chapter 2  creating a system architecture

... actions that define the relationship between each pair of entities, and label the line with the relationship verb This is the initial ER diagram for the logical data model Answer in v04_160 9a_ act42-1.bmp ... cardinality and existence characteristics of each of the relationships defined in Exercise ! Identify cardinality For each relationship on your ER diagram, ask the question “How many of the parent ... the cardinality of each relationship and denote the entities as parent or child ! Identify existence ! For each relationship on your ER diagram, ask the question “Can the child exist if the parent...

Ngày tải lên: 21/12/2013, 06:16

... functional layer called application software ATHENA How is software categorized? ATHENA What does an operating system do? Example: ATHENA Personal Computer Operating Systems Windows, Mac OS, Linux, ... What is the software? How is software categorized? What is an operating system ? What does an operating system do? ATHENA What’s the software ? Software is the instructions and associated data, ... is software categorized? Software is categorized as either application software or system software Application software is designed to be used for a purpose such as drawing designs, creating documents,...

Ngày tải lên: 20/01/2014, 22:20

... General purpose There are also a number of general-purpose technical inlines Application The name of a software program Database The name of a database, or part of a database Email An email address ... before and after them Most can contain other block elements, and many can contain character data and inline elements Paragraphs, lists, sidebars, tables, and block quotations are all common examples ... operating system, or an operating environment: Application The name of a software program Command The name of an executable program or other software command EnVar A software environment variable...

Ngày tải lên: 21/01/2014, 06:20

Ngày tải lên: 26/01/2014, 07:20

... form as adx dr (2.14) where dr and dx are vectors, a is a matrix They can be written as dr [dr1 dr2 ··· drn ]T dx [dx u dyu dzu dbu ]T a1 1 a a       21 a3 1 a4 1 a n1 a1 2 a2 2 a3 2 a4 2 a1 3 ... similar reasons one might decide that in a three-dimensional case four satellites and four distances are needed The equal-distance trace to a fixed point is a sphere in a three-dimensional case ... IN SPHERICAL COORDINATE SYSTEM The user position calculated from the above discussion is in a Cartesian coordinate system It is usually desirable to convert to a spherical system and label the...

Ngày tải lên: 14/08/2014, 10:22

... Therefore: Gage A = 93 kPa 97.4 kPa = 4.4 kPa (gage) = + 4.4 kPa (vacuum) Gage B = 105 kPa 97.4 kPa = + 7.6 kPa (gage) Ans 2.6 Express standard atmospheric pressure as a head, h = p/ g, in (a) feet ... (dx/dz)gradient Thus dx |gradient = 2Cx , integrate ũ dx = ũ 2C dz , x = const e 2Cz/B dz B x B Ans 2.5 Atlanta, Georgia, has an average altitude of 1100 ft On a U.S standard day, pressure gage A reads ... essentially a water barometer and, in principle, could hold a column of water up to 10 ft high! 2.28 What is the uncertainty in using pressure measurement as an altimeter? A gage on an airplane measures...

Ngày tải lên: 23/10/2013, 21:15

... installation and maintenance can be accomplished quickly and easily Additionally, easy access at the MST facilitates maintenance and troubleshooting by allowing technicians to simply unplug a connector ... simplified, enabling improved reliability and maintenance Kits are available with easy instructions and materials for cleaning hardened connectors and adapters To clean the connector and adapter, the ... savings The MST hardened connector approach to any FTTX architecture provides huge operational cost advantages when compared to the installation costs of the traditional spliced architectures Cost...

Ngày tải lên: 27/10/2013, 00:15

... displacement Δx as in the case of vavg) savg total distance = ∆t Note: The average velocity and the average speed for the same time interval Δt can be quite different Instantaneous Velocity The average ... described by the algebraic sign of Δx Note: The actual distance for a trip is irrelevant as far as the displacement is concerned Consider as an example the motion of an object from an initial position ... t1 and t2 as: v − v ∆v aavg = = t2 − t1 ∆t Units: m/s2 Instantaneous Acceleration If we take the limit of aavg as Δt → we get the instantaneous acceleration a which describes how fast the velocity...

Ngày tải lên: 13/12/2013, 05:15

... tabbed indentations where you can avoid them), and XUL widgets you are familiar with 2.2.3 The XUL Namespace Like other markup vocabularies, XUL uses a namespace declaration to define the particular ... particular elements that may be included in a valid file Example 2-2 shows a sample of the required namespace declaration The namespace is an attribute of the root window element The lack of any ... document is a piece of an application interface and not a web page We'll have more to say about the window and some of its features in the second example A element that contains a ...

Ngày tải lên: 26/01/2014, 07:20

... services and features that already exist in Mozilla They can also help you organize your own work into reusable parts, such as application stylesheets, widgets, and script libraries, as described later ... features a label widget and an image, both situated within a vbox that lays them out properly in the available space These widgets make up the chrome of your application, the Mozilla user interface ... stylesheet, and a script file, for example The rest of this chapter explains how to organize and package the code in Example 2-4 and launch it as a standalone window by using the -chrome option when launching...

