COAXIAL CABLE

Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who patented the design in 1880.^[1]

Coaxial cable is used as a transmission line for radio frequency signals. Its applications include feedlines connecting radio transmitters and receivers with their antennas, computer network (Internet) connections, and distributing cable televisionsignals. One advantage of coax over other types of radio transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. Coaxial cable also provides protection of the signal from external electromagnetic interference.

Coaxial cable differs from other shielded cable used for carrying lower frequency signals, such as audio signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a radio frequency transmission line.

TWISTED PAIR CABLE

In balanced pair operation, the two wires carry equal and opposite signals and the destination detects the difference between the two. This is known asdifferential mode transmission. Noise sources introduce signals into the wires by coupling of electric or magnetic fields and tend to couple to both wires equally. The noise thus produces a common-mode signal which is cancelled at the receiver when the difference signal is taken. This method starts to fail when the noise source is close to the signal wires; the closer wire will couple with the noise more strongly and the common-mode rejection of the receiver will fail to eliminate it. This problem is especially apparent in telecommunication cables where pairs in the same cable lie next to each other for many miles. One pair can induce crosstalk in another and it is additive along the length of the cable. Twisting the pairs counters this effect as on each half twist the wire nearest to the noise-source is exchanged. Providing the interfering source remains uniform, or nearly so, over the distance of a single twist, the induced noise will remain common-mode. Differential signaling also reduces electromagnetic radiation from the cable, along with the associated attenuation allowing for greater distance between exchanges.

The twist rate (also called pitch of the twist, usually defined in twists per meter) makes up part of the specification for a given type of cable. Where nearby pairs have equal twist rates, the same conductors of the different pairs may repeatedly lie next to each other, partially undoing the benefits of differential mode. For this reason it is commonly specified that, at least for cables containing small numbers of pairs, the twist rates must differ.^[1]

In contrast to FTP (foiled twisted pair) and STP (shielded twisted pair) cabling, UTP (unshielded twisted pair) cable is not surrounded by any shielding. It is the primary wire type for telephone usage and is very common for computer networking, especially as patch cables or temporary network connections due to the high flexibility of the cables.

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Carta Organisasi Kelas

Tenaga Pengajar

BAHASA MELAYU-PUAN ZALEHA ABDUL SAMAD

BAHASA INGGERIS-MADAM FATHIAH RASHID

MATEMATIK-ENCIK HASSAN PUTEH

SAINS-PUAN ZALEHA SAIIN

AGAMA ISLAM-PUAN HAJAH NOREHA JOHDI

SEJARAH-PUAN SARIMAH SHUIB

PRINSIP PERAKAUNAN-PUAN ZARINA AHMAD

I.C.T-ENCIK BASORI ABDUL RAHMAN&PUAN NURUL AMALINA

MATEMATIK TAMBAHAN-ENCIK CHE SALIM ABU BAKAR

JADUAL WAKTU KELAS

ISNIN

08:15-09:25 Matematik Tambahan

09:25-1035 Bahasa Melayu

10:35-10:55 Rehat

10:55-11:30 Sains

11:30-12:05 Matematik

12:05-13:15 Prinsip Perakaunan

SELASA

07:35-08:10 Matematik

08:10-08:45 PJPK

08:45-09:20 PSK

09:20-10:30 Prinsip Perakaunan

10:30-10:50 Rehat

10:50-11:25 Pendidikan Agama Islam

11:25-12:35 Sains

12:35-13:10 Matematik Tambahan

13:10-13:45 Bahasa Inggeris

RABU

07:35-08:10 PSK

08:10-09:20 ICT

09:20-10:30 Bahasa Inggeris

10:30-10:50 Rehat

10:50-11:25 Matematik Tambahan

11:25-12:35 Sains

12:35-13:45 Matematik

KHAMIS

07:35-08:10 Matematik Tambahan

08:10-09:20 ICT

09:20-10:30 Bahasa Melayu

10:30-10:50 Rehat

10:50-12:00 Sejarah

12:00-13:10 Pendidikan Agama Islam

13:10-13:45 Bahasa Inggeris

JUMAAT

08:00-08:35 Sejarah

08:35-09:10 Bahasa Inggeris

09:10-09:45 PJPK

09:45-10:20 Matematik

10:20-10:40 Rehat

10:40-11:15 Pendidikan Agama Islam

11:15-12:25 Bahasa Melayu

Aktiviti Kelas

22 Jun 2011 : Pc Assembly (ICT)

Aktiviti Kelas

20 Jun 2011 : Kuiz Prinsip Akaun

Aktiviti Kelas

22 Januari 2011: Mengadakan Gotong-royong menghias kelas.

Jadual Harian

5 USM KELASKU ~

-UMMU SUHAINA ABDUL RAHMAN

-MIMIE ROZMIZA ROZMAN

-EVA NATASHA AHMAD

-CHAN KAH MUN

-TAN SU YING

-ENNI EFAFIQA

-HIDAYATUL UMAIRAH

-NUR HIDAYAH

-FARAH NINI

-NURUL HAZIRAH

-CHUAH CHE YIN

-LIM KAI LOON

-NG JUN HAO

-SHU PHOOI SEE

-YEAP SHI HUI

-SITI SHUHADA ANUM

-YOGARAJAN

-YASOTARAN

-SATISWARAN

-WAN NURUL ASYIKIN

-NURUL KHATIJAH

-REMECCA

-UHUNESHWARY

-LEE HWANG GAO

-TEH WEI JUN

-AZMAN

-NAZRUN NAIM

-FADHULAH

-ISZWAN

-IZZUDDIN

-HARITH AQIF

Hackers Target Malaysian Government Sites

A number of Malaysian government Web sites fell prey to cyber attacks Wednesday night in a coordinated effort possibly organized by members of the clandestine Web group, Anonymous.

