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29,758 Article Results

Radial Derivative and Radial Inversion for Interpreting 4D Gravity Anomaly Due to Fluids Injection Around Reservoir

10.12928/telkomnika.v16i6.9468
Muhammad; Universitas Gadjah Mada Zuhdi , Sismanto; Universitas Gadjah Mada Sismanto , Ari; Universitas Gadjah Mada Setiawan , Jarot; Universitas Gadjah Mada Setyowiyoto , Adi; Universitas Brawijaya Susilo , Muhammad; Universitas Lampung Sarkowi
The 4D gravity or time lapse gravity has been used many reseracher to identify fluid injection in oil reservoir. The objective of this study is to find the better way in interpreting 4D gravity anomaly due to fluid injection around the reservoir. Radial Derivatives are derivative values of gravity anomalies against horizontal distances in the radial direction. Radial inversion is a two-dimensional inversion of lines with radial directions resulting in a 3-dimension model. Time lapse microgravity research have been performed in “X Oil Field” with amount of 604 data point covering area of 4000m x 5000m. This Radial derivative and Radial inversion have been aplied at an injection well of the X oil field. The yield show that 4D gravity anomaly value due to injection is 0.02 mGal to 0.36 mGal. Radial derivative value in the area is 0 micro Gal/cm to 0,012 mGal/meter. Radial inversion shows radius of fluid front movement is 304 meters to 1120 meters. Radial derivative and Radial inversion have been proven fairly good to identify injected fluid movement in the reservoir.
Volume: 16
Issue: 6
Page: 2855-2863
Publish at: 2018-12-01

Design of Tunable Multiband Hybrid Graphene Metal Antenna in Microwave Regime

10.11591/ijeecs.v12.i3.pp1003-1009
Hussein A. Abdulnabi , Yasin Yousif Al-Aboosi
Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in an hexagonal lattice. It is the basic structural element of many other allotropes of carbon, such as graphite, charcoal, carbon nanotubes and fullerenes. In this paper, a tunable hybrid metal-graphene antenna in the microwave regime is proposed. This antenna composed of the copper patch and four graphene strips. The antenna designs used for the cellular long-term evolution system and the operating frequency bands of 1.8, 2.5, 2.6, and 3.6 GHz, are evaluated to demonstrate the working principle and the performance tradeoffs. Furthermore, the proposed antenna can be tuned by varying applied DC voltage on the graphene which leads to change in the chemical potential of the graphene and hence the surface conductivity and electrical properties are changed. The simulation results reveal that the antenna operates in multi-band where scattering factor S11< -10 dB. In addition, the results show that hybrid metal-graphene frequency reconfigurable antennas can, at the same time, provide a tunable bandwidth and antenna matching.
Volume: 12
Issue: 3
Page: 1003-1009
Publish at: 2018-12-01

Design Mobile App for Increase the Visitor Museum using Gamification Method

10.12928/telkomnika.v16i6.10384
Novian Adi; Universitas Atma Jaya Yogyakarta Prasetyo , Suyoto; Universitas Atma Jaya Yogyakarta Suyoto
The museum's tourism object currently has a low visitor level compared to other tourism objects, even though the museum's function is very important as an enhancer of people's cultural knowledge. Judging from the small level of visitors, it cannot be separated from the effects of the promotion carried out by the museum. From the surveys that have been conducted, museum promotion uses social media more directly to the public, banners, radio, television, blogs and internet social media. In this study, an application that serves to promote museums using gamification methods was designed, this method was chosen because of the many existing promotional techniques, there is still little promotion using game content, therefore the gamification method is expected to encourage the motivation of users to visit the museum. This application will provide convenience to the museum management to promote the museum with media game content without having to spend large development and maintenance costs.
Volume: 16
Issue: 6
Page: 2791-2798
Publish at: 2018-12-01

Analysis Predicted Location of Harmonic Distortion in RF Upconverter Structure

10.12928/telkomnika.v16i6.7628
Sirmayanti; The State Polytechnic of Ujung Pandang Sirmayanti , Mike; Victoria University Faulkner
A new mathematical analysis to predict the magnitude size of the distortion products from the signal up-conversion process output is presented. The signal up-conversion process converts the digital baseband from the analog baseband into a radio frequency signal. When the signal baseband involves frequency offsetting then occurring a number of distortion products which can reduce the dynamic range so it is difficult to meet the spectrum mask requirements within the operating band. This paper will focus on methods of new mathematical analysis using a continuous frequency range and only applies to a single side band tone, with constant amplitude into any value of frequency offsets. The novel contribution to the analysis starts at generating the gate signal and convolution of the gate signal into the reference carrier signal. The results show very close between the simulation results and the calculation of the predicted location of the distortions.
Volume: 16
Issue: 6
Page: 2608-2615
Publish at: 2018-12-01