Ngày tải lên: 26/01/2014, 07:20

... together can be the basis for your own application development A package is a group of directories and related files that make up a Mozilla application A small, typical package may include a single ... you can always copy the examples given here to install your own application In general, to make your package registerable, create manifests that describe your package in terms that Mozilla can ... code into separate files and a package structure, and registering and launching that package are the basic building blocks of all Mozilla applications When you get a feel for what's going on...

Ngày tải lên: 26/01/2014, 07:20

... instances of a single copy of a program to execute simultaneously Background App An application can forego a user interface and run in the background only If an application is marked as a background ... created, it doesn’t initially have any views attached to (associated with) it Because drawing always takes place in a view and never directly in a window, any program that draws must define a ... messages) Marking an application as argv only means that the only information the application receives comes from the argc and argv command-line arguments that can be optionally passed to the program’s...

Ngày tải lên: 26/01/2014, 07:20

... Mechanical Electrical Functional Procedural „ Data Link ƒ Means of activating, maintaining and deactivating a reliable link ƒ Error detection and control ƒ Higher layers may assume error free transmission ... identifies unique system ƒ There is only one system with address X „ Global applicability ƒ It is possible at any system (any address) to identify any other system (address) by the global address of ... higher layer „ Changes in one layer should not require changes in other layers The OSI Environment OSI as Framework for Standardization Layer Specific Standards Elements of Standardization „...

Ngày tải lên: 16/02/2014, 08:20

... the main int dollar, quarterR, dimeR, nickelR, pennyR, remainder; Variables that are used in the main are declared There are six variables of type integer These variable names (identifiers) stand ... dollars % 10 calculate dime rolls and remainder dime_rolls = remainder / remainder = remainder % calculate nickel rolls and remainder nickel_rolls = remainder / remainder = remainder % calculate ... problem What are the known information about this programming assignemnt? There are ten dollars in a quarter roll There are five dollars in a dime roll There are two dollars in a nickel roll And there...

Ngày tải lên: 20/02/2014, 08:20

... bus architectures to interrupt vectoring and operating system privilege levels PART ADVANCED DIGITAL SYSTEMS Digital systems operate by acquiring data, manipulating that data, and then transferring ... support a larger digital system PREFACE xvii Chapter 15, “Analog Interfaces for Digital Systems,” covers the basics of analog-to-digital and digital-to-analog conversion techniques Many digital systems ... modeled by algebraic equations Rather than using arithmetic operations such as addition and subtraction, Boolean algebra employs logical operations including AND, OR, and NOT Boolean variables have...

Ngày tải lên: 05/04/2014, 22:57

... Implementation Typically, a number associated with each system call System- call interface maintains a table indexed according to these numbers The system call interface invokes intended system call ... logical conclusion It treats hardware and the operating system kernel as though they were all hardware A virtual machine provides an interface identical to the underlying bare hardware The operating ... choice of hardware, type of system User goals and System goals User goals – operating system should be convenient to use, easy to learn, reliable, safe, and fast System goals – operating system should...

Ngày tải lên: 13/05/2014, 00:36

... soma and how it manages to survive For example, a wildlife manager concerned with a specific game bird species might take an autecological vantage to managing that particular species Another example ... in adults in that particular part of the estuary particular habitat can sustain As an example, phosphorus might limit the standing crop of a nuisance blue-green algal species in a freshwater lake ... well-established autecological approach and, in this case, produced a reasonable conclusion They also adopted, with minimal adaptation, a technological paradigm from mammaliam toxicology—the LC50/LD50 Staying...

Ngày tải lên: 18/06/2014, 16:20

... type in the initial supervised classification Usually the developing urban area has more stable relationships with roads and existing urban areas than bare land; this fact was used as the decision ... fr, wetland wt, muddy beach m, built-up urban areas u, farmland fm, bare land bl and developing urban area dv A classified result based on the expert system was obtained, and the comparison between ... 18 Wetland and Water Resource Modeling and Assessment Water Built-up Urban Welland Mud Beach Forest Grassland Bare Land Farmland Developing Urban Area (a) (b) FIGURE 2.4 The overall comparison...

Ngày tải lên: 18/06/2014, 16:20

... source waters by runoff from areas where these animals leave excrement Untreated mountain streams are a source for these pathogens, as are lakes and reservoirs located near cattle farms or dairies ... water treatment can detect particles down below the size of Cryptosporidium and Giardia However, as noted in Chapter 1, organic particles are largely transparent, and thus will appear much smaller ... turbidities exceed a couple of NTU only after heavy rains or on rare occasions, a particle counter may be useful Dilution is practical with grab samplers, and online dilution systems are available, but...

Ngày tải lên: 18/06/2014, 19:20