ITS 116C (Discrete Structure)

2010-01-25T21:13:00.000-08:00

Creating Custom Toolbars =
Just as menu bars are staples for keyboard users.toolbars are used by mouse-oriented users to quickly execute functions of your applications.Think of toolbars as mouse shorcuts. In general you should have one toolbar for every menu in your program.When you display a menu you should also display a corresponding toolbar.

A toolbars dialog box shows you a list of all toolbars access. You can use it to
>Customize an existing toolbar
>Create a new toolbar
>Select color or black-abnd-white buttons
>Select large orsmall buttons
>Choose to display tooltips
All currently displayed toolbars have a check mark next to thier names.

To customize a toolbar. the toolbar must be displayed. To display a toolbar.Click on the check box to the toolbar you want to display.When all the toolbars you want to customize are displayed.

=cstomizing a toolbar consists of four basic function:

>Adding buttons to toolbars
>Removing buttons from toolbars
>Moving the face (image)of toolbar buttons
Adding Buttons to a toolbar =
To customize toolbars dialog box
>A category list
>A view of all or objects for the selected category
Removing buttons from a toolbar=
>The function isn't used
>A toolbutton that is used morte frequently will replace it.
>Users shoudn't be allowed to perform the function.
Moving buttons on toolbar=
You can move toolbuttons on a toolbar or move buttons from one toolbar to another. You should always attempt to place toolbuttons into logical groups.
Example: Microsoft Word separates paragraph alingment buttons from text formatting buttons.

Changing button faces on toolbars
There are three merhods for customizing the image of a toolbuttons.

>Copy and Paste an image using the clipboard.
>Select a bitmap from access supplied images
>Using an image using the built in Button Editor.
Copy and Paste an image by using the clipboard

1.Display the image in the graphic editor of your choice
2. Use the editor's function to copy the inage to the clipboard
3. Open the shorcut menu of the toolbutton you ant to change
4. Select Paste Button image

You can also copy the image from one toolbutton to another.to do this
1.Open the shorcut menu of the toolbutton you want to copy the image from
2.Select Copy button aimage
3. Open the shorcut menu of the toolbutton you want to change
4. Select Paste button image

Hiding Access displaying toolbars=After you have defined all the toolbars for you application you need to control when and which toolbars are shown to. Toolbars can be hidden or shown any time using the the show.

Allowing users to modify your custom toolbars=

1.Uncheck the allow toolbar changes box on the application srartup dialog box
2.Set allow toolbar changes proverty of the sApplication objject to false.

ASSIGN_02

2009-12-09T19:38:00.001-08:00

TWO ARTICLES RE OF DATABASE

SQL Azure with ASP Dot Net
By Don Schlichting

Introduction
SQL Azure (SSDS - SQL Server Data Services) is a cloud database system offered by Microsoft. We interact with the SQL Azure services by either issuing statements to it though a command prompt or developing Dot Net applications. This article will introduce and demonstrate development of SQL Azure ASP Dot Net applications.
Connecting
Connecting to SQL Azure is similar to connecting to a traditional SQL Server. A connection string is created then opened. To begin with SQL Azure, create an account from the Microsoft Azure web site. Once the account is created, log in and navigate to the Server Administration page. Select the master database (master is automatically created for us when the Azure account is created), and then select “Connection Strings”. A popup will display the connection string for ADO Dot Net and ODBC. Copy the ADO Dot Net string. On the next tab, Firewall Settings, create a rule to allow your client machine access as shown below.