Electromagnetic Characteristics Measurement of Organic Material Absorber

10.12928/telkomnika.v16i6.9687
Reza; Centre of Electronics Technology Septiawan , Sardjono; Centre of Electronics Technology Trihatmo , Juliati; Centre of Electronics Technology Junde , Dody A.; Center of Polymer Technology Winarto , Arief; Centre of Electronics Technology Rufiyanto , Erik Madyo; Centre of Electronics Technology Putro , Budi; Centre of Electronics Technology Sulistya , Arky; Centre of Electronics Technology Astasari
Electro Magnetic Compatibility (EMC) Chamber requires high performance absorber material to assure the quality of EMC chamber related to Radio Frequency (RF) shielding effectiveness of the corresponding chamber. RF shielding effectiveness is measured following EN 50147-1 testing method. EMC laboratory of BPPT (Indonesian Agency for the Assessment and Application of Technology uses polyurethane absorber material which absorbs the carbon-neoprene mixture to maintain consistent RF performance over a broad frequency band, especially in the frequency range of CISPR 22 radiated emission test between 30 MHz to 6 GHz, limits in CISPR 22 (Information technology equipment-radio disturbance characteristics-limits and methods of measurement). This paper proposes alternative absorber materials based on organic materials: rice husk, coconut husk, cotton and sawn wood crumbs. In the early phase of this research, the frequency under consideration are 900 MHz and 1800 MHz. These frequencies are mostly used by mobile phone devices, therefore at this phase the resulted organic material absorber may be used for alternative mobile phone casing before to be used as absorber material for EMC laboratory in a broader frequency band. The organic materials are produced by mixing them with cement, carbon, and resin. Free space testing method is used in the measurements. Results has shown a mixture of 50% coconut husk with resin absorb the most radiated emission in 900 MHz, while 30% of coconut husk will absorb the most radiated emission in 1800 MHz.
Volume: 16
Issue: 6
Page: 2507-2513
Publish at: 2018-12-01

An Adaptive Internal Model for Load Frequency Control Using Extreme Learning Machine

10.12928/telkomnika.v16i6.11553
Adelhard Beni; Hiroshima University Rehiara , He; Hiroshima University Chongkai , Yutaka; Hiroshima University Sasaki , Naoto; Hiroshima University Yorino , Yoshifumi; Hiroshima University Zoka
As an important part of a power system, a load frequency control has to be prepared with a better controller to ensure internal frequency stability. In this paper, an Internal Model Control (IMC) scheme for a Load Frequency Control (LFC) with an adaptive internal model is proposed. The effectiveness of the IMC control has been tested in a three area power system. Results of the simulation show that the proposed IMC with Extreme Learning Machine (ELM) based adaptive model can accurately cover the power system dynamics. Furthermore, the proposed controller can effectively reduce the frequency and mechanical power deviation under disturbances of the power system.
Volume: 16
Issue: 6
Page: 2879-2887
Publish at: 2018-12-01

Development of a Modular Unit of a Higher Level Framework or Tool for Basic Programming Course Teaching Through E-Learning Mode

10.12928/telkomnika.v16i6.10033
Radhika; VNR Vignana Jyothi Pathi , G.V.; DRS International School Rao , P. Rama; VNR Vignana Jyothi Krishna , P. Bharath; VNR Vignana Jyothi Kumar
This paper reports about the development of a modular unit of a higher level framework or tool whose intended objective is the creation of animated lessons for basic programming (CS1) course in computer science discipline with visual aids. The goal of such lessons is to address the difficulties faced by the novice programmers in CS1 course.This module here after referred to as ‘type writer’allows instructors to render programmes or code snippets in a live typing manner as opposed to their sudden or en-block placement on the presentation area like a Power Point Slide; a commonly used approach in the present day eLearning.This project is planned to be executed in two stages and ‘type writer’ is the outcome of the first stage. This would be combined with another two modules that are planned to be developed in the second stage, to make the complete tool. The entire tool would be developed in Action Script 3.0 language that works on Adobe Flash Platform.
Volume: 16
Issue: 6
Page: 2828-2834
Publish at: 2018-12-01

