Judul: Pengembangan Prototipe Sistem IoT Monitoring Hidroponik NFT Berbasis ESP8266
Abstrak: Budidaya hidroponik dapat dilakukan pada lahan terbatas, cuaca ekstrim, dan persedian air terbatas. Namun agar budidaya hidroponik berhasil, perlu diperhatikan aspek kualitas larutan nutrisi berupa nilai TDS, pH, debit aliran, suhu lingkungan, dan lain-lain. Penelitian ini bertujuan untuk mengembangkan sistem IoT pemantau hidroponik nutrient film technique (NFT) dengan sensor pH, TDS, suhu, aliran dan ketinggian larutan nutrisi; serta suhu lingkungan, kelembapan, dan intensitas cahaya. Sistem ini menggunakan mikrokontroler Wemos D1 mini ESP8266 dengan tambahan modul ADS1115. Penelitian dilakukan dalam lima tahap yaitu analisis kebutuhan, desain prototipe, interfacing sensor, integrasi, dan pengujian lapang. Penelitian ini berhasil mengembangkan prototipe sistem IoT pemantau hidroponik NFT berbasis ESP8266 dengan tujuh jenis sensor yang telah disebutkan di atas. Data pemantauan dikirim ke platform IoT ThingSpeak secara real time.
Keyword: ESP8266, hydroponics, IoT, monitoring, NFT

Judul: Development of Microclimate Monitoring System for Multi-Greenhouse using Internet of Things
Abstrak: Suhu udara, kelembapan udara, dan intensitas cahaya merupakan parameter lingkungan mikro di dalam rumah tanaman yang berpengaruh terhadap pertumbuhan tanaman dan perlu dilakukan pemantauan. Saat ini, Internet of Things (IoT) merupakan teknologi yang mumpuni dan dapat digunakan untuk melakukan pemantauan lingkungan mikro rumah tanaman di berbagai lokasi secara langsung. Tujuan penelitian ini yaitu rancang bangun sistem pemantauan suhu nutrisi, suhu udara, kelembapan udara, dan intensitas cahaya pada berbagai rumah tanaman berbasis IoT. Penelitian ini menggunakan metode System Development Life Cycle (SDLC) yang terdiri dari: (1) analisis kebutuhan sistem, (2) desain sistem, (3) implementasi sistem, dan (4) pengujian sistem. Perangkat elektronika yang digunakan yaitu sensor DHT21, BH1750, DS18B20, dan mikrokontroler ESP32. Hasil perhitungan Root Mean Square Error (RMSE) dan Mean Absolute Percentage Error (MAPE) pada kalibrasi sensor yang rendah menunjukkan nilai eror data dari pembacaan sensor yang kecil. Desain sistem dibuat menggunakan rancangan database dan entity relationship diagram. Sistem diimplementasikan pada berbagai rumah tanaman yaitu dua greenhouse tipe standard peak dan satu plant factory. Berdasarkan hasil uji System Usability Scale (SUS), didapatkan nilai SUS 75,67 yang artinya sistem dapat diterima oleh pengguna dan termasuk kategori sistem yang baik pada kelas B. Kesimpulan dari penelitian ini yaitu sistem pemantauan lingkungan mikro pada berbagai rumah tanaman berhasil dilakukan menggunakan perangkat elektronika berbasis IoT yang dapat diakses oleh pengguna pada web server., Air temperature, air humidity, and light intensity are microclimate parameters in greenhouse that affect plant growth and must be monitored. Currently, the Internet of Things (IoT) is powerful and can be used to monitor microclimate parameters in multi-greenhouse at various locations directly. The purpose of this research is to design and develop a system for monitoring nutrient temperature, air temperature, air humidity, and light intensity in multi-greenhouse based on IoT. This research used the System Development Life Cycle (SDLC) method, which consists of: (1) system requirement analysis, (2) system design, (3) system implementation, and (4) system testing. The electronic devices used were DHT21, BH1750, DS18B20 sensors, and ESP32 microcontroller. The low values of Root Mean Square Error (RMSE) dan Mean Absolute Percentage Error (MAPE) obtained in sensor calibration indicate small data errors from sensors. The system design was made with a database design and entity relationship diagram. The system was successfully implemented in multi-greenhouse which two greenhouse standard peak type and a plant factory. Based on the results of System Usability Scale (SUS) test, the system received SUS score of 75.67, which means that system was acceptable to users and included good category in class B. The conclusion of this research was microclimate monitoring system in multi-greenhouse has been successfully implemented using electronic devices based on IoT that can be accessed by users on a web server.
Keyword: ESP32, Internet of Things, rumah tanaman, sensor lingkungan, sistem informasi

Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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