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INDONESIA
GEMA TEKNOLOGI
Published by Universitas Diponegoro
ISSN : 08520232     EISSN : 2656582X     DOI : -
Core Subject : Science,
Computer Science & IT
Gema Teknologi Journal (pISSN : 0852-0232, eISSN : 2656-582X) is an open access journal published by Vocational School, Diponegoro University, Indonesia. Gema Teknologi publishes articles from various engineering disciplines (the results of original scientific research or new scientific studies of literature). Editor receives articles both in English and Indonesian. Gema Teknologi Journal is published 2 (two) times a year, on April and October.
Arjuna Subject : -
Articles 217 Documents
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SISTEM INVENTARISASI PENGGUNAAN PERALATAN DAN BAHAN PADA MEJA PRAKTIKUM PLC DI POLITEKNIK MANUFAKTUR NEGERI BANGKA BELITUNG MENGGUNAKAN BARCODE SCANNER Nofriyani Nofriyani; Adhi Budiono; Charlotha Charlotha; Indra Dwisaputra; Dedy Ramdhani
Gema Teknologi Vol 21, No 2 (2021): October 2020 - April 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i2.31659

Abstract

In the Programmable Logic Controller (PLC) course at Polmanbabel, students use a practicum table containing practicum equipment such as computer units, compressors, PLC units, pneumatic valves, sensors, jumper cables, etc. Before and after practicum, students are required to do an inventory of equipment and materials contained on this practicum desk. The inventory process is still done manually, where students write the name of the equipment, check the presence of the equipment, and calculate the amount. The thing that was complained by lecturers was the confiscation of practicum time as a result of the manual inventory process. Based on this, a new inventory system was created that uses the application and is equipped with a barcode scanner that is able to minimize the time and possibility of misplacement of the device. Based on the results of experiments, it can be seen that this system is able to minimize inventory time by an average of 14.65 minutes compared to manual inventory systems.
ANALISA KINERJA CNG COOLER PADA SISTEM CNG PLANT Seno - Darmanto; Muhammad Fahrudin
Gema Teknologi Vol 21, No 2 (2021): October 2020 - April 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i2.17963

Abstract

CNG Cooler is a heat exchanger in CNG Plant System which has function to reduce CNG temperature. CNG (Compressed Natural Gas) is natural gas which compressed by gas compressor from normal pressure up to certain high pressure. CNG Plant is gas storage and supply facility for PLTGU when it work at peak load hours. CNG Cooler reduce temperature of CNG which out from gas compressor before saved in storage utility which purpose to avoid over heating in the next process, increase durability of the next process utility, and make gas storage utility design easy.
PENGARUH RASIO BAHAN BAKU TEPUNG KOMPOSIT (UBI KAYU, JAGUNG DAN KEDELAI HITAM) PADA KUALITAS PEMBUATAN BERAS ANALOG Isti Pudjihastuti; Edy Supriyo; Hafiz Rama Devara
Gema Teknologi Vol 21, No 2 (2021): October 2020 - April 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i2.32923

Abstract

The increase population affects an increase in total of consumption of Indonesian people towards rice, which encourages Indonesia to import rice. One of the alternatives that can be done is by using potential non-rice raw materials such as tubers. In this study, the raw materials for composite flour from cassava (Manihot esculenta), corn (Zea mays) and black soybeans (Glycine Sojo) were used, which are the basic ingredient for analog rice. The purpose of this study was to examine the effect of raw material composition on nutritional value (carbohydrate, protein, fat, water and ash content) analog rice compared to ordinary rice, examine the physico-chemistry (kamba density, water absorption and cooking time) of analog rice compare to paddy rice and also to define raw material composition and best temperature, organoleptic test covering color, aroma, texture and taste. The process of making analog rice consists of several stages of research, such as the stage of making composite flour, cooking the composite flour dough, making analog rice, drying analog rice and analyzing the results. The variables used were the ratio of flour composition and the effect of extrusion temperature. Based on proximate analysis on various compositions, obtained sample 5 (60% cassava flour, 15% corn flour and 25% black soybean flour) as analog rice with the best formulation. Based on the proximate analysis of the effect of temperature, the temperature was 75 °C as the optimum temperature for the extraction process. The results of the physical analysis of the best analog rice in this study showed that analog rice from a composite of cassava flour, corn flour and black soybean flour had a kamba density of 0.46 g / mL, a water absorption capacity of 60.52% and a cooking time of 46 minutes. In this sample, analog rice has a texture, aroma and appearance similar to rice in general, although analog rice from composite flour tends to have a savory taste arising from black soybeans.
SURVEI METODE PENGUKURAN APLIKASI CHATBOT BERBASIS MEDIA SOSIAL Ratna Ayu Sekarwati; Ahmad Sururi; Rakhmat Rakhmat; Miftahul Arifin; Arief Wibowo
Gema Teknologi Vol 21, No 2 (2021): October 2020 - April 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i2.36170

