Articles
33
Documents
Reconstruction of Planar Multilayered Structures using Multiplicative-Regularized Contrast Source Inversion

TELKOMNIKA Telecommunication, Computing, Electronics and Control Vol 11, No 3: September 2013
Publisher : Universitas Ahmad Dahlan

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Abstract

There is an increasing interest to have an access to hidden objects without making any destructive action. Such non-destructive method is able to give a picture of the inner part of the structure by measuring some external entities. The problem of reconstructing planar multilayered structures based on given scattering data is an inverse problem. Inverse problems are ill-posed, beside matrix inversion tools, a regularization procedure must be applied additionally. Multiplicative regularization was considered as an appropriate penalty method to solve this problem. The Gauss-Newton inversion method as an optimization procedure was used to find the permittivity values, which minimized some cost functions. Several dielectric layers with different thickness and profiles were observed.Some layers needed more discretization elements and more iteration steps to give the correct profiles.

DESIGN OF TIRE PRESSURE MONITORING SYSTEM USING A PRESSURE SENSOR BASE

SINERGI Vol 23, No 1 (2019)
Publisher : Universitas Mercu Buana

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Abstract

Currently, the Tire Pressure Monitoring System (TPMS) only monitors the condition of a tire pressure. However, there are no particular reactions taking place after the value of its tire pressure is discovered. In fact, the value of a tire pressure determines driving comfort and safety Therefore, this research proposed a method to integrate a TPMS and a Pressure Sensor Base (PSB) with a particular reaction required to fulfill tires automatically. The proposed TPMS has an electronic device unit directly attached to a tire’s valve. This unit includes pressure sensors, microcontrollers, Bluetooth transmitters and batteries. An alert system is generated whenever tire pressure exceeds the maximum or minimum safe pressure level. Moreover, if the pressure measured is below the lowest level of the desired pressure, it will automatically activate the compressor. Several experiments have been carried out to analyze the proposed system. The integrated TPMS has proven to be able to be an alternative tool for the automotive sector to keep maintaining the tires and to improve a driving comfort and safety.

PERANCANGAN TRANSISI KOAXIAL KE WAVEGUIDE WG8

Jurnal Teknik Elektro Vol 4, No 2 (2013)
Publisher : Jurnal Teknik Elektro

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Abstract

Waveguide adalah struktur yang membimbing gelombang, seperti gelombang elektromagnetik atau gelombang suara. Ada berbagai jenis Waveguide untuk setiap jenis gelombang. Yang asli dan paling umum, artinya adalah pipa logam kosong digunakan untuk tujuan ini. Waveguides berbeda dalam geometri yang dapat membatasi energi dalam satu dimensi seperti di lempengan waveguides atau dua dimensi seperti dalam serat atau saluran waveguides. Selain itu, waveguides berbeda diperlukan untuk memandu frekuensi yang berbeda: membimbing serat optik laser (frekuensi tinggi) tidak akan memandu gelombang mikro (yang memiliki frekuensi yang jauh lebih rendah). Kata kunci: Waveguide, transisi koaxial, serat optik laserAbstract - Waveguide is a structure that guides the waves, like electromagnetic waves or sound

Design of Chebychev’s Low Pass Filters Using Nonuniform Transmission Lines

Journal of ICT Research and Applications Vol 9, No 3 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

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Abstract

Transmission lines are utilized in many applications to convey energy as well as information. Nonuniform transmission lines (NTLs) are obtained through variation of the characteristic quantities along the axial direction. Such NTLs can be used to design network elements, like matching circuits, delay equalizers, filters, VLSI interconnections, etc. In this work, NTLs were analyzed with a numerical method based on the implementation of method of moment. In order to approximate the voltage and current distribution along the transmission line, a sum of basis functions with unknown amplitudes was introduced. As basis function, a constant function was used. In this work, we observed several cases such as lossless and lossy uniform transmission lines with matching and arbitrary load. These cases verified the algorithm developed in this work. The second example consists of nonuniform transmission lines in the form of abruptly changing transmission lines. This structure was used to design a Chebychev’s low pass filter. The calculated reflection and transmission factors of the filters showed some coincidences with the measurements.

PERANCANGAN TRANSISI KOAXIAL KEWAVEGUIDE WG8

Jurnal Teknologi Elektro Vol 4, No 2 (2013)
Publisher : Universitas Mercu Buana

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Abstract

Waveguide adalah struktur yang membimbing gelombang, seperti gelombang elektromagnetik atau gelombang suara. Ada berbagai jenis Waveguide untuk setiap jenis gelombang. Yang asli dan paling umum, artinya adalah pipa logam kosong digunakan untuk tujuan ini. Waveguides berbeda dalam geometri yang dapat membatasi energi dalam satu dimensi seperti di lempengan waveguides atau dua dimensi seperti dalam serat atau saluran waveguides. Selain itu, waveguides berbeda diperlukan untuk memandu frekuensi yang berbeda: membimbing serat optik laser (frekuensi tinggi) tidak akan memandu gelombang mikro (yang memiliki frekuensi yang jauh lebih rendah).Kata kunci: Waveguide, transisi koaxial, serat optik laser

Degradation of Shielding Performance of Metallic Sheet due to Aperture Configuration and Dimension at 2.4 GHz

Jurnal Elektronika dan Telekomunikasi Vol 18, No 1 (2018)
Publisher : Indonesian Institute of Sciences

