Metode Incremental Model

   Incremental model adalah model pengembangan sistem pada software engineering berdasarkan requirement software yang dipecah menjadi beberapa fungsi atau bagian sehingga model pengembangannya secara bertahap. dilain pihak ada mengartikan model incremental sebagai  perbaikan dari model waterfall dan sebagai standar pendekatan topdown. Layaknya Model Waterfall, model ini pun juga memiliki tahapan tahapan untuk perancangan perangkat lunaknya, yaitu:

1. Requirement , Requirment adalah proses tahapan awal yang dilakukan pada incremental model adalah penentuan kebutuhan atau analisis kebutuhan.
2. Specification, Specification adalah proses spesifikasi dimana menggunakan analisis kebutuhan sebagai acuannya.
3. Architecture Design, adalah tahap selanjutnya, perancangan software yang terbuka agar dapat diterapkan sistem pembangunan per-bagian pada tahapan selanjutnya.
4. Code setelah melakukan proses desain selanjutnya ada pengkodean.
5. Test merupakan tahap pengujian dalam model ini. 

                                              gambar 1.2 desain pemodelan Incremental

            Tahapan-tahapan tersebut dilakukan secara berurutan. Setiap bagian yang sudah selesai dilakukan testing, dikirim ke pemakai untuk langsung dapat digunakan. Pada incremental model, tiga tahapan awal harus diselesaikan terlebih dahulu sebelum sebelum tahap membangun tiap increment. Untuk mengantisipasi kondisi yang terjadi pada incremental model, diperkenalkan model More Risky Incremental Model. Model ini menerapkan sistem kerja yang paralel. Setelah daftar kebutuhan didapatkan dari pemakai, tim spesifikasi membuat spesifikasi untuk modul pertama. Setelah spesifikasi pertama selesai, tim desain menindak lanjuti. Tim spesifikasi sebelumnya juga langsung membuat spesifikasi untuk model kedua, dan seterusnya. Jadi, tidak harus menunggu modul pertama selesai hingga dikirim ke user.
 
                Beberapa Kelebihan Dari Mode Incremental atara lain :

1. Merupakan model dengan manajemen yang sederhana
2. Pengguna tidak perlu menunggu sampai seluruh sistem dikirim untuk mengambil keuntungan dari sistem tersebut. Increment yang pertama sudah memenuhi persyaratan mereka yang paling kritis, sehingga perangkat lunak dapat segera digunakan.
3. Resiko untuk kegagalan proyek secara keseluruhan lebih rendah. Walaupun masalah masih dapat ditemukan pada beberapa increment. Karena layanan dengan prioritas tertinggi diserahkan pertama dan increment berikutnya diintegrasikan dengannya, sangatlah penting bahwa layanan sistem yang paling penting mengalami pengujian yang ketat. Ini berarti bahwa pengguna akan memiliki kemungkinan kecil untuk memenuhi kegagalan perangkat lunak pada increment sistem yang paling bawah.
4. Nilai penggunaan dapat ditentukan pada setiap increment sehingga fungsionalitas sistem disediakan lebih awal.
5. Memiliki risiko lebih rendah terhadap keseluruhan pengembagan sistem,
6. Prioritas tertinggi pada pelayanan sistem adalah yang paling diuji

      Kelemahannya adalah :

1. kemungkinan tiap bagian tidak dapat diintegrasikan
2. Dapat menjadi build and Fix Model, karena kemampuannya untuk selalu mendapat perubahan selama proses rekayasa berlangsung
3. Harus Open Architecture
4. Mungkin terjadi kesulitan untuk memetakan kebutuhan pengguna ke dalam rencana spesifikasi masing-masing hasil increment. 

sumber : 
http://artikelsayasaja.blogspot.co.id/2011/09/incremental-model-adalah-model.html

MAKALAH COMPUTER NETWORK FOR PPT

DEFINITION OF COMPUTER NETWORKS

     A computer network is a group of interconnected computers. Networks may be classified according to a wide variety of characteristics. The benefit of a computer network are:

-Sharing hardware resources easily and

-Sharing information easily.

