Ahmad Ashari
Departemen Ilmu Komputer dan Elektronika, FMIPA UGM, Yogyakarta

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Pengukuran Kecepatan Suara dalam Media Air Menggunakan Sensor Ultrasonik Miftakhul Khanan; Ahmad Ashari
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 10, No 1 (2020): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1029.451 KB) | DOI: 10.22146/ijeis.34829

Abstract

 The speed of sound in water varies depending on the condition. There are several factors that affect the difference in the speed of sound in water, such as the viscosity, temperature, pressure, etc. In this study, designed a tool to measure the speed of sound in water by utilizing ultrasonic waves.The ultrasonic sensor used consists of transmitter and receiver. The method used is indirect method by using sound reflection. The 40kHz ultrasonic wave used on the transmitter is generated by the AD9850 signal generator. Signals received receiver in and processed on a microcontroller through an LM393 comparator that makes the signal HIGH and LOW so it can be read directly on the digital pins of microcontroller.Measurements were made at a water temperature of 27oC with 1 meter test medium. The measurement is done on variation of distance from 5-90 cm with span of 5 cm. By knowing the time difference between the transmitted and received signal and the known wave range, the speed of sound in the water obtained in the study was (1394 ± 27) m / s with the determination coefficient of 0.998.
Penggunaan Metode Ontology Untuk Perancangan Purwarupa Sistem Smart Home Berbasis Context Aware Guntur Perdana; Ahmad Ashari
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 | Full PDF (597.766 KB) | DOI: 10.22146/ijeis.39042

Abstract

 Smart home system is a computer-aided system that will provide all comfort, safety, security and energy savings, which works automatically and programmed through a computer in a building or home. One of the method that can be used to design smart home is context aware method.  Context aware can work with the help of several other methods such as ontology method. Ontology has a variety of definition and always changes time by time. Ontology method is one of method that can process complex data. The ontology method allows complex reasoning and representation with better results. Constraints that are often encountered when designing a system that looks complex will face many problems such as many ambiguous domains. The existence of an ontology design before carrying out the prototype design of the smart home system will facilitate the smart home design process especially if the system will be made more complex so it would allows ambiguity from multiple domains. Testing with this ontology method is effective enough to minimize ambiguity from each domain, because each domain is designed with different characteristics. The results of the test concluded that the ontology design can be realized as a prototype of the smart home system.
Efisiensi Daya Pada Smartlock Bike-Sharing Berbasis LoRaWAN Dengan Metode GPS Duty Cycle Alfian Andi Nugroho; Ahmad Ashari
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 11, No 1 (2021): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijeis.57690

Abstract

Bike-sharing or commonly called Public-Use Bycycle (PUB), Bycycle Transit, or Smartbike is a short-term bicycle rental system that allows users to borrow bikes from a self-serve bike-sharing station to a point. Due to technological advances, the bike-sharing system that was once simple, now also utilizes technology in its operations. The modern bike-sharing system is equipped with IoT and GPS technology that is useful for sending data on the actual location of the bicycle, bicycle lock conditions, or even for M2M communication with other stations or bikes. However, this data transmission can cause the battery to run out quickly because of frequent sending and using GSM which requires a large enough power that is 200 mA when sending data and 80 mA when receiving, so that an alternative solution is needed to be able to save power. Therefore, the GPS Duty cycle is used as a method to increase power efficiency on the smartlock. In addition to using the GPS Duty cycle, this study also uses LoRa as a data delivery medium which has lower power usage compared to GSM technology. The results of this study are the duty-cycle algorithm can increase the efficiency of power usage up to 59% when compared to smartlocks that do not use the duty-cycle algorithm. It was also found that LoRa succeeded in sending data up to a distance of 750 meters with a successful delivery of 39.3 percent
Implementasi Basisdata Terdistribusi Pada Sistem Kenaikan Gaji Berkala Dinas Infokom Provinsi Maluku Anastasya Latubessy; Ahmad Ashari
IJCCS (Indonesian Journal of Computing and Cybernetics Systems) Vol 6, No 2 (2012): July
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijccs.2156

Abstract

AbstrakKemampuan socket yang bekerja pada komunikasi low level dalam melakukan transfer data antar aplikasi, diharapkan dapat diterapkan dalam sistem basis data terdistribusi. Beberapa alasan untuk membangun basis data terdistribusi adalah pemakaian bersama, kehandalan, ketersediaan, dan kecepatan pemrosesan query. Dengan pertimbangan tersebut, instansi-instansi baik pemerintah maupun swasta mulai tertarik untuk menggunakan sistem terdistribusi dalam pengelolaan pekerjaan pada instansinya. Hal ini dijadikan