To Partition or Not to Partition in E-Business Suite
By Steve Callan

As a database administrator, there are two kinds of databases you are likely to own: those you design and those you inherit. In this article, we’ll look at what takes place during the design phase, and then apply the lessons there to a real world implementation, courtesy of Oracle E-Business Suite.
As many database design books tend to illustrate, there are two structures to keep in mind when designing a database, and those are logical and physical. The logical structure is usually what comes to mind when visualizing a layout, where the visual image is materialized into an entity relation diagram (ERD) courtesy of a tool. The logical layout helps to diagram how the database (or more specifically, the application) will operate. Details filled in here include how tables are organized with respect to attributes. As an example, if you have a table dealing with people, how are those people further classified? You could have one table “managing” everything about people, regardless of where they exist (i.e., internal or external to your organization).
In this super table, using employees and customers as a simple classification, not all columns or attributes apply to a person (would an employee have a shipping address versus would a customer have a hire date?). If you prefer to segregate people, then two tables could be used. This approach leads to more tables (it can be applied to more than just people), but there are benefits related to performance since there are smaller sets of data to examine (which leads to a hint where this is going).
Continuing on, once all the tables are designed, what happens next is table creation. The big mistake or hobbling event here is that the physical table is created as a direct mapping of the logical table. In other words, you could look at many databases and see a direct mapping of the ERD/logical table in the physical structure of the database. The pitfall here is that the physical design often fails to take performance-enhancing features into account. The functional layout may be quite valid, but the physical layout has immediately introduced obstacles to good or acceptable performance.
A classic example of this involves partitioning, or the lack thereof. This is less likely to happen during the design of a data warehouse because by now, the inclusion of partitioning in a warehouse is a common, well-known practice. However, this is not always the case in non-warehouse databases, where partitioning can certainly help improve performance and make administration easier to perform. Most tables are heap tables, and the term heap connotes a pile, and that is what most databases are: a pile of tables.
Other types of tables to consider when going from the logical to the physical include index organized tables. An ERD-diagrammed picture of a table isn’t necessarily going to tell you “make this table IOT when you create it.” Other table options are available, such as external, temporary, and object (why would you ever use that?), so keep them in mind before blindly laying down a logical table into a physical one without any other considerations.
That consideration seems like a fairly common sense approach, but sometimes common sense loses out to cents, as in paying much more for a feature that would make an application run better in the first place. This brings us to the Oracle Applications/E-Business Suite tie-in where the logical is the physical, unless you pay more to make the physical perform better. How and why do we know this?
Oracle Support has published a 53-page document regarding the use of partitioning within EBS (Using Database Partitioning with Oracle E-Business Suite, An Oracle White Paper, March 2009). This white paper updates/replaces the first version published in February, 2008 (with the slightly different title of Database Partitioning for Oracle E-Business Suite). The majority of the white paper explains what partitioning is and how to use it, which is basically a repeat of what is already contained in “real world” Oracle documentation (as opposed to “Oracle Apps world” documentation). If you are already familiar with partitioning, the relevant part of the white paper is the table titled “Examples of Partition Keys for Oracle Application Tables.”
The suggestion for partitioning encompass ten tables, along with the type of partitioning and the partitioning key (one table is listed twice). So, does Oracle Apps have any partitioning or is what is listed in the white paper a drill in implementing this feature from scratch? The answer to both is yes. In version 11.5.10, and excluding SYSTEM, 110 tables are partitioned. These tables install that way by default, and do not support user modification. By not supported, what is meant is this:
Modifying existing base product indexes and tables that have already been partitioned is not recommended or supported as it can cause application errors.
So, supported means you can add custom partitioning, but don’t mess with existing partitioned objects. The other tables, the list of which being a starting point and not meant to be all inclusive, are left for you to transform from normal tables to partitioned tables (and don’t forget to consider partitioned indexes).
Taking the list of tables and doing a look-see of what’s in an existing implementation (an 11.5.10 database), the results show some moderately sized tables. Note: not all tables may appear as this depends on additional modules you have licensed.

