạn phải chút thời gian bạn phải chờ cho hoàn tất 21/33 Disk Management