Design and Analysis of Broadband Elliptical Microstrip Patch Antenna for Wireless Communication

10.12928/telkomnika.v16i6.9246
Ali Khalid; Al Mustansiriyh University Jassim , Raad H.; Al Mustansiriyh University Thaher
In this paper presents the design and manufacture of a new broadband elliptical patch antenna with a microstrip feed line and optimum antenna  parameters. The antenna dimension of (30×21×1.6) mm3 and fabricated on an FR-4 epoxy substrate having relative dielectric constant ε_r=4.3, loss tangent tan (δ) =0.002 and the feed line used has characteristic impedance of 50Ω.The designed antenna has the capability of operating in the bandwidth (6.95 - 30.94) GHz and the gain (6.8) dBi. The antenna performance was modified by inserting a slots in the ground plane to achieve impedance bandwidth (when S11≤ -10dB) and slots to patch to improve the gain. The modified antenna was designed to be used for fifth generation (5G) mobile communication. The simulation results are obtained using CST software.
Volume: 16
Issue: 6
Page: 2492-2499
Publish at: 2018-12-01

Different Multilayer Substrate Approaches to Improve Array Antenna Characteristics for Radar Applications

10.12928/telkomnika.v16i6.10193
N.; National School of Applied Sciences Chater , T.; National School of Applied Sciences Mazri , M.; National School of Applied Sciences Benbrahim
The aim of this paper is to investigate deeply in multi-layer substrate technique as a way of improving the characteristics of patch array antenna for electronic scanning radar application. The basic array antenna consists of 8 patches mounted on a FR-4 substrate and operating at 3GHz frequency. The feeding technique is microstrip technology. This structure has some disadvantages as a poor gain and a narrow bandwidth. In fact, the obtained gain value does not exceed 7 dB which could be explained by the lossy nature of the FR4 substrate. On the other side, the narrow bandwidth is caused by the microstrip limitations. For this reason, the technique of multi-layer substrate is proposed in this paper. Many approaches are investigated and the distance between the layers is studied. The design and simulations of each approach are performed under the tool Advanced Design System of Keysight Company. A comparison between simulation results of all approaches including simulation results of the basic array antenna will be analyzed.
Volume: 16
Issue: 6
Page: 2588-2596
Publish at: 2018-12-01

Detection and Separation of Eeg Artifacts Using Wavelet Transform

10.11591/ijict.v7i3.pp149-156
R. Suresh Kumar , P. Manimegalai
Bio-medical signal processing is one of the most important techniques of multichannel sensor network and it has a substantial concentration in medical application. However, the real-time and recorded signals in multisensory instruments contains different and huge amount of noise, and great work has been completed in developing most favorable structures for estimating the signal source from the noisy signal in multichannel observations. Methods have been developed to obtain the optimal linear estimation of the output signal through the Wide-Sense-Stationary (WSS) process with the help of time-invariant filters. In this process, the input signal and the noise signal are assumed to achieve the linear output signal. During the process, the non-stationary signals arise in the bio-medical signal processing in addition to it there is no effective structure to deal with them. Wavelets transform has been proved to be the efficient tool for handling the non-stationary signals, but wavelet provide any possible way to approach multichannel signal processing. Based on the basic structure of linear estimation of non-stationary multichannel data and statistical models of spatial signal coherence acquire through the wavelet transform in multichannel estimation. The above methods can be used for Electroencephalography (EEG) signal denoising through the original signal and then implement the noise reduction technique to evaluate their performance such as SNR, MSE and computation time.
Volume: 7
Issue: 3
Page: 149-156
Publish at: 2018-12-01

Voltage Regulation of Boost Converter using Observer based Sliding Mode Controller

10.12928/telkomnika.v16i6.11558
Ramadhani Kurniawan; Brawijaya University Subroto , Sapriesty Nainy; Brawijaya University Sari , Zainul; Brawijaya University Abidin , Kuo Lung; National Taiwan University Lian
This study dealt with output voltage regulation of boost converter using observer based sliding mode controller comprises of adaptive PI sliding surface. Observer was designed to estimate the inductor current value, such that no sensor was required as a feedback. Adaptive PI sliding surface was constructed from the difference between estimated inductor current and its reference value. The stability of proposed method was ensured by using Lyapunov direct method. To test the system performance, numerical simulation was conducted. The result indicated that the integral absolute error value of proposed method was 0.19, which was 7 times less than sliding mode with PI sliding surface. Consequently, the proposed method was able to estimate accurately the inductor value, track the reference voltage perfectly, and show its robustness against parameter variations.
Volume: 16
Issue: 6
Page: 2896-2904
Publish at: 2018-12-01