ASSIGN_01

2009-11-18T23:15:00.000-08:00

Contrast Hierarchical and Relational Database
A.) Hierarchical Database
A database organization method that is structured in a hierarchy. All access to data starts at the top of the hierarchy and moves downward; for example, from customer to orders, vendor to purchases, etc. Contrast with relational database and network database.
B.) Relational Database
A relational database matches data by using common characteristics found within the data set. The resulting groups of data are organized and are much easier for people to understand.
For example, a data set containing all the real-estate transactions in a town can be grouped by the year the transaction occurred; or it can be grouped by the sale price of the transaction; or it can be grouped by the buyer's last name; and so on.
Such a grouping uses the relational model (a technical term for this is schema). Hence, such a database is called a "relational database."
The software used to do this grouping is called a relational database management system. The term "relational database" often refers to this type of software.
Relational databases are currently the predominant choice in storing financial records, manufacturing and logistical information, personnel data and much more.

my_idea_Is

2009-08-16T03:12:00.000-07:00

A.Discuss what have you learn and undestood what is relationship of DBMS,so far?

The DBMS is interact to the computer system to store data,is just an application that let you store the informatiojn of database and responsible to build the database,storage devices to build data structure in order you to have database.The DBMS to maintain the data structure,data,database.
The data is a representation of facts,concepts or instructions in a formalized manner suitable for communication,interpretation or processing by human beings or by automatic means.Well managed data can save time,money,increase productivity.
Database-A computer database is a program that lets you store,manage and manipulate data.

B.Define how each of the following fit and function within the framework of relational DBMS system:
1.)key fields -primary key,foreign key
2.)Database Records-holds record of the database
3.)Data Queries-allows us to store data in different ways
4.)Data types-
5.)Data forms-allows us to build a user-friendly interface for our user
6.)Tables/Database-allowa to make a table in plan our database
7.)Relationships(table linkages)-allow us to format a data in table for linkages

MY_ASSIGNMNT

2009-07-02T04:04:00.000-07:00

A. What are data types?

A data type in a programming language is a set of data with values having predefined characteristics. Examples of data types are: integer, floating point unit number, character, string, and pointer. Usually, a limited number of such data types come built into a language. The language usually specifies the range of values for a given data type, how the values are processed by the computer, and how they are stored.With object-oriented programming, a programmer can create new data types to meet application needs. Such an exercise as known as "data abstraction" and the result is a new class of data. Such a class can draw upon the "built-in" data types such as number integers and characters. For example, a class could be created that would abstract the characteristics of a purchase order. The purchase order data type would contain the more basic data types of numbers and characters and could also include other object defined by another class. The purchase order data type would have all of the inherent services that a programming language provided to its built-in data types.Languages that leave little room for programmers to define their own data types are said to be strongly-typed languages.

B. What role do they play in a database?

Data Types -- The Easiest Part of Database DesignDatabase design can be very complicated, and it truly is an art as opposed to a science; sometimes there are multiple correct ways to model the same data with pros and cons to each. I can understand that normalization can be tricky to comprehend and to implement, and that concepts like stored procedures and foreign keys and even indexes and constraints can take time to grasp.But -- what about Data Types? They are so basic, so simple, so fundamental; not only for database design, but for any sort of programming in general ... what excuse is there for not using correct data types for the columns in a table design?I see it time and time again in the SQLTeam forums -- "dates" that don't sort properly, "numbers" that don't add correctly, "boolean" columns containing 10 different values, invalid entries that somehow show up in "date" columns, and so on ... Of course, since we are rarely provided any DDL to review, it often takes dozens of posts going back and forth until we finally realize: "wait ... you aren't using a datetime data type to store these dates??? Arggh!!"In short, even a poorly designed database, with one giant "master" table with no normalization or logic anywhere in sight, should still at least use a Money data type to store currency values!Perhaps the confusion comes from Excel users, where data types are handled behind the scenes ... or maybe "old school" VB programmers used to using variant data types (or worse -- undeclared variables!) to store values... But when you design a table in any database, you are always explicitly stating the data types of the columns -- there's nothing hidden, or no option to ignore them. You must declare a data type when creating a column, so how can anyone justify using VARCHAR to store a date?

