Judul: Autentikasi Berbasis LDAP Untuk Interkoneksi Server VoIP Menggunakan Codec G.722 dan GSM.
Abstrak: VoIP merupakan salah satu layanan telekomunikasi berbasis IP yang berkembang dengan cepat. VoIP memiliki beberapa protokol signaling yaitu H.323, SIP, dan IAX. QoS dapat mempengaruhi kualitas suara. Parameter QoS yang diukur yaitu delay, jitter, dan packet loss. Kualitas suara dapat diukur dengan menghitung nilai R factor. Dalam penelitian ini komunikasi VoIP dibangun dalam server yang sama dan antarserver. Penyimpanan data user pada VoIP dilakukan dengan melakukan integrasi dengan LDAP. Pengujian dilakukan dengan menganalisa QoS menggunakan codec yang sama dan codec yang berbeda. Hasil pengujian menunjukan codec GSM mendapat nilai QoS terbaik yaitu jitter 16.92 ms, delay 40.12 ms, dan packet loss 0.19% serta mendapat nilai R factor sebesar 92 dan pada codec G.722 mendapat nilai jitter 19.48 ms, delay 40.14 ms, dan packet loss 0.22 % serta mendapat nilai R factor sebesar 91.
Keyword: client, codec, interkoneksi, QoS, server, VoIP

Judul: Integrasi Infrastruktur Teknologi VoIP pada Smartphone (Android) dan PABX pada Lingkungan Jaringan IPB
Abstrak: Voice over Internet Protocol (VoIP) has become a widely used communication media. The increase of internet and number of smartphone users has become important factors that supports the broader use of VoIP technology. While on the other hand the number users of Public Switched Telephone Network (PSTN) is still quite a lot, even in office buildings are usually equipped with a device Private Automatic Branch eXchange (PABX). The purposes of this research is to interconnect VoIP networks and PABX network on IPB computer network and also develop a VoIP client application for Android. In this research the use of Android smartphone is limited on Wi-Fi network. The method used in this study consisted of: study of the network topology of IPB, installation of VoIP server, interconnection between VoIP network and PABX, interconnection VoIP server and server of Lightweight Directory Access Protocol, and development of VoIP client application for smartphones. Communication between VoIP and PABX on the IPB computer network has been established, and a VoIP client application for smartphones has been developed. The values of delay, jitter and packet loss are 43.74 ms, 14.76 ms, and 0.81% respectively and the value of Mean Opinion Score (MOS) is between 4 and 4.3. It can be concluded that the quality of VoIP networks in IPB is good.
Keyword: 

Judul: Sintesis Magnetit dari Filtrat Hasil Destruksi Tailing Pasir Timah Pulau Bangka secara Hidrotermal
Abstrak: The iron content in the filtrate of tin tailings sand destruction (FTTSD) of Bangka Island is potential as raw material for synthesis of magnetite. Very low acidity and the presence of Ti in FTTSD may interfere the synthesis process. The study began by examine the effect of Ti in the magnetite synthesis and determined the Fe and Ti contents in the FTTSD. NaOH and urea were added to FTTSD to raise the pH for syntesis. The results showed that the mole ratio of Ti/Fe of less than 0.125 did not interfere the magnetite synthesis, therefore the mole ratio of Ti/Fe 0.121 could be used as raw material for the synthesis. The addition of NaOH in FTTSD did not produce magnetite. Replacement of NaOH with urea produced magnetite crystals with an average size of 64.5 nm according to Scherrer equation.
Keyword: