Catur Atmaji
Faculty of Mathematics and Natural Sciences, Gadjah Mada University, Bulaksumur, Yogyakarta, Indonesia 55281

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Analisis Hasil Proses Pemampatan JPEG dengan Metode Discrete Cosine Transform Utomo, Adi Prasetio; Putra, Agfianto Eko; Atmaji, Catur
IJEIS - Indonesian Journal of Electronics and Instrumentation Systems Vol 2, No 1 (2012): IJEIS
Publisher : Indonesian Computer, Electronics, and Instrumentation Support Society (IndoCEISS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB)

Abstract

AbstrakJPEG merupakan standar kompresi digital yang dikembangkan oleh Group Joints Photograpic Experts yang menggunakan kombinasi DCT dan pengkodean Huffman untuk mengkompresi suatu citra digital.[1]. Pemampatan JPEG merupakan algoritme pemampatan secara lossy. [2]. JPEG bekerja dengan mengubah gambar spasial dan merepresentasikan ke dalam pemetaan frekuensi. Salah satu metode dalam pemampatan JPEG yang dapat digunakan adalah metode DCT (Discrete Cosine Transform), dengan memisahkan antara informasi frekuensi yang rendah dan tinggi dari sebuah gambar.[3]            File yang digunakan adalah gambar grayscale dengan format bitmap, memiliki ukuran 26,422 bytes, resolusi 176x144 piksel.  Gambar diproses sesuai standar pemampatan JPEG, dianalisis hasil pemampatan berdasarkan variasi yang dilakukan pada tahapan block image transformation dan DCT quantization. Pengukuran kualitas gambar hasil pemampatan dilakukan secara subjektif melalui pandangan visual mata manusia dan secara objektif dengan parameter nilai PSNR dan rasio pemampatan            Dari penelitian dapat disimpulkan bahwa nilai PSNR dan rasio pemampatan gambar dapat digunakan sebagai parameter untuk mengukur kualitas gambar dan dapat diketahui penggunaan macroblock serta nilai step kuantisasi yang tepat untuk mendapatkan hasil optimal dalam pemampatan gambar grayscale. Kata kunci—JPEG,DCT,pemampatan JPEG, gamabr grauscale, PSNR, rasio pemampatan  Abstract JPEG is a digital compression standard developed by the Group of Experts Photograpic Joints using a combination of DCT and Huffman coding to compress a digital image.[1]. JPEG compression is a lossy compression algorithm. [2]. JPEG works by converting the spatial images and to represent frequency mapping.One of the methods in JPEG compression that can be used is a DCT method (Discrete Cosine Transform), with a separate low frequency information and high of an image. High frequency information will be selected to be eliminated which related to image compression and measurement quality of the image.[3]Files used are grayscale images with a bitmap format, has a size of 26.422 bytes, 176x144 pixel resolution. Image processed according to standard JPEG compression, the compression results are analyzed based on variations performed on block image  transformationandquantization. Measurement of quality of image compression is done subjectively through visual view of the human eye and objectively with the parameter value of PSNR and compression ratio.From the study it can be concluded that the value of PSNR and compression ratio of an image can be used as a parameter to measure the image quality and can be detected using macroblock  and value of quantization step which the right to obtain optimal results in compression of grayscale images Keywords—JPEG, DCT, JPEG compression, grayscale images, PSNR, compression ratio
Evaluation of Annual Allowable Cut (AAC) Determination of Teak Forest Plantations in Perum Perhutani, Indonesia Rohman, Rohman; Warsito, Sofyan P; Supriyatno, Nunuk; Purwanto, Ris Hadi; Atmaji, Catur
JURNAL MANAJEMEN HUTAN TROPIKA Vol 20, No 3 (2014)
Publisher : Bogor Agricultural University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (563.229 KB) | DOI: 10.7226/jmht.20.3.195

Abstract

The degradation of teak forest plantations in Java that are managed by Perum Perhutani (PP) continues to happen, and this is caused by some risk factors such as illegal logging, grazing, forest fire, and encroachment. However, these risk factors have not been considered by PP notably in annual allowable cut (AAC) determination of yield regulation. Therefore, the AAC value could be overestimated. The research was aimed at evaluating the method of AAC determination and proposing an alternative method that considers the risk factors. This research was conducted with a series of data analysis approach from the data on five planning periods. The research result showed that forest damage occurs in varied situations. On average, the rate of deforestation accounted for 0.8% per annum.The calculation of AAC by considering the rate of damage risk in normal condition approximately made up 70.8%. Thus, compared to another method without considering damage risk rate, overestimation constituted 29.2%. In brief, this had an impact on the decline of timber stock.Keywords: teak forest plantation, Perum Perhutani, casualty per cent, AAC
Evaluation of Annual Allowable Cut (AAC) Determination of Teak Forest Plantations in Perum Perhutani, Indonesia Rohman, Rohman; Warsito, Sofyan P; Supriyatno, Nunuk; Purwanto, Ris Hadi; Atmaji, Catur
Jurnal Manajemen Hutan Tropika Vol 20, No 3 (2014)
Publisher : Institut Pertanian Bogor (IPB University)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (563.229 KB) | DOI: 10.7226/jtfm.20.3.195