C. Enumerate 3 data types of DBMS and explain.

1. Fixed-length textThe char data type is used to store fixed-length text with up to 255 characters. Specifying the number of characters to store limits how big the column will be. Text values retrieved from a char column are padded with spaces, if necessary, to the size of the column. The char data type is not available from the Access designer.The following statement creates a table with a 10-character text column and a 255-character text column, both with Unicode compression:CREATE TABLE T1 (c1 char(10) WITH compression, c2 char WITH compression)2. Variable-length textThe varchar data type is used to store variable-length text with up to 255 characters.Text values retrieved from a varchar column are trimmed of any trailing spaces.The following statement creates a table with a 10-character text column and a 255-character text column, both with Unicode compression:CREATE TABLE T2 (c1 varchar(10) WITH compression, c2 varchar WITH compression)3. Text BLOBThe longchar data type is used to store variable-length text with an unspecified number of characters, limited only by the maximum size of JET database files (2 GB – about 1 billion uncompressed Unicode characters).Some software libraries are able to handle longchar columns as basic text columns, but others must use BLOB techniques for accessing their data. In particular, the ADO components so often used in Visual Basic, VBA and ASP applications can access longchar columns as basic text when using the JET 4.0 OLE-DB provider to access the database, but must use BLOB handling routines (GetChunk / AppendChunk) when using an ODBC connection.The following statement creates a table with two variable-length text BLOB columns, both with Unicode compression:

MV vs. DATAF

2009-06-27T03:06:00.001-07:00

Characteristics of Memory Variable:

* Memory variable files are a way to store the status of memory variables that are currently stored in memory and use them later in the same program or in another session of FoxPro.
The memory location holds values- perhaps numbers or text or more complicated types of data like a payroll record. Operating Systems load programs into different parts of RAM so there is no way of knowing exactly which memory location will hold a particular variable before the program is run. By giving a variable a symbolic name like "employee_payroll_id" the compiler or interpreter can always work out where to store the variable in memory.

Characteristics of Data Field:

* A data field is the smallest subdivision of the stored data that can be accessed. A data field can be used to store numerical information such as price, count or a date or time, or even a data and time. A pair of data fields can be used in combination to hold a geo-spatial coordinate. Also, a data field can be used to hold a block of text. A data field takes up permanent storage within the data-store. The field may contain data to be entered as well as data to be displayed.

ITS 121B TERM CONTRAST

2009-06-21T23:29:00.000-07:00

A.Data vs. Information
=Data: (ISO) A representation of facts, concepts or instructions in a formalised manner suitable for communication, interpretation or processing by human beings or by automatic means.Letters, numbers, colours, symbols, shapes, temperatures, sound or other facts and figures are data suitable for processing.
Information: (ISO) The meaning that is applied to data by means of the conversions applied to that data. I.E. processed data.

Data
Raw material for computer processing for example, numbers, text, images, and sounds, in a form that is suitable for storage or processing by a computer.
• The ability to gather, store, process, and retrieve data in a timely manner is vital
• Well managed data can
– save time and money
– increase productivity
– enhance decision making

Information
Computer data that has been organized and presented in a systematic fashion to clarify the underlying meaning.

B.Computer storage vs.Data Storage

=
Data storage vs. computer storage
Computer data storage
computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.
In contemporary usage, memory usually refers to a form of semiconductor storage known as random access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage today more commonly refers to mass storage - optical discs, forms of magnetic storage like hard disks, and other types slower than RAM, but of a more permanent nature. Historically, memory and storage were respectively called primary storage and secondary storage.
The contemporary distinctions are helpful, because they are also fundamental to the architecture of computers in general. The distinctions also reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.
Any data storage device; that records (stores) or retrieves (reads) information (data) from any medium, including the medium itself. A data storage device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy, spanning from manual muscle power in handwriting, to acoustic vibrations in phonographic recording, to electromagnetic energy modulating magnetic tape and optical discs.
A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store and retrieve information.