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Abstract

The increasing demand on wireless connectivity has opened new and modern communication systems. Many wireless systems, for example Wireless Fidelity (Wi-Fi), Bluetooth, ZigBee, share the unlicensed frequency region around 2.4 GHz. Due to intensive application of Wi-Fi systems, there are certain disturbance potentials observed. The Wi-Fi signals cause interference to ZigBee networks which are used for smart grid applications. In this work, the shielding effectiveness of a metallic enclosure with several apertures is studied. Based on analytical expression from the literature, the shielding effectiveness by varying the sheet thickness, number of apertures, and aperture patterns is calculated. Several measurements of Received Signal Strength Indicator (RSSI) are carried out. The measurements are conducted on a shielded room to isolate the measurement from other unknown signal sources. The calculation and measurement of shielding effectiveness confirmed that more apertures on a shielding sheet will reduce the Shielding Effectiveness (SE). SE for one aperture for the case sheet thickness 0.7 mm and diameter of 12 mm reduce from 46.28 dB to 14.24 dB for 6 apertures. Bigger aperture diameters will also degrade the SE from 46.28 dB to 5.27 dB for aperture diameter 24 mm. The same condition can be concluded for the thickness 1.4 mm for aperture diameter of 12 mm. However a slightly different measurement results are obtained for the thickness 1.4 mm and aperture diameter of 24 mm. The thickness plays a significant role to attenuate the wave, so that SE is bigger than the calculated one.

WHATSAPP FORENSICS PADA ANDROID SMARTPHONE : A SURVEY

SINERGI Vol 20, No 3 (2016)
Publisher : Universitas Mercu Buana

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Abstract

Salah satu applikasi jejaring sosial yang sangat populer saat ini adalah WhatsApp. Hampir seluruh pengguna smartphone menggunakan applikasi ini sebagai media komunikasi. Berbagai macam perkembangan atau fitur baru telah banyak ditambahkan pengembang sebagai fasilitas yang dapat memanjakan para pengguna. Peranan sistem keamanan tentunya sangat penting untuk menunjang keamanan privasi para pengguna agar kerahasiaan tetap terjaga. Beberapa peneliti telah banyak melakukan experimen mobile forensics untuk mendapatkan berbagai informasi dari para pengguna WhatsApp. Pada paper ini membahas survey berbagai metoda dari berbagai para peneliti WhatsApp forensics. Dalam sebuah proses mobile metoda yang digunakan dalam proses forensics antara lain menggunakan internet protocol dan live memory. Untuk proses mobile forensics khususnya pada applikasi WhatsApp dapat dilakukan dengan menggunakan metoda tersebut untuk memperoleh data informasi yang dibutuhkan.

Hierarchical Gaussian Scale-Space on Androgenic Hair Pattern Recognition

TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 1: March 2017
Publisher : Universitas Ahmad Dahlan

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Abstract

Androgenic hair pattern stated to be the new biometric trait since 2014. The research to improve the performance of androgenic hair pattern recognition system has begun to be developed due to the problems that occurred when other apparent biometric trait such as face is hidden from sight. The recognition system was built with hierarchical Gaussian scale-space using 4 octaves and 3 levels in each octave. The system also implemented the equalization process to adjust image’s intensity by using histogram equalization. We analyzed 400 images of androgenic hair in the database that were analyzed using 2-fold and 10-fold cross validation and Euclidean distance to classify it. The experimental results showed that our proposed method gave better performance compared to previous work that used Haar wavelet transformation and principal component analysis as the main method. The best recognition precision was 94.23 % obtained from the base octave with the third level using histogram equalization and 10-fold cross validation.   

WHATSAPP FORENSICS PADA ANDROID SMARTPHONE : A SURVEY

SINERGI Vol 20, No 3 (2016)
Publisher : Universitas Mercu Buana

Show Abstract | Original Source | Check in Google Scholar

Abstract

Salah satu applikasi jejaring sosial yang sangat populer saat ini adalah WhatsApp. Hampir seluruh pengguna smartphone menggunakan applikasi ini sebagai media komunikasi. Berbagai macam perkembangan atau fitur baru telah banyak ditambahkan pengembang sebagai fasilitas yang dapat memanjakan para pengguna. Peranan sistem keamanan tentunya sangat penting untuk menunjang keamanan privasi para pengguna agar kerahasiaan tetap terjaga. Beberapa peneliti telah banyak melakukan experimen mobile forensics untuk mendapatkan berbagai informasi dari para pengguna WhatsApp. Pada paper ini membahas survey berbagai metoda dari berbagai para peneliti WhatsApp forensics. Dalam sebuah proses mobile metoda yang digunakan dalam proses forensics antara lain menggunakan internet protocol dan live memory. Untuk proses mobile forensics khususnya pada applikasi WhatsApp dapat dilakukan dengan menggunakan metoda tersebut untuk memperoleh data informasi yang dibutuhkan.

DESIGN OF TIRE PRESSURE MONITORING SYSTEM USING A PRESSURE SENSOR BASE

SINERGI Vol 23, No 1 (2019)
Publisher : Universitas Mercu Buana

Show Abstract | Original Source | Check in Google Scholar

Abstract

Currently, the Tire Pressure Monitoring System (TPMS) only monitors the condition of a tire pressure. However, there are no particular reactions taking place after the value of its tire pressure is discovered. In fact, the value of a tire pressure determines driving comfort and safety Therefore, this research proposed a method to integrate a TPMS and a Pressure Sensor Base (PSB) with a particular reaction required to fulfill tires automatically. The proposed TPMS has an electronic device unit directly attached to a tire’s valve. This unit includes pressure sensors, microcontrollers, Bluetooth transmitters and batteries. An alert system is generated whenever tire pressure exceeds the maximum or minimum safe pressure level. Moreover, if the pressure measured is below the lowest level of the desired pressure, it will automatically activate the compressor. Several experiments have been carried out to analyze the proposed system. The integrated TPMS has proven to be able to be an alternative tool for the automotive sector to keep maintaining the tires and to improve a driving comfort and safety.