Abstract

The design of Chatbot aims to facilitate social activities in all areas to be considered. Chatbot is one type of machine that can communicate with humans using natural language. Communication happening via chat is a written conversation. Chatbot is a form of application implementation from Natural Language Processing (NLP) that belongs to one branch of artificial intelligence or Artificial Intelligent (AI). Social Media now provides a service that allows developers to process and integrate chatbot applications. This paper aims to review the papers that build chatbot applications in various social media using various testing methods. The contribution of this paper is to determine which method is able to measure the level of chatbot accuracy well. This review paper will choose the equation of the most widely used test methods and social media from various papers so that further research is expected to implement the right testing methods and use better social media in terms of user experience, features, and services. The review paper shows that the Black-box and System Usability Scale testing methods are most used in the review paper. This testing method is a type of method that performs testing of the flow and how the chatbot works to achieve functional validation throughly.
PEMANFAATAN METODE WAVS (WEB APPLICATION SECURITY SCANNERS) MENGGUNAKAN BURP SUITE TOOLS DALAM AUDIT TEKNIS KEAMANAN SISTEM INFORMASI SURAT TUGAS SEKOLAH VOKASI UNDIP Arkhan Subari; Saiful Manan; Eko Ariyanto; Adnan Fauzi
Gema Teknologi Vol 21, No 4 (2022): October 2021 - April 2022
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i4.46828

Abstract

An official travel assignment letter is a type of assignment letter needed by an employee in carrying out work assignments. In many ways, the assignment letter information system is built based on web-programming. In web-programming there are two methods to send data from client to server. The two methods are the POST method and the GET method. Information security is an important aspect that needs to be considered in design a information system. There are many attacker spying data on information system daily. Usually the attacker uses the loopholes in the data transmission method to attack the system. There are many techniques used to attack information systems likes WAVs (Web Application Security Scanners). WAVs is a program that is used to find security holes in web-based information systems using several methods, such as XSS, SQL Injection, Intercept and Bruteforce. One program that can be used is Burp Suite. Burp Suite is often used by security auditors, researchers, and testers for analysis of different systems. Burp's core functionality is to intercept and display HTTP requests in a structured manner. The Vocational School of Diponegoro University has developed an information system that is used to manage this assignment letter. The information system is design using a web-based application. However, the system has never been technically audited on its security level. Therefore, it is necessary to audit the information system security techniques so that the level of information system security can be ascertained and corrective steps can be taken if there are security holes found. This study is intended to conduct a technical audit of the security of the UNDIP Vocational School assignment letter information system. The audit was conducted using the WAVs (Web Application Security Scanners) method with the Burp Suite application. The results of the brutefoce test using Burpsuite showed that there was no suitable password. However, the fact that an attacker can attack 30,0006 times is a weakness that needs to be fixed.
Penerapan SCADA dan IoT Menggunakan PLC Sebagai Kontrol Motor AC untuk Pembelajaran Praktikum SMK Dadan Nurdin Bagenda; Noor Cholis Basjaruddin
Gema Teknologi Vol 21, No 3 (2021): April 2021 - October 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i3.42560

Abstract

The problem at the current Vocational High School that often arises is the unavailability of the Supervisory Control And Data Acquisition (SCADA) practicum module, to control AC Motor which can also be monitored online (IoT support) to support industry 4.0. The following solutions: (1). The developed module must be remotely controlled with industry standards; (2). The method used during the practicum is the problem-based-learning (PBL) method. To implement the above problem, a PLC that support SCADA and IoT (MQTT) was chosen. To introduce SCADA and IoT to students, we learned how to operating a simple industry-standard SCADA software and IoT (Ubidots). Post-training from the results of the questionnaire for vocational students, it was seen an average increase in knowledge of 56% compared to before training, a min 42% increase in PBL understanding, and a max 64% increase in knowledge of "Wonderware Intouch" as one of the Industry Standard SCADA
Rancang Bangun Sistem Monitoring Ketidakseimbangan Pembebanan Trafo Distribusi 3 Phase Menggunakan Arduino Mega Berbasis IoT Rama Alya Rozin Pintaka; Dista Yoel Tadeus
Gema Teknologi Vol 22, No 1 (2022): April 2022 - Oktober 2022
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i1.90243