C.OPERATING SYSTEM VS. COMPUTER SYSTEM

=
Operating system (commonly abbreviated to either OS or O/S) is an interface between hardware and user; it is responsible for the management and coordination of activities and the sharing of the resources of the computer. The operating system acts as a host for computing applications that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. This relieves application programs from having to manage these details and makes it easier to write applications. Almost all computers (including handheld computers, desktop computers, supercomputers, video game consoles) aswell as some robots, domestic appliances (dishwashers, washing machines), and portable media players use an operating system of some type. [1] Some of the oldest models may however use an embedded operating system, that may be contained on a compact disk or other data storage device.
Operating systems offer a number of services to application programs and users. Applications access these services through application programming interfaces (APIs) or system calls.

The Computer System Hardware category groups classes together that represent hardware related objects. Examples include input devices, hard disks, expansion cards, video devices, networking devices, and system power.

Data structure except the reported one

2009-03-01T19:14:00.000-08:00

Linked List

is one of the fundamental data structures, and can be used to implement other data structures. It consists of a sequence of nodes, each containing arbitrary data fields and one or two references ("links") pointing to the next and/or previous nodes. The principal benefit of a linked list over a conventional array is that the order of the linked items may be different from the order that the data items are stored in memory or on disk, allowing the list of items to be traversed in a different order.

How it access

If you have read books on memory then you would have come across a concept similar to linked lists. All these books usually explain one method for remembering the names of random objects in order. For example, your friend might read out the following list to you just once:
Sheep, carpet, bottle, cigar, tent
and throw a challenge. The challenge is that after a few minutes you should be able to recollect the five names in the same order. Not a big deal, right? Try it with 20 and you’ll realize the difficulty. Memory experts suggest that we associate each object with the next one in the list; or in other words create a link between every neighbouring object. In our case we might say, “A sheep was born on a carpet, the carpet was rolled into a bottle, the bottle smoked a cigar, the cigar was resting in a tent!” The idea is to form comical associations between two objects since these associations are retained in our memory longer. The beauty of this technique is that if your friend names any object from the list, you will be able to say what is the next object in the list (irrespective of the object’s position in the list).

Actual structuring

To aid in the understanding of the linked list concept, let's write a little program which will simulate a linked list. The program should do the following:
Store a set of integers.
It should be possible to delete a particular element.
Permit insertion of a new node (element).
Deletion of a particular node.
A way to display the entire contents of the list.
Let's do this program the OOPs way. First of all we need to have an idea about how we are going to represent a single node of the linked list. The simplest way is to use a structure for a node.

struct node
{
int data;
node *next;
};
'data' is used to hold the data. In this case we are creating a linked list to store only integers (so 'data' is of type int). Every node contains a pointer to the next node. For this we create a pointer pointing to an object of type 'node'. Thus the pointer 'next' will contain the address of the next node.

How is data kept

A data structure is simply a way of organizing data and we have organized data in our shopping list as well. From what we’ve learnt so far we would categorize this as an array perhaps. The information isn’t sorted and we simply keep increasing the list when we think of more things to buy. But the problem with arrays is that they are fixed. You can’t keep on increasing their size as and when you feel like it. So we have a better data structure called a vector to serve this purpose.

"Defined ITS 116"

2009-03-01T18:09:00.001-08:00

Kind of Data structure

Definition of Stack

A stack is a data structure that allows items to be added and removed from one end. That's why it's also described as a LIFO stack. Last In First Out. A stack can be directly compared to some real-life objects. For example, a stack of trays. Trays are only added and removed from the top. A stack of exercise books can also be used as another analogy. Students only take away or pass up exercise books from the top.

Definition of Dictionary

An abstract data type storing items, or values. A value is accessed by an associated key. Basic operations are new, insert, find and delete.
Formal Definition: The operations new(), insert(k, v, D), and find(k, D) may be defined with axiomatic semantics as follows.
new() returns a dictionary
find(k, insert(k, v, D)) = v
find(k, insert(j, v, D)) = find(k, D) if k ≠ j

where k and j are keys, v is a value, and D is a dictionary.