Abstract

The degradation of teak forest plantations in Java that are managed by Perum Perhutani (PP) continues to happen, and this is caused by some risk factors such as illegal logging, grazing, forest fire, and encroachment. However, these risk factors have not been considered by PP notably in annual allowable cut (AAC) determination of yield regulation. Therefore, the AAC value could be overestimated. The research was aimed at evaluating the method of AAC determination and proposing an alternative method that considers the risk factors. This research was conducted with a series of data analysis approach from the data on five planning periods. The research result showed that forest damage occurs in varied situations. On average, the rate of deforestation accounted for 0.8% per annum. The calculation of AAC by considering the rate of damage risk in normal condition approximately made up 70.8%. Thus, compared to another method without considering damage risk rate, overestimation constituted 29.2%. In brief, this had an impact on the decline of timber stock. 
Sistem Kendali Gimbal 2-Sumbu Sebagai Tempat Kamera Pada Quadrotor Menggunakan PID Fuzzy Haris, M Saiful; Dharmawan, Andi; Atmaji, Catur
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 7, No 2 (2017): October
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB) | DOI: 10.22146/ijeis.24220

Abstract

The function of camera gimbal control system that use in this research is to serves with the angle changes that occur due quadrotor maneuver. The PID control with tuning classical method has weakness, which is the PID variable not independently adjust to the environment, thus proposed using PID fuzzy control.Gimbal camera used in this study has a mechanical design with two joint (pitch and roll) and the BLDC motor as actuator. The angle changes that occur in the pitch and roll axis will be a feedback system. Then, fuzzy logic will tune the PID variable based on that feedback.Results of testing the system on 2-axis gimbal camera shows the PID fuzzy control generates better response in parameter risetime, overshoot, and settlingtime compared with PID control. Error input value range of [-30° 30°] and delta error of [-10° 10°] on the pitch and roll axes. The range of the output value for the pitch axis is, Kp at [40.2 46.2], Ki at [10.7 20.7], and Kd of [0.05 to 0.15]. The range of the output value for the roll axis is, Kp at [6.4 16.4], Ki at [17.3 to 27.3], and Kd at [0.08 0.16]. Speed response speed of pitch axis is 0.12 second and the roll axis is 1.07 seconds.
Analisis Perkiraan TDOA menggunakan Algoritma LMS Adaptif pada Pelacakan Paus Lodan Permana, Andriyan; Putra, Agfianto Eko; Atmaji, Catur
IJEIS - Indonesian Journal of Electronics and Instrumentation Systems Vol 5, No 1 (2015): IJEIS
Publisher : Indonesian Computer, Electronics, and Instrumentation Support Society (IndoCEISS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB)

Abstract

AbstrakPenelitian mengenai perkiraan TDOA dalam pelacakan paus lodan telah dilakukan[1] yang menggunakan Teager-Kaiser operator dalam peningkatan akurasi perkiraan nilai TDOA untuk pelacakan paus lodan menggunakan algoritma LMS adaptif. Namun demikian, belum dilakukan penelitian lebih lanjut mengenai faktor konvergensi (μ) yang tepat (cepat dan akurat) pada perkiraan TDOA menggunakan algoritma LMS adaptif untuk pelacakan paus lodan. Akan dilakukan analisis perkiraan nilai TDOA menggunakan algoritma LMS adaptif pada pelacakan posisi paus lodan dengan variasi nilai μ. Pada penelitian ini, sebagai acuan untuk menentukan nilai μ yang tepat, digunakan hasil pelacakan paus pada penelitian [2].Perkiraan TDOA menggunakan algoritma LMS Adaptif pertama kali dipublikasikan oleh Benesty [3]. Pendekatan yang dilakukan berdasarkan pada perkiraan tanggap impulsional dari sumber ke penerima. Pada algoritma LMS adaptif dilakukan pembaruan nilai koefisien dengan μ sebagai langkah adaptasi. Nilai TDOA diperoleh dari selisih jarak dua tanggap impulsional.Dari hasil penelitian diperoleh hasil bahwa perubahan nilai μ mempengaruhi kecepatan perkiraan TDOA menggunakan algoritma LMS adaptif. Akan tetapi, nilai μ yang tidak tepat mengakibatkan hasil pelacakan paus tidak akurat. Dari penelitian ini diperoleh nilai μ terbaik untuk perkiraan TDOA menggunakan algoritma LMS adaptif pada pelacakan posisi paus lodan adalah 0.01. Kata kunci— perkiraan TDOA, LMS adaptif, faktor konvergensi, pelacakan paus lodan AbstractResearch on TDOA estimation in sperm whale tracking has been done [1] that uses the Teager - Kaiser operator in improving accuracy the TDOA estimation using adaptive LMS algorithm on sperm whale tracking. However, further researches on the right convergence factor (μ) (fast and accurate) in TDOA estimation using adaptive LMS algorithms for sperm whale tracking have not been performed. Will be analyzed the TDOA estimation using adaptive LMS algorithm in sperm whale tracking with the variation of μ. As a reference to determine the right value of μ, the results of sperm whale tracking[2] is used.TDOA estimation using Adaptive LMS algorithm was first published by Benesty [3]. The approach taken is based on estimation of the impulse responses from source to receivers. In the adaptive LMS algorithm function updates the coefficient with μ as adaptation step. TDOA values obtained from the difference between the two impulse responses.From the results, values changing of μ affect the speed of TDOA estimation using the LMS adaptive algorithm. However, the wrong value of μ is lead to inaccurate sperm whale tracking results. The best value of μ for TDOA estimation using the LMS adaptive algorithm for sperm whale tracking is 0.01. Keywords— TDOA estimation, adaptive LMS, convergence factor, sperm whale tracking
Implementasi Kendali Logika Fuzzypada Robot Line Follower Putu Pratama, Gilang Nugraha; Dharmawan, Andi; Atmaji, Catur
IJEIS - Indonesian Journal of Electronics and Instrumentation Systems Vol 4, No 1 (2014): IJEIS
Publisher : Indonesian Computer, Electronics, and Instrumentation Support Society (IndoCEISS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB)

