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Kombinasi Steganografi Berbasis Bit Matching dan Kriptografi DES untuk Pengamanan Data Prasetiyo, Budi; Gernowo, Rahmat; Noranita, Beta
Scientific Journal of Informatics Vol 1, No 1 (2014): May 2014
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sji.v1i1.3643

Abstract

Pada penelitian ini dilakukan kombinasi steganografi dan kriptografi untuk pengamanan data dengan tidak mengubah kualitas media cover. Metode steganografi yang digunakan dengan melakukan pencocokan bit pesan pada bit MSB citra. Proses pencocokan dilakukan secara divide and conquer. Hasil indeks posisi bit kemudian dienkripsi menggunakan algoritma kriptografi Data Encryption Standard (DES). Masukkan data berupa pesan teks, citra, dan kunci. Output yang dihasilkan berupa chiperteks posisi bit yang dapat digunakan untuk merahasiakan data. Untuk mengetahui isi pesan semula diperlukan kunci dan citra yang sama. Kombinasi yang dihasilkan dapat digunakan untuk pengamanan data. Kelebihan metode tersebut citra tidak mengalami perubahan kualitas dan kapasitas pesan yang disimpan dapat lebih besar dari citra. Hasil pengujian menunjukkan citra hitam putih maupun color dapat digunakan sebagai cover, kecuali citra 100% hitam dan 100% putih. Proses pencocokan pada warna citra yang bervariasi lebih cepat. Kerusakan pesan dengan penambahan noise salt and peper mulai terjadi pada nilai MSE 0,0067 dan gaussian mulai terjadi pada nilai MSE 0,00234. 
Kombinasi Steganografi Berbasis Bit Matching dan Kriptografi DES untuk Pengamanan Data Prasetiyo, Budi; Gernowo, Rahmat; Noranita, Beta
Scientific Journal of Informatics Vol 1, No 1 (2014): May 2014
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sji.v1i1.3643

Abstract

Pada penelitian ini dilakukan kombinasi steganografi dan kriptografi untuk pengamanan data dengan tidak mengubah kualitas media cover. Metode steganografi yang digunakan dengan melakukan pencocokan bit pesan pada bit MSB citra. Proses pencocokan dilakukan secara divide and conquer. Hasil indeks posisi bit kemudian dienkripsi menggunakan algoritma kriptografi Data Encryption Standard (DES). Masukkan data berupa pesan teks, citra, dan kunci. Output yang dihasilkan berupa chiperteks posisi bit yang dapat digunakan untuk merahasiakan data. Untuk mengetahui isi pesan semula diperlukan kunci dan citra yang sama. Kombinasi yang dihasilkan dapat digunakan untuk pengamanan data. Kelebihan metode tersebut citra tidak mengalami perubahan kualitas dan kapasitas pesan yang disimpan dapat lebih besar dari citra. Hasil pengujian menunjukkan citra hitam putih maupun color dapat digunakan sebagai cover, kecuali citra 100% hitam dan 100% putih. Proses pencocokan pada warna citra yang bervariasi lebih cepat. Kerusakan pesan dengan penambahan noise salt and peper mulai terjadi pada nilai MSE 0,0067 dan gaussian mulai terjadi pada nilai MSE 0,00234.
STUDI AWAL DAMPAK PERUBAHAN IKLIM BERBASIS ANALISIS VARIABILITAS CO2 DAN CURAH HUJAN (Studi Kasus; Semarang Jawa Tengah) Gernowo, Rahmat; Adi, Kusworo; Arifin, Zaenal
BERKALA FISIKA Vol 15, No 4 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Impacts of climate change marked by the increasing emissions of CO2 in the air and increased precipitation make various parties began to feel the need to measure the gas content on a regular basis.These gases gradually accumulating in Earth's atmospheric layers. However, the desire was constrainedby a number of issues which then affect the accuracy of the continuous mapping circulating gas in theatmosphere. Researchers speculate that the amount of CO2 and other gases is growing each day due tothe many additional human-produced carbon emissions from burning fossil fuels. The results obtained bythe pattern of variability in Semarang rising CO2 and rising precipitation trends show an indication ofclimate change has occurred. It was proven occurrence of climate anomalies and the previous year.Keywords: CO2 variability, Rainfall Semarang
Monsoon Effect at Flood Phenomena on 2002 and 2007 in DKI-JAKARTA Gernowo, Rahmat
BERKALA FISIKA Vol 12, No 1 (2009): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The monsoon effect one think especially represent to important matter as causes of floods happen in area of Jakarta. The research of convection pattern above area of DKI-Jakarta based on to existing perception data, which is expected will give the understanding of growth of convection cloud yield torrential rains and deliver floods in DKI-Jakarta on 2002 and 2007. The result of research into whereas in this research is obtained by the rain study of extreme in DKI-Jakarta. As rainfall data result of average from some stations is residing in DKI-Jakarta. The result of research is obtained by comparison analysis whereas, that cloud dynamics in DKI-Jakarta happened at around of December, January and February, where periodicity of monsoon takes place. Keywords: Monsoon, flood and cloud dynamics.
MODEL ARIMA UNTUK PREDIKSI CURAH HUJAN STUDI KASUS SEMARANG JATENG A Rofik, Muchammad; Gernowo, Rahmat; Setyawan, Agus; Nursamsiah, Nursamsiah
BERKALA FISIKA Vol 15, No 3 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Modeling and prediction of rainfall in 2010 in Central Java BMKG Climatological Station has been done with ARIMA approach. The goal is to determine the historical pattern of the dataand then extrapolates this pattern into the future based on the assumption of continuity. Rainfalldata of 2000-2009 is a time series that can be predicted into the future using ARIMA. In thisstudy using two approaches for prediction of rainfall in 2010. The results were correlated with aprediction of rainfall data observed in 2010. Obtained a correlation of 71.1% and 75.48%.Keywords: ARIMA, rainfall, predictions, models
Model Perhitungan Titik Gelombang Pecah (Point Breaker Wave) Disekitar Pantai Gernowo, Rahmat
BERKALA FISIKA Vol 12, No 2 (2009): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