Ninety-one Web sites were attacked starting at 11:30pm local time, the Malaysian Communications and Multimedia Commission told Bloomberg. Seventy-six have since come back online.

Earlier this week, an image from Anonymous circulated, calling on supporters to attack malaysia.gov.my on June 15 at 7:30pm GMT.

In a YouTube video (below) posted on June 14, Anonymous criticized Malaysian government officials for their censorship of the Web.

"We have seen the censorship taken by the Malaysian government, blocking sites like The Pirate Bay, and WikiLeaks," according to a voice in the video, which was set to music from the movie Inception. "Malaysia is one of the world's strictest governments, even blocking out movies, and television shows. These acts of censorship are inexcusable. You are taking away a basic human right. The Internet is here for freedom, without fear of government interference."

The video went on to warn Malaysian officials that "this is a sign, a warning, and an opportunity to listen to ideas above your own."

"Now we will wash your corruption away so be prepared. Take this as a favour," the group concluded.

Malaysia, however, has not been mentioned on the AnonOps Twitter feed or blog. Most recently, those sites have named Federal Reserve chairman Ben Bernanke as the next Anonymous target. Anonymous, however, is a rather splintered group. If you say you are a member of Anonymous, you are a member of Anonymous, making the group difficult to track. Bloomberg reports that many of the Malaysia attacks came from unidentified local hackers, who set up a blog to share updates.

The fractured nature of Anonymous, however, hasn't stopped some officials from crackdowns. Members of the group were arrested in Spain and Turkey this week over distributed denial of service (DDoS) attacks similar to the ones that affected the Malaysia sites.

Ruby (programming language)

Ruby is a dynamic, reflective, general purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto. It was influenced primarily by Perl, Smalltalk, Eiffel, and Lisp.

Ruby supports multiple programming paradigms, including functional, object oriented, imperative and reflective. It also has a dynamic type system and automatic memory management; it is therefore similar in varying respects to Python, Perl, Lisp, Dylan, Pike, and CLU.

The standard 1.8.7 implementation is written in C, as a single-pass interpreted language. There is currently no specification of the Ruby language, so the original implementation is considered to be the de facto reference. As of 2010^[update], there are a number of complete or upcoming alternative implementations of the Ruby language, including YARV, JRuby, Rubinius, IronRuby, MacRuby, and HotRuby. Each takes a different approach, with IronRuby, JRuby and MacRuby providing just-in-time compilation and MacRuby also providing ahead-of-time compilation. The official 1.9 branch uses YARV, as will 2.0 (development), and will eventually supersede the slower Ruby MRI.

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems (which is now a subsidiary of Oracle Corporation) and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. Java applications are typically compiled to bytecode (class file) that can run on any Java Virtual Machine (JVM) regardless of computer architecture. Java is a general-purpose, concurrent, class-based, object-oriented language that is specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere". Java is currently one of the most popular programming languages in use, and is widely used from application software to web applications.^[9][10]

The original and reference implementation Java compilers, virtual machines, and class libraries were developed by Sun from 1995. As of May 2007, in compliance with the specifications of the Java Community Process, Sun relicensed most of its Java technologies under the GNU General Public License. Others have also developed alternative implementations of these Sun technologies, such as the GNU Compiler for Java, GNU Classpath, and Dalvik.

Programming Language Generations

- In the computer industry, these abbreviations are widely used to represent major steps or "generations" in the evolution of programming languages.
1GL or first-generation language was (and still is) machine language or the level of instructions and data that the processor is actually given to work on (which in conventional computers is a string of 0s and 1s).
2GL or second-generation language is assembler (sometimes called "assembly") language. A typical 2GL instruction looks like this: ADD 12,8
An assembler converts the assembler language statements into machine language.
3GL or third-generation language is a "high-level" programming language, such as PL/I, C, or Java. Java language statements look like this: public boolean handleEvent (Event evt) {
switch (evt.id) {
case Event.ACTION_EVENT: {
if ("Try me" .equald(evt.arg)) {
A compiler converts the statements of a specific high-level programming language into machine language. (In the case of Java, the output is called bytecode, which is converted into appropriate machine language by a Java virtual machine that runs as part of an operating system platform.) A 3GL language requires a considerable amount of programming knowledge.
4GL or fourth-generation language is designed to be closer to natural language than a 3GL language. Languages for accessing databases are often described as 4GLs. A 4GL language statement might look like this: EXTRACT ALL CUSTOMERS WHERE "PREVIOUS PURCHASES" TOTAL MORE THAN $1000
5GL or fifth-generation language is programming that uses a visual or graphical development interface to create source language that is usually compiled with a 3GL or 4GL language compiler. Microsoft, Borland, IBM, and other companies make 5GL visual programming products for developing applications in Java, for example. Visual programming allows you to easily envision object-oriented programming class hierarchies and drag icons to assemble program components.

Programming Language

A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine, to express algorithms precisely, or as a mode of human communication.
The earliest programming languages predate the invention of the computer, and were used to direct the behavior of machines such as Jacquard looms and player pianos. Thousands of different programming languages have been created, mainly in the computer field, with many more being created every year. Most programming languages describe computation in an imperative style, i.e., as a sequence of commands, although some languages, such as those that support functional programming or logic programming, use alternative forms of description.
A programming language is usually split into the two components of syntax (form) and semantics (meaning) and many programming languages have some kind of written specification of their syntax and/or semantics. Some languages are defined by a specification document, for example, the C programming language is specified by an ISO Standard, while other languages, such as Perl, have a dominant implementation that is used as a reference.