Abstract

Robot line follower merupakan robot otonom yang dapat mengikuti jalur. Jalurnya bisa berupa garis berwarna hitam diatas permukaan putih atau sebaliknya. Pada penelitian ini, robot line follower menggunakan sistem kendali logika fuzzy dengan metode Mamdani. Selama ini robot line follower kebanyakan dirancang untuk jalur dengan lebar yang tetap, namun dengan sistem kendali logika fuzzy ini dapat mengenali jalur dengan variasi lebar antara satu hingga delapan titik sensor. Robot line follower ini mengimplementasikan 18 aturan fuzzy untuk memetakan antara antecedent posisi dan lebar jalur, dengan consequent kecepatan laju robot. Aturan fuzzy terdiri dari masing-masing 9 aturan untuk kondisi jalur tunggal dan jalur percabangan dua jalur. Robot line follower ini mampu menganalisis 57 case jalur dengan kendali fuzzy, mulai dari lebar jalur 2 hingga 12 cm. Dimana 36 case analisis jalur tunggal dan 21 casejalur percabangan dua jalur. Robot line follower ini juga mampu menyesuaikan kecepatan laju sesuai lebar jalurnya. Kata kunci— kendali logika fuzzy, kendali Mamdani, robot line follower Line follower Robot is an autonomous robot that can follow a track. The track can be a black line on a white surface or vice versa. In this study, the line follower robot using fuzzy logic control system by the method of Mamdani. Mostly line follower robots are designed with a fixed width, but with fuzzy logic control system itcan recognize the wide variation between one to eight pointsof sensor. This line follower robot implements18 fuzzy rules to map between the antecedents position and width of the line, with a consequents speed rate of the robot. There are 9 rules each  for single line and two routes branching paths. This line follower robot is designedwith capabilityto analyze 57 cases, the width of the line from 2 to 12 cm. There are 36 casesof analysis on a single line and 21 cases on two lines branching paths. This line follower robot can adjust it’s speed depend on the wide of the track. Keywords— fuzzy logic controller, Mamdani-controller, line follower robot
Analisis Perbedaan Pola Sinyal EEG Berdasarkan Jenis Kelamin Yang Berbeda Saat Numerical Stroop Task Dimas, Riswandha Latu; Atmaji, Catur
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 8, No 1 (2018): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB) | DOI: 10.22146/ijeis.34383

Abstract

Cognitive process show how brain work from stimulus reception until stimuls reaction. With electroencephalogram (EEG) device, cognate process can be observerd in brain signal or EEG signal form. In cognitive process different kind of stimulus could affect generated brain signal. Also, given interference in cognitive prcess could affect brain signal. In this research, conducted observation whether gender difference has effect in cognitive process. Numerical stroop task with three kinds of conditions (congruence, incongruence, and neutral) are used as reference in signal observation process which is generated when the cognitive process in difference genders are done. The resulting EEG signal then conducted three kinds of analysis that is ERP analysis, reaction time, and energy analysis. The result of ERP analysis show both subject class have difference in response time that indicated with P3 peak time. On average, respons time in female (kongruent = 623,34 ms; inkongruent = 645,18 ms ; neutral = 614,91 ms)subject class is faster than male (kongruent = 709,67 ms; inkongruent = 745,00 ms; neutral =715,37 ms) subject class. Energy analysis show when numerical stroop task takes place, left side of the brain (51,36%) and cetral side of the brain (50,65%) more dominant than others parts of the brain.
Rancang Bangun Purwarupa Penerima Paket APRS Berbasis Raspberry Pi 2 untuk Stasiun Bumi Putra, Agfianto Eko; Nugroho, Unggul Adhi; Ardi Sumbada, Bakhtiar Alldino; Atmaji, Catur
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 9, No 1 (2019): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB) | DOI: 10.22146/ijeis.44299

