The application of control systems in precision irrigation is critical to ensure the accurate distribution of water in crops under various uncertainties. Shifts in the loading of the water supply on the control valve can be a significant uncertainty. Changes in weather and the uncertainty of the water level in the reservoir are also challenging issues. Sliding Mode Control (SMC) is a robust control technique that is simple to apply to deal with uncertainty, while Fast Terminal Sliding Mode Control (FTSMC) has the benefit of the rapid convergence. The DC electric motor, which is a common component of electric control valves, can be employed in designing control techniques for precision irrigation applications. This study aims to design a proposed experimental-based method, namely FTSMC for valve regulation under water load uncertainty for precision irrigation application. Modification of the signum function should be used to eliminate the chattering effect in real experiments.The results of experiments showed that the proposed method was superior to the conventional Proportional Integral Derivative (PID) and traditional SMC techniques in terms of overshoot, convergence rate and error. Because of those reasons, the FTSMC approach should be implemented on control valves against load uncertainty in precision irrigation applications.
This research described the use of total communication learning model in enhancing the language capacity of deaf children. Conventionally, the learning model employed in teaching deaf children is based on sign language and this limit their ability to communicate with people that are not deaf. Furthermore, these children are marginalized from the society because of their inability to understand the language used for public communication and, consequently, there is a problem of communication between them and other people in the society. The research was conducted through the use of qualitative research method while data as collected through the use of observation, in-depth interview, and focus group discussion. The data collected was verified through the use of source triangulation and descriptive analysis. The research revealed that total communication learning model through the use of pictures, writings, and readings increases and enhances the language skill of deaf children. It was also discovered that the model helped these children to communicate verbally with other people in their community. Conclusively, the research showed that it is possible for deaf children to communicate with other people without relying on sign language only.
This article discusses the empowerment of coastal communities and the role of local informal leader in mangrove forest conservation. Mangrove forest has an ecological function of protecting the environment, including: resisting coastal abrasion, tsunamis, and breeding grounds for marine biota. Socio-economically, mangrove forest provides the beauty and comfort of the environment and is as learning facilities, so that they can be packaged as a destination for tourism. The condition of mangrove forest has been damaged but there have not been many results of conservation efforts that have been made. The conservation program is top-down and does not involve local community participation. In order to realize community participation in mangrove forest conservation an active and creative role is needed from informal leaders. This study uses a qualitative approach and is carried out in two districts, namely Jember and Banyuwangi Regencies. The result shows that local informal leaders have a strategic position, unique, respected, able to be role models and drivers of community activities so that coastal communities can jointly carry out mangrove forest conservation activities. Keywords: local informal leaders, community empowerment, participation, conservation, mangrove forests.
This paper presents a simple and straightforward design of a discrete-time fractional-order odd-harmonics repetitive controller (RC). Unlike general RC designs, the proposed method utilizes an internal model with a half-period delay and a stabilizing controller with a fractional phase lead compensator. First, the odd-harmonics internal model representing odd-harmonics frequencies is constructed by using the information of the reference’s basis period and the preferred tracking bandwidth. Secondly, an optimization problem synthesized from the stability condition of the RC closed-loop system is solved to obtain the fractional phase lead compensator. Finally, the fractional term of the stabilizing controller is realized by using a causal and stable infinite impulse response (IIR) filter, where the filter coefficients are computed by applying the Thiran formula. Simulation and experimental validation on a servomotor system are conducted to verify the effectiveness of the proposed design.
The frequency measurement has very important role in the field of signal measurement system mainly for acquisition data of pulse signal on the turbine flow meter. To meet the accurate measurement and become independent technology, a local product of calibrated frequency meter is needed. The purpose of this research is to create a prototype of calibrated frequency meter until range of 2000 Hz to guarantee the truth measurement internationally. Microcontroller of Arduino Uno board with 16-bit counter ability is used to calculate the frequency. The measurement result is displayed in real time by serial communication and on the Liquid Crystal Display. That prototype of frequency meter has been calibrated using standard of DS340 that is traceable to SI units through primary standard of frequency using cesium at Research Center for Metrology LIPI. The results of calibration and measurement on the measuring range of (10 ~ 2000) Hz obtained that the prototype of frequency meter has the maximum possible error of 0.7 Hz. The measurement traceability of prototype of frequency meter with the resolution of 0.1 Hz and the relative accuracy of 0.03% full scale has been successfully built .Keywords: Frequency meter, microcontroller, calibration, traceability, cesium standard AbstrakPengukuran besaran frekuensi sangat penting peranannya dalam bidang sistem pengukuran sinyal terutama untuk akuisisi data sinyal pulsa pada pengukur aliran jenis turbin. Untuk memenuhi kebutuhan pengukuran yang akurat dan menjadi mandiri secara teknologi diperlukan produk frekuensi meter lokal yang terkalibrasi. Tujuan penelitian ini adalah membuat prototipe frekuensi meter sampai rentang ukur 2000 Hz yang terkalibrasi sehingga terjamin nilai kebenaran pengukurannya secara internasional. Digunakan mikrokontroler board Arduino Uno dengan kemampuan pencacah 16 bit untuk menghitung frekuensi. Hasil pengukuran ditampilkan secara real time komunikasi serial serta pada Liquid Crystal Display (LCD). Telah dilakukan kalibrasi prototipe frekuensi meter tersebut menggunakan standar DS340 yang telah tertelusur ke satuan SI melalui standar primer frekuensi cesium Puslit Metrologi LIPI. Dari hasil kalibrasi dan pengukuran pada rentang ukur (10 ~2000) Hz didapat bahwa prototipe frekuensi meter ini memiliki kemungkinan error terbesar sebanyak 0,7 Hz. Telah berhasil dibangun ketertelusuran pengukuran prototipe frekuensi meter tersebut dengan resolusi 0,1 Hz dan akurasi 0,03% relatif skala penuh.Kata kunci: Frekuensi meter, mikrokontroler, kalibrasi, ketertelusuran, standar cesium. _______________________________________________________________________________________ PendahuluanPengukuran besaran frekuensi sangat penting peranannya dalam aplikasi pengukuran sinyal. Berbagai teknologi dan aplikasi bergantung pada ketepatan pengukuran waktu dan frekuensi termasuk pasar keuangan, jaringan telepon kabel dan nirkabel, stasiun radio broadband, jaringan listrik, navigasi sistem radio, dan aplikasi-GPS [1] _______________
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