Abstract

The load current in each phase does not have the same value, and the neutral current does not equal zero, which can result in power losses. This condition is caused by uneven load distribution across each phase during transformer operation, as well as differences in the operating times of consumer loads. Based on this situation, a load imbalance monitoring system was developed. The system utilizes the ESP-8266 Wemos D1 Mini Wi-Fi module to transmit sensor measurement data and provide warnings through the ThingSpeak website when load imbalance exceeds the applicable limit (>25% according to SPLN 12:1978). The data are obtained from measurements using the PZEM-004T sensor, with a measurement error ranging from 0.02–0.05%, and are then processed by an Arduino Mega 2560. When a load imbalance occurs, the microcontroller activates a buzzer and sends a warning notification to Twitter through the ThingSpeak website. Load control is performed manually by simulating different loads on each phase, resulting in the presence of neutral current.
Rancang Bangun Prototipe Robusta Coffee Bean Dryer Berbasis ESP32 Dengan Kontrol Suhu Otomatis dan Monitoring Melalui BLYNK Novi Chiquita Dewi Azizah; Yuniarto Yuniarto
Gema Teknologi Vol 23, No 1 (2024): April 2024 - October 2024
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v23i1.90330

Abstract

The coffee bean drying process is one of the post-harvest stages that affects bean quality, but conventional drying still depends on weather conditions and takes a relatively long time. This study aims to design and build a prototype ESP32-based Robusta coffee bean dryer with automatic temperature control and a monitoring system via Blynk. The system was designed using a modified 750 W electric oven as the drying chamber, an SHT30 sensor to measure temperature and relative humidity, an OLED display and a joystick as the local interface, and a Solid State Relay (SSR) to control the heating element. Temperature control is performed using the Proportional-Integral-Derivative (PID) method with parameters Kp = 1.5, Ki = 0, and Kd = 0.7 at a setpoint of 65°C. Temperature and humidity data are transmitted in real-time to Blynk via a Wi-Fi network and recorded in Google Sheets to support the monitoring and analysis process. Testing was conducted under two scenarios: drying using an oven with PID control at a setpoint of 65°C and conventional drying by sun-drying. The test results showed a rise time of 8 minutes with an overshoot of 4.62% (peak temperature of 68°C) and a steady-state average temperature of 64.58°C. The relative humidity in the drying chamber decreased from 93% to 19.8% in approximately 8 hours and 37 minutes. The results of the moisture content test using the gravimetric method showed a final moisture content of 12%, which meets the maximum limit of 12.5% based on SNI 01-2907-2008. In conventional testing, the sample mass decreased from 400 grams to 130.4 grams over seven days. These results indicate that the designed prototype is capable of performing the drying process with integrated temperature control and monitoring of the drying chamber conditions.
Rancang Bangun Sistem Peringatan Pergerakan Tanah Longsor Berbasis Mikrokontroler ESP32 Dan Transmisi LoRa Galih Argya Nugraha; Fakhruddin Mangkusasmito
Gema Teknologi Vol 22, No 3 (2023): April 2023 - October 2023
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i3.90299

Abstract

Landslides are one of the natural disasters that often occur in Indonesia, especially in highland areas and slopes with steep inclines. Landslides can cause serious impacts, such as loss of life, damage to infrastructure, and significant material losses. Indonesia, located in the equatorial region, has relatively high rainfall, which increases the potential for landslides, especially in areas that have experienced deforestation and unstable soil conditions. Therefore, a reliable early warning system that can quickly detect landslides is needed to reduce the risk of disasters. This study aims to design and build an ESP32 microcontroller-based landslide movement warning system with data communication support using LoRa technology. The system is designed using a mechanical pull switch sensor as an initial detector of ground movement. When the pull switch is pulled or disconnected, the ESP32 microcontroller will process the change in condition and immediately activate a siren and rotating light as an early warning at the location. The warning information is also sent to the receiving unit via the LoRa E220 module without relying on cellular networks or internet connections. The test results show that the system is able to respond quickly to ground movement and provide clear warnings. LoRa E220-900T22D communication can work well at an effective distance of up to ±900 meters in open areas. Based on these results, the designed system is considered simple, responsive, and suitable for implementation as an early warning system for landslides in disaster-prone areas with limited communication infrastructure.
Rancang Bangun Sistem Dispenser Earplug Otomatis Berbasis RFID RC522 Dan ESP32 Dengan Monitoring Melalui Website Dan Aplikasi Mobile Muhammad Wildan Hariansyah Putra; Arkhan Subari
Gema Teknologi Vol 21, No 4 (2022): October 2021 - April 2022
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i4.90287

Abstract

High noise levels in industrial environments can lead to hearing loss, necessitating the use of personal protective equipment (PPE) such as earplugs. However, excessive earplug usage beyond the daily quota often occurs, resulting in waste. To address this issue, an automatic earplug dispenser system was designed and built using RFID RC522 and ESP32, equipped with monitoring via a website and mobile application. This system aims to limit earplug dispensing per user according to the daily limit, automatically record usage data, and simplify distribution monitoring. Based on testing with four RFID cards, two registered (A and B) and two unregistered—the system successfully enforced the daily limit with a 100% success rate. Additionally, both the website and mobile application were proven to connect to the same database and display synchronized data in real time. Overall, the system effectively improves PPE management efficiency, reduces waste, and supports a more effective and well-monitored implementation of occupational health and safety (OHS) programs.

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