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Journal of Mathematical and Fundamental Sciences
ISSN : 23375760     EISSN : 23385510     DOI : https://doi.org/10.5614/j.math.fund.sci.
Core Subject : Science, Education,
Journal of Mathematical and Fundamental Sciences welcomes full research articles in the area of Mathematics and Natural Sciences from the following subject areas: Astronomy, Chemistry, Earth Sciences (Geodesy, Geology, Geophysics, Oceanography, Meteorology), Life Sciences (Agriculture, Biochemistry, Biology, Health, Medical, Pharmacy), Mathematics, Physics, and Statistics.
Articles 5 Documents
Search results for , issue "Vol. 37 No. 1 (2005)" : 5 Documents clear
Penggunaan Matrix Analytic Technique pada Perhitungan Parameter Kinerja Proses Handoff R. Hadianti; J. Naiborhu; L. Dahliantini
Journal of Mathematical and Fundamental Sciences Vol. 37 No. 1 (2005)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2005.37.1.4

Abstract

This paper discusses performance evaluation of mobile cellular telecommunication system that is related to the handoff process. We focus our discussion to the system with fixed channel assignment and homogeneous traffic. Performance parameters we discuss in this paper are the blocking probability and the dropping probability of handoff signals, and the blocking probability of new originating call signals.The operator of the system usually gives a service priority to handoff signals compare to new originating call signals. In this paper, the priority is given through channels reservation. A number of channels are reserved so that they can be used only for serving handoff signals. The remaining channels are used for serving new originating call signals and if there is an idle channel, it also can be used for serving handoff signals. With this priority, the arrival process and the service process of both types of signals can be modelled as a queueing network that consists of two queueing systems: one system for handoff signals and one system for both signals.The performance of the queueing network is analyzed by deriving the a two-dimensional Markov process. The system of balance equations of the process, which is needed for obtaining the stationary probability distribution of the process, is a large system. We solve this system by applying Matrix Analytic Technique to the two sub-systems simultaneously. The performance parameter values, which are expressed by the stationary probability distribution, are obtained from the solution.
Excitation Mechanism in Laser-Induced Plasma at Atmospheric Air Pressure Jojor Lamsihar Manalu; Koo Hendrik Kurniawan; Tjung Jie Lie
Journal of Mathematical and Fundamental Sciences Vol. 37 No. 1 (2005)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2005.37.1.1

Abstract

A special interferometric technique has been devised on the basis of rainbow refractometry without the use of an additional and delicate amplitude-splitting setup. This new technique was used for the characterization of plasma induced by a Q-switched Nd-YAG laser on zinc samples under atmospheric air pressure. An unmistakable signal of the density jump was detected simultaneously with the observation of the emission front signal. It was proved that the emission front and the front of the shock wave coincided and moved together with time at the initial stage of the secondary plasma expansion. However, at a later stage, the emission front began to separate from and left behind the shock wave front propagating in the surrounding air. With the use of zinc sample, the experimental results showed that the separation of the emission front and shock wave front took place at about 4 mm above sample surface for laser energy of 26 mJ. It was also found that the separation time increased by increasing the power density which further supported shock wave model. Analysis of the data of the shock front movement along with the emission characteristics has led us to the conclusion that models other than the shock wave model, such as the gas breakdown model, should be excluded, at least for a zinc sample, as not satisfactorily explaining the excitation process in the secondary plasma generated at atmospheric air pressure of 760 Torr.
Identifikasi dan Klasifikasi Sinyal EEG terhadap Rangsangan Suara dengan Ekstraksi Wavelet dan Spektral Daya Esmeralda C. Djamal; Harijono A. Tjokronegoro
Journal of Mathematical and Fundamental Sciences Vol. 37 No. 1 (2005)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2005.37.1.5

Abstract

In this research the development of identification and classification technique of three wave components of EEG signal, named alpha, beta and theta, is considered. The technique is combination of wavelet transform and power spectral analysis. Wavelet transform was used to extract the wave components so it reduces the data without loss of the information. The wavelet transform also reduces the aspects of non-stationary of the EEG signal. The EEG's wave classification was based on the appearance of the wave, synchronization between symmetric hemispheres, and the wave energy dominance, in its frequency region. The EEG signals used in this research were obtained from 5 individually-independent subjects after 2.5 minutes sound stimulation. 10 sounds of music and 2 natural sounds were used as sound stimulation in this research. Then, 16 channels of EEG signals, obtained from every individual subject after a sound stimulation, were analyzed. The technique shows that the sound stimulation increases the appearance of the alpha wave by 75% and decreases beta and theta waves by 48% and 56%, respectively. Furthermore, the sound stimulations were used in the research to increase the synchronization balance between symmetric channels by 75%. In addition, this research shows that the signal extraction using wavelet packet provided small deviation and reduced non-stationary aspects, so that it improves the power spectral analysis used in the technique.
Studi Optimasi Parameter Daya RF untuk Penumbuhan Lapisan Tipis Mikrokristal Silikon dengan Metode Hot Wire Cell PECVD S. Amiruddin; L. Usman; Mursal Mursal; T. Winata; Sukirno Sukirno
Journal of Mathematical and Fundamental Sciences Vol. 37 No. 1 (2005)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2005.37.1.2

Abstract

The Hot Wire Cell PECVD method has been developed and successfully applied to grow the hydrogenated amorphous silicon (a-Si:H) thin films with a relatively high conductivity. The a-Si:H thin films were grown on the 7059 corning glass at a filament temperature of 800 oC. Ten percents silane (SiH4) gas diluted in hydrogen (H2) gas was used as gas source. In the hot wire cell PECVD method, reactant gases are decomposed as a result of reaction with a heated filament. The filament was placed parallelly with inlet gas system and outside of electrodes. The characterization results exhibited that the deposition rate increased from 1.02 Å/s to 1.90 Å/s with increasing the rf power from 80 watt to 120 watt. The optical bandgap decreased from 1.65 eV to 1.56 eV with increasing the rf power from 80 watt to 120 watt. The SEM image and the XRD spectrum exhibited the transition of amorphous to microcrystalline silicon at an rf power of 120 watt. The transition of amorphous to microcrystalline was indicated by the reduction of amorphous parts and the appearance of peak diffraction at <111> preferential crystal orientation. The dark and photo conductivities of the obtained μc-Si:H thin films was 6.84x10-6 S cm-1 and 4.16x10-4 S cm-1, respectively.
Datum Geodetik Batas Maritim Indonesia – Singapura: Status dan Permasalahannya Hasanuddin Z. Abidin; K. J. Villanueva; Sobar Sutisna; T. Padmasari
Journal of Mathematical and Fundamental Sciences Vol. 37 No. 1 (2005)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2005.37.1.3

Abstract

Maritime boundary between Indonesia and Singapore in the strait of Singapore has been defined by the territorial sea boundary treaty of 1973.In this treaty, geodetic datum of the geographic coordinates of six boundary points between Indonesia and Singapore are not explicitly stated. This paper investigates the possible datum for these coordinates, namely KERTAU48, KERTAU68, GENUK and SOUTH ASIA, and its impacts on the coordinates and location of boundary points. Related aspects are also discussed. Paper is sum up with some conclusions and recommendations.

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