Design of Quasi-Elliptic Bandpass Filter for Substrate Integrated Waveguide (SIW) Using Cross Coupling Technique

10.11591/ijeecs.v12.i3.pp1366-1372
Muhajir Mustapa , ZahrilAdha Zakaria , Noor Azwan Shairi
This paper proposes a quasi-elliptic band pass filter in substrate integrated waveguide (SIW) by using cross coupling technique to produce transmission zeros (TZs) at both side. Finally, a fourth pole SIW quasi-elliptic filter at 5.75 GHz is designed in single layer substrate. Simulation results show that the filter has a center frequency of 5.75 GHz with the bandwidth of 100 MHz. The minimum insertion loss in the passband is 0.3 dB, and the return loss is better than 20 dB. Due to the TZs, the SIW filter has rapid transition performance at both lower and upper sidebands, good selectivity is achieved, while the SIW filter presents a very compact implementation and goodspurious rejection.
Volume: 12
Issue: 3
Page: 1366-1372
Publish at: 2018-12-01

Performance Enhancement of Wideband Reflectarray Antennas Embedded on Paper Substrate Materials

10.12928/telkomnika.v16i6.9595
M. Y.; Universiti Tun Hussein Onn Malaysia (UTHM) Ismail , H. I.; Universiti Tun Hussein Onn Malaysia (UTHM) Malik
This research presents an innovative solution to address the bandwidth limitation of microstrip reflectarray antennas. Organic substrate materials with controlled compositions have been characterized to be employed as substrate materials for microstrip reflectarrays. The three proposed materials show low dielectric permittivity values of 1.81, 1.64 and 1.84 along with loss tangents of 0.053, 0.047 and 0.057 respectively. The proposed substrate materials have been verified by modelling reflectarray unit elements in CST MWS and measured using a waveguide simulator technique. The comparison between measured and simulated results show a good agreement with promising broadband performance of 312, 340 and 207 MHz for S1, S2 and S3 substrate materials respectively.
Volume: 16
Issue: 6
Page: 2616-2621
Publish at: 2018-12-01

Accelerating Compression Time of the standard JPEG by Employing The Quantized YCbCr Color Space Algorithm

10.11591/ijece.v8i6.pp4343-4351
Trini Saptariani , Sarifudin Madenda , Ernastuti Ernastuti , Widya Silfianti
In this paper, we propose a quantized YCbCr color space (QYCbCr) technique which is employed in standard JPEG. The objective of this work is to accelerate computational time of the standard JPEG image compression algorithm. This is a development of the standard JPEG which is named QYCBCr algorithm. It merges two processes i.e., YCbCr color space conversion and Q quantization in which in the standar JPEG they were performed separately. The merger forms a new single integrated process of color conversion which is employed prior to DCT process by subsequently eliminating the quantization process. The equation formula of QYCbCr color coversion is built based on the chrominance and luminance properties of the human visual system which derived from quatization matrices. Experiment results performed on images of different sizes show that the computational running time of QYCbCr algorithm gives 4 up to 8 times faster than JPEG standard, and also provides higher compression ratio and better image quality.
Volume: 8
Issue: 6
Page: 4343-4351
Publish at: 2018-12-01

Secure Code Generation for Multi-Level Mutual Authentication

10.12928/telkomnika.v16i6.10437
Gregor Alexander; Al-Mustansiriyah University Aramice , Jaafar Qassim; Al-Mustansiriyah University Kadhim
Any secured system requires one or more logging policies to make that system safe. Static passwords alone cannot be furthermore enough for securing systems, even with strong passwords illegal intrusions occur or it suffers the risk of forgotten. Authentication using many levels (factors) might complicate the steps when intruders try to reach system resources. Any person to be authorized for logging-in a secured system must provide some predefined data or present some entities that identify his/her authority. Predefined information between the client and the system help to get more secure level of logging-in. In this paper, the user that aims to log-in to a secured system must provide a recognized RFID card with a mobile number, which is available in the secured systems database, then the secured system with a simple algorithm generates a One-Time Password that is sent via GSM Arduino compatible shield to the user announcing him/her as an authorized person.
Volume: 16
Issue: 6
Page: 2643-2650
Publish at: 2018-12-01
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