Definition of Bag

An unordered collection of values that may have duplicates.
Formal Definition: A bag has a single query function, numberIn(v, B), which tells how many copies of an element are in the bag, and two modifier functions, add(v, B) and remove(v, B). These may be defined with axiomatic semantics as follows.
new() returns a bag
numberIn(v, new()) = 0
numberIn(v, add(v, B)) = 1 + numberIn(v, B)
numberIn(v, add(u, B)) = numberIn(v, B) if v ≠ u
remove(v, new()) = new()
remove(v, add(v, B)) = B
remove(v, add(u, B)) = add(u, remove(v, B)) if v ≠ u
where B is a bag and u and v are elements.

Definition of Set

An unordered collection of values where each value occurs at most once. A group of elements with three properties: (1) all elements belong to a universe, (2) either each element is a member of the set or it is not, and (3) the elements are unordered.
Formal Definition: As an abstract data type, a set has a single query function, isIn(v, S), which tells whether an element is a member of the set or not, and two modifier functions, add(v, S) and remove(v, S). These may be defined with axiomatic semantics as follows.
new() returns a set
isIn(v, new()) = false
isIn(v, add(v, S)) = true
isIn(v, add(u, S)) = isIn(v , S) if v ≠ u
remove(v, new()) = new()
remove(v, add(v, S)) = remove(v, S)
remove(v, add(u, S)) = add(u, remove(v, S)) if v ≠ u
where S is a set and u and v are elements.

Definition of Graph

In computer science, a graph is a kind of data structure, specifically an abstract data type (ADT), that consists of a set of nodes (also called vertices) and a set of edges that establish relationships (connections) between the nodes. The graph ADT follows directly from the graph concept from mathematics.
Informally, G=(V,E) consists of vertices, the elements of V, which are connected by edges, the elements of E. Formally, a graph, G, is defined as an ordered pair, G=(V,E), where V is a set (usually finite) and E is a set consisting of two element subsets of V.

Definition of Buffer

In computing, a buffer is a region of memory used to temporarily hold data while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such as a keyboard) or just before it is sent to an output device (such as a printer). However, a buffer may be used when moving data between processes within a computer. This is comparable to buffers in telecommunication. Buffers can be implemented in either hardware or software, but the vast majority of buffers are implemented in software. Buffers are typically used when there is a difference between the rate at which data is received and the rate at which it can be processed, or in the case that these rates are variable, for example in a printer spooler.

Definition of Hash Table

In computer science, a hash table, or a hash map, is a data structure that associates keys with values.
The primary operation that hash functions support efficiently is a lookup: given a key (e.g., a person's name), find the corresponding value (e.g., that person's telephone number). It works by transforming the key using a hash function into a hash, a number that is used as an index in an array to locate the desired location ("bucket") where the values should be.
In most cases the hash function is deliberately chosen to have pseudo-random properties, so that small changes of key gives a large and apparently random effect (although of course reproducible effect) on the hash returned. Because of this random effect in some cases the calculated index can be the same for two different keys (a "collision"); different hash table designs handle this issue in different ways.

Definition of Skip List

A skip list is a probabilistic data structure, based on multiple parallel, sorted linked lists, with efficiency comparable to a binary search tree (order log n average time for most operations).
Underlying the skip list is an augmentation of an ordered linked list with additional forward links, added in a randomized way with a geometric/negative binomial distribution [1], so that a search in the list may quickly skip parts of the list (hence the name). Insert, search and delete operations are performed in logarithmic randomized time.

Definition of Bitboard

A bitboard, often used for boardgames such as chess, checkers and othello, is a specialization of the bitset data structure, where each bit represents a game position or state, designed for optimization of speed and/or memory or disk use in mass calculations. Bits in the same bitboard relate to each other in the rules of the game often forming a game position when taken together. Other bitboards are commonly used as masks to transform or answer queries about positions. The "game" may be any game-like system where information is tightly packed in a structured form with "rules" affecting how the individual units or pieces relate.

Definition of Priority Queue

A priority queue is an abstract data type in computer programming that supports the following three operations:

InsertWithPriority: add an element to the queue with an associated priority
GetNext: remove the element from the queue that has the highest priority, and return it (also known as "PopElement(Off)", or "GetMinimum")
PeekAtNext (optional): look at the element with highest priority without removing it

"Array"

2009-02-05T03:22:00.000-08:00

An array is a series of elements of the same type placed in contiguous memory locations that can be individually referenced by adding an index to a unique identifier. That means that, for example, we can store 5 values of type int in an array without having to declare 5 different variables, each one with a different identifier. Instead of that, using an array we can store 5 different values of the same type, int for example, with a unique identifier.

For example, an array to contain 5 integer values of type int called billy could be represented like this:
0 1 2 3 4
billy ____
int

where each blank panel represents an element of the array, that in this case are integer values of type int. These elements are numbered from 0 to 4 since in arrays the first index is always 0, independently of its length.

First index (0)

0 1 2 3 4 5 6 7 8 9 -----indices

billy ____ __ Element (at indexes 8)

---------------Array length is 10-------------------

Array dimensions:

In the most of cases the Array has one dimension like the description above, but in some case the Array has more than one dimension (In MQL4 the maximum dimension is four dimensions).Multi-dimensional arrays are very like multi-column tables, where the first column is the first dimension of the Array and the second column is the second dimension of the Array etc.

Creating an Array:

The arrays must to be declared (like the variables) before using it in the code. Declaring an array means creating it by giving it a name (identifier), type and size. In MQL4 we are creating the Arrays like this:int myarray[50];

In the code above we declared one-dimensional array.int keyword indicates that the array is an array of integers.myarray is the name of the array (identifier).[] telling the compiler that we are declaring an array not an integer variable.50 is the size of the array.

We have now a one-dimensional array of 50 integersdouble myarray[5][40];

The line above is the way to declare two-dimensional of seven arrays each of them consisting of 40 doubles.Initializing the Array:Initializing an array (or a variable) means setting its value at the same declaration line.Look at this code which initializes one- dimensional array of 6 integers:

int myarray [6] = {1,4,9,16,25,36};

Example arrays
1-D: [ 3. 1. 4. 1.]
2-D:
[[1 2 3]
[4 5 6]]

3-D:
[[[ 1 2]
[ 3 4]
[ 5 6]]
[[ 7 8]
[ 9 10]
[11 12]]]

116C kh19

2008-11-19T04:23:00.000-08:00

what is computer data?

1.)Some special of data are distinguished.A computer program is a collection of data,which can be interpreted as instructions.

2.)It is useful to distinguish metadata,that is,a description of other data.

3.Relative to today's computer and transmission media,data is imformation converted into binary digital form.

4.)In computer component interconnection and network commucation,data is often distinguished from "control information","control bits."and similar terms to identify the main content of a trasmission unit.

5.)In computer terminology,data often refers to user and configuration files.

6.)Data security measures must be taken when certain types of sensitive information are stored on the computer.

7.)Additionally,data backup strategies are often implemented to prevent accidental or intentional data loss.

=Linear & non linear=

Answer:
Concepts in Complex Systems
Yaneer Bar-Yam

Linear and Nonlinear
The concept of linear relationship suggests that two quantities are proportional to each other: doubling one causes the other to double as well.
Linear relationships are often the first approximation used to describe any relationship, even though there is no unique way to define what a linear relationship is in terms of the underlying nature of the quantities. For example, a linear relationship between the height and weight of a person is different than a linear relationship between the volume and weight of a person. The second relationship makes more sense, but both are linear relationships, and they are, of course, incompatible with each other. Medications, especially for children, are often prescribed in proportion to weight. This is an example of a linear relationship.
Nonlinear relationships, in general, are any relationship which is not linear. What is important in considering nonlinear relationships is that a wider range of possible dependencies is allowed. When there is very little information to determine what the relationship is, assuming a linear relationship is simplest and thus, by Occam's razor, is a reasonable starting point. However, additional information generally reveals the need to use a nonlinear relationship.
Many of the possible nonlinear relationships are still monotonic. This means that they always increase or decrease but not both. Monotonic changes may be smooth or they may be abrupt. For example, a drug may be ineffective up until a certain threshold and then become effective. However, nonlinear relationships can also be non-monotonic. For example, a drug may become progressively more helpful over a certain range, but then may become harmful. Thus the degree of help increases and decreases and this is a non-monotonic, as well as a nonlinear, relationship.
Even when a relationship is monotonic, and the changes in one quantity are smoothly related to the changes in the other quantity a linear relationship is not always the best approximation. It is often useful to generalize to a power law relationship. In a power law relationship every time you double one quantity the other one is multiplied by a number which is not two, but it is always the same number. The dependencies of quantities in many complex systems have been found to be better approximated by power laws than by linear relationships. A power law is a more general form of relationship and for this reason alone it should be a better approximation. However, in many cases there are fundamental reasons for power law behavior in complex systems.