In this paper will be studied numerically the point breaker wave characteristic on shore. The model equation of the surface wave based on the equations which is governed by combining the refraction-diffraction on mild slope bottom. As mathematical analysis approximation, the finite difference methods was us for understanding the characteristic behavior of the surface wave on shore. The numerical simulation is obtained from the result of the numerical computation. There are significance changes of the height of wave, which is influenced by mild slope bottom factor (shoaling), diffraction and refraction.           Key Word: Point Breaker Wave, finite difference, diffraction and reffraction.
METODE AUTOREGRESSIVE INTEGRATED MOVINGAVERAGE (ARIMA) DAN METODE ADAPTIVE NEURO FUZZY INFERENCE SYSTEM (ANFIS) DALAM ANALISIS CURAH HUJAN Wulandari, Rosita Ayu; Gernowo, Rahmat
BERKALA FISIKA Vol 22, No 1 (2019): Berkala Fisika Vol. 22 No. 1 Tahun 2019
Publisher : BERKALA FISIKA

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Abstract

Information of rainfall prediction is important for Indonesian peoples. Many statistical methods can be used in rainfall prediction, they are ARIMA (Autoregressive Integrated Moving Average) and ANFIS (Adaptive Neuro Fuzzy Inference System) methods. The purpose of this study was to compare between ANFIS method and ARIMA method to get rainfall prediction in some periods. The ARIMA method was time series data analysis often used in forecasting. While the ANFIS method was forecasting method based on rarely found time series events that are pure linear or non-linear. Based on this study, the ANFIS method has a good accuracy for time series data analysis compared with the ARIMA method. The ANFIS method has 6.9811 for the result of correlation and 87.29% for the RMSE, while result of correlation for the ARIMA method is 14.037 with 24.92% for RMSE. The ARIMA method is not good for prediction of daily data cases and non-linear data, so that the result is not actual which has a constant and flat for data prediction. Keywords: ARIMA, ANFIS, time series data, linear, non-linear 
SISTEM PENGENALAN WAJAH DENGAN METODE EIGENFACE DAN JARINGAN SYARAF TIRUAN (JST) Mulyono, Tri; Adi, Kusworo; Gernowo, Rahmat
BERKALA FISIKA Vol 15, No 1 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The development of security systems led to the development of face recognition system using image processing techniques.Research was conducted to identify a face image automatically with theeigenface method. The method used is a normalization, eigenface, neural network training and testing.Eigenface is used to reduce the dimension vector face becomes much simpler (eigen vector). Eigen vectorsobtained are used by back propagation neural network training process and recognition. Then do thetesting process using the image of a face that has not been used in the training process.The results showed the use of neural networks and eigenface to face recognition can give a goodaccuracy. The system is able to produce an acuracy of 84.6% with a FAR (False Acceptance Rate) =16.2%, FRR (False Rejection Rate) = 20% and EER (Equal Error Rate) = 0.3.Keywords : face recognition, eigenface, eigen vector, neural network
IDENTIFIKASI FOKUS MIKROSKOP DIGITAL MENGGUNAKAN METODE OTSU Putranto, Ari Bawono; Adi, Kusworo; Gernowo, Rahmat
BERKALA FISIKA 2014: Berkala Fisika Vol. 17 No. 4 Tahun 2014
Publisher : BERKALA FISIKA

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Abstract

A study to identify focus on a digital microscope has been done using a threshold value of the object microscope image obtained by Otsu method. Microscope image of the object captured by the change from a maximum to a minimum distance between the object and the microscope objective lens to record the amount of movement of a motor stepper and calculates the Otsu threshold value on each image. Based on data from a Otsu threshold value of each microscope image of the object to the changes within the object can be inferred the existence of a relationship between the position of an object to focus the microscope with the image of the threshold value that is increasingly the focus of an image , the image of the Otsu threshold values ​​obtained are also getting smaller. In this study done by testing two samples as objects of microscope that single hair samples and samples collection of several hairs were each placed on a microscope glass slide. Data collection and observation results show that for a single hair samples obtained object focus Otsu threshold value T = 97 and sample an object consisting of a collection of some of the hair is obtained Otsu threshold value T = 127. But the testing of two samples showed differences influenced by the ratio between the number of pixels on the image and the background image of an object caused by the influence of the intensity of the light source of the microscope. Keywords: Focus Identification, Digital Microscope, Otsu Threshold
PEMBUATAN SISTEM KENDALI POSISI AUTOFOKUS EKSPERIMEN LENSA DENGAN MOTOR LANGKAH Gunadi, Isnain; Gernowo, Rahmat; Adi, Kusworo
BERKALA FISIKA 2015: Berkala Fisika Vol. 18 No. 4 Tahun 2015
Publisher : BERKALA FISIKA

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Abstract

The automatic lens experiment with stepper motor position control has been made. Main component of this device are stepper motor which move the lens and screen. Microcontroller is contens the programs of motor movement controller. The screen contain of Light Dependent Resistor (LDR) as voltage sensor. This image will focused when the voltage in the screen is maximum. The result of test show that the automatic measurement is more accurate than manual measurement.Keywords: Auto-Fokus, LDR, IPMC, LSW, EAPs, VCM