Perbandingan Perhitungan Trafik Jam Sibuk CDMA 2000 1x Pada BTS Inner City Dan BTS Outer City Dengan Mempergunakan Metode ADPH, TCBH, FDMH Dan FDMP

Cellular communication system is a wireless communication system where the subscriber can move within a wide network coverage. Code Division Multiple Access (CDMA) is a multiuser access technology that is each user uses a unique code contained in the access channel in the system. Calculation and determination of peak hours can be done by several methods such as: Average Daily Peak Hour (ADPH), Time Consistent Busy Hour (TCBH), Fixed Daily Measurement Hour (FDMH), Fixed Daily Measurement Period (FDMP). The effectiveness of the channel should be determined by occupancy both at inner city territory and outer city  territory location. Using design Erlang (Erl) for supply channel at Base Transceiver Station (BTS) that provided, BTS has a design Erlang of 369,83 Erl at inner city and it has a design Erlang of 241,8 Erl at outer city. Peak hour on the inner city occurred at 12:00 to 15:00, whereas the outer city of peak hour occurred at 18:00 to 21:00. Effectiveness value that determined by operator are : <20% = low occupancy (not effective), 21% to 69% = normal occupancy (effective), and > 70% = high occupancy (very effective). In this case occupancy values obtained in each method is between 21% to 69% which means effectiv

Pulse Electrochemical Driven Rapid Layer-by-Layer Assembly of Polydopamine and Hydroxyapatite Nanofilms via Alternative Redox <i>in Situ</i> Synthesis for Bone Regeneration

Polydopamine (PDA) is an important candidate material for the surface modification of biomedical devices because of its good adhesiveness and biocompatibility. However, PDA nanofilms lack osteoinductivity, limiting their applications in bone tissue engineering. Hydroxyapatite nanoparticles (HA-NPs) are the major component of natural bone, which can be used to effectively enhance the osteoinductivity of PDA nanofilms. Herein, we developed a pulse electrochemical driven layer-by-layer (PED-LbL) assembly process to rapidly deposit HA-NPs and PDA (HA-PDA) multilayer nanofilms. In this process, PDA and HA-NPs are <i>in situ</i> synthesized in two sequential oxidative and reductive pulses in each electrochemical deposition cycle and alternately deposited on the substrate surfaces. PDA assists the <i>in situ</i> synthesis of HA-NPs by working as a template, which avoids the noncontrollable HA nucleation and aggregation. The HA-PDA multilayer nanofilms serve as a tunable reservoir to deliver bone morphogenetic protein-2 and exhibit high osteoinductivity both <i>in vitro</i> and <i>in vivo</i>. This PED-LbL assembly process breaks the limitation of traditional LbL assembly, allowing not only the rapid assembly of oppositely charged polyelectrolytes but also the <i>in situ</i> synthesis of organic/inorganic NPs that are uniformly incorporated in the nanofilm. It has broad applications in the preparation of versatile surface coatings on various biomedical devices