Related concepts: Nonlinear dynamics, power law

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116C Survey KH13

2008-11-12T02:43:00.000-08:00

Structure of an Earth?

Answer:
Geophysics, which studies the physics of the Earth, has led to many significant discoveries about the Earth and its make-up. Seismologic studies of the Earth have uncovered new information about the interior of the Earth that has helped to give credence to plate tectonic theory.

Geophysical studies have revealed that the Earth has several distinct layers. Each of these layers has its own properties. The outermost layer of the Earth is the crust. This comprises the continents and ocean basins. The crust has a variable thickness, being 35-70 km thick in the continents and 5-10 km thick in the ocean basins. The crust is composed mainly of alumino-silicates.
The next layer is the mantle, which is composed mainly of ferro-magnesium silicates. It is about 2900 km thick, and is separated into the upper and lower mantle. This is where most of the internal heat of the Earth is located. Large convective cells in the mantle circulate heat and may drive plate tectonic processes.

The last layer is the core, which is separated into the liquid outer core and the solid inner core. The outer core is 2300 km thick and the inner core is 1200 km thick. The outer core is composed mainly of a nickel-iron alloy, while the inner core is almost entirely composed of iron. Earth's magnetic field is believed to be controlled by the liquid outer core.

The Earth is separated into layers based on mechanical properties in addition to composition. The topmost layer is the lithosphere, which is comprised of the crust and solid portion of the upper mantle. The lithosphere is divided into many plates that move in relation to each other due to tectonic forces. The lithosphere essentially floats atop a semi-liquid layer known as the asthenosphere. This layer allows the solid lithosphere to move around since the asthenosphere is much weaker than the lithosphere.

Structure of an Egg?

Answer:
The egg is a biological structure intended by nature for reproduction. It protects and provides a complete diet for the developing embryo, and serves as the principal source of food for the first few days of the chick's life. The egg is also one of the most nutritious and versatile of human foods.

When the egg is freshly laid, the shell is completely filled. The air cell is formed by contraction of the contents during cooling and by the loss of moisture. A high-quality egg has only a small air cell.
The yolk is well-centered in the albumen and is surrounded by the vitelline membrane, which is colorless. The germinal disc, where fertilization takes place, is attached to the yolk. On opposite sides of the yolk are two, twisted, whitish cord-like objects known as chalazae. Their function is to support the yolk in the center of the albumen. Chalazae may vary in size and density, but do not affect either cooking performance or nutritional value.
A large portion of the albumen is thick. Surrounding the albumen are two shell membranes and the shell itself. The shell contains several thousand pores that permit the egg to "breathe."

116C Survey#1

2008-11-07T02:04:00.000-08:00

A. What is a computer system?

Answer: A complete, working computer. The computer system includes not only the computer, but also any software and peripheral devices that are necessary to make the computer function. Every computer system, for example, requires an operating system.
A computer is a machine that manipulates data according to a list of instructions.

B. What is a computer hardware?

Answer: A computer hardware are consist of motherboard, hard disk, CRT(cathode ray tube), printer, scanner, keyboard, mouse, joy stick, power supply and CPU.