    A network is a collection of computers connected to each other. The network allows computers to communicate with each other and share resources and information. The Advanced Research Projects Agency (ARPA) designed"Advanced Research Projects Agency Network“ (ARPANET) for the United States Department of Defense. It was the first computer network in the world in late 1960's and early 1970's.

 

Types of computer networks 

 

1.Local Area Network (LAN)

           Local Area Network (LAN), a privately owned networks within a building or campus-sized to several kilometers. LANs are often used to connect personal computers and workstations in a corporate office or factories to use shared resources (resouce, such as printers) and exchange information. 

2. Metropolitan Area Network (MAN)

     Metropolitan Area Network (MAN) is basically a LAN version is larger and usually use the same technology to the LAN. MAN can include corporate offices are adjacent and can be used for private purposes (private) or public. MAN usually able to support data and voice, and can even be associated with the cable television network. MAN just have a cable or two and do not have the switching element, which serves to regulate the output packets through multiple cables. The existence of switching elements to make the design simpler.

3. Wide Area Network (WAN)

     Wide Area Network (WAN) covers a wide geographical area, often covering a state or continent. WAN consists of a collection of machines intended to run application programs.

4. Wireless Network
    Mobile computers such as notebook computers and Personal Digital Assistant (PDA), a branch of the computer industry's most rapid growth. Many owners of the actual type of computers have desktop machines installed on a LAN or WAN, but it is impossible because a wired connection is made in a car or airplane, so many are interested in having a computer to the network without wires.

5. Internet

    The internet in simple terms is a network of the interlinked computer networking worldwide, which is accessible to the general public. These interconnected computers work by transmitting data through a special type of packet switching which is known as the IP or the internet protocol.

Categories of Networks

 

a. Topology

     Topology is a way to connect one computer  to other computers to form a network. Way that is currently widely

used is the bus, star, and ring.

b. Protocol

   The protocol defines a common set of rules and

signals that computers on the network use to communicate.

Two of the most popular protocols for LANs is called Ethernet and the

IBM token-ring network.
 

c. Architecture

     Networks can be broadly classified as using either a peer-to-peer or client/server architecture. In the preferred system of this network is the use of the program, data and printer together.

Computers on a network are sometimes called nodes. Computers and devices that allocate resources for a network are called servers.

 

Devices to Create a Computer Network

 

1. Network Interface Cards

   A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed     to allow computers to communicate over a computer network. NIC can be identified easily. It has a special port called RJ-45. RJ means Registered Jack. And also a led to indicate a data is being transferred.

2. Repeaters

   A repeater is an electronic device that receives a signal and retransmits it at a higher power level, or to the other side of an obstruction,

so that the signal can cover longer distances without degradation.

3. Hub

   A hub contains multiple ports. When a packet arrives at one port, it is copied to all the ports of the hub for transmission. When the packets are copied, the destination address in the frame

does not change to a broadcast address.

 

4. Router

   a device that forwards data packets between computer

networks, creating an overlay internetwork. A router is

connected to two or more data lines from different

networks. When a data packet comes in one of the lines,

the router reads the address information in the packet to

determine its ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Routers perform the "traffic directing" functions on the Internet.

The Benefits of Computer Network 

 

•  Network helps maintain the information to keep it reliable and up-to-date. Centralized data storage system is managed properly allows many  users access data from a variety of different locations, and limiting access to the data while it is being processed.

•

• Networks help speed up the process of data sharing (data sharing). Transfer data on the network is always faster than other means of data sharing is not the network.

•

 Enabling network-working group communicate more efficiently. Electronic mail and messaging systems are the substance of most of the network, in addition to scheduling systems, project monitoring, online conferencing and groupware, which all help teams work