Abstract

The design of Raspberry Pi 2-based APRS packets for UGM earth stations has been designed, which is much cheaper than commercial devices on the market. A TV tuner is used as a signal receiver, the receiver is accessed via a laptop wirelessly. A directed antenna with a controller is used to automatically point to the satellite. The test was carried out by receiving the APRS package emitted by the International Space Station (ISS) satellite and the LAPAN-A2 satellite. The results showed that the tool was able to get the ISS satellite APRS package with a total of 6 packages out of 10 packets emitted. The package received has an average amplitude of 1,200 Hz and 2,200 Hz which is much smaller than the overall audio amplitude. This indicates that there is high noise in the signal. While the APRS package from the LAPAN-A2 satellite has not been successfully obtained.
Implementasi Kendali Logika Fuzzypada Robot Line Follower Putu Pratama, Gilang Nugraha; Dharmawan, Andi; Atmaji, Catur
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 4, No 1 (2014): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB) | DOI: 10.22146/ijeis.4221

Abstract

Robot line follower merupakan robot otonom yang dapat mengikuti jalur. Jalurnya bisa berupa garis berwarna hitam diatas permukaan putih atau sebaliknya. Pada penelitian ini, robot line follower menggunakan sistem kendali logika fuzzy dengan metode Mamdani. Selama ini robot line follower kebanyakan dirancang untuk jalur dengan lebar yang tetap, namun dengan sistem kendali logika fuzzy ini dapat mengenali jalur dengan variasi lebar antara satu hingga delapan titik sensor. Robot line follower ini mengimplementasikan 18 aturan fuzzy untuk memetakan antara antecedent posisi dan lebar jalur, dengan consequent kecepatan laju robot. Aturan fuzzy terdiri dari masing-masing 9 aturan untuk kondisi jalur tunggal dan jalur percabangan dua jalur. Robot line follower ini mampu menganalisis 57 case jalur dengan kendali fuzzy, mulai dari lebar jalur 2 hingga 12 cm. Dimana 36 case analisis jalur tunggal dan 21 casejalur percabangan dua jalur. Robot line follower ini juga mampu menyesuaikan kecepatan laju sesuai lebar jalurnya. Kata kunci? kendali logika fuzzy, kendali Mamdani, robot line follower Line follower Robot is an autonomous robot that can follow a track. The track can be a black line on a white surface or vice versa. In this study, the line follower robot using fuzzy logic control system by the method of Mamdani. Mostly line follower robots are designed with a fixed width, but with fuzzy logic control system itcan recognize the wide variation between one to eight pointsof sensor. This line follower robot implements18 fuzzy rules to map between the antecedents position and width of the line, with a consequents speed rate of the robot. There are 9 rules each  for single line and two routes branching paths. This line follower robot is designedwith capabilityto analyze 57 cases, the width of the line from 2 to 12 cm. There are 36 casesof analysis on a single line and 21 cases on two lines branching paths. This line follower robot can adjust it?s speed depend on the wide of the track. Keywords? fuzzy logic controller, Mamdani-controller, line follower robot
Peningkatan Skalabilitas Mini Weather Station Portable berbasis Internet of Things Putro, Nur Achmad Sulistyo; Atmaji, Catur; Devianto, Kristiawan; Perwira, Zandy Yudha
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 9, No 2 (2019): October
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijeis.50377

Abstract

Indonesia is a country that has unique weather that provides not only abundant natural resources but also can causes disasters at any time. To reduce the threat of losses, observing weather elements using a weather station is a solution that can be used. The development of systems related to environmental monitoring and weather stations is not new. However, most research focuses on various innovations in utilization, low cost and power savings. These studies have not touched on the aspect of ease of system development, especially in the concept of adding nodes. Indonesia, as a country with diverse regional topography, needs an integrated weather monitoring system with the concept of centralized data collection to get a complete picture.In this study, a portable mini weather station system was built named Amicagama. This system is built with the concept of high scalability which means the system is designed to be used publicly, with each user able to manage the nodes which are their respective weather stations. Management by each user here means that each user can manage weather data to be submitted, add nodes at a new location, and can delete nodes at a certain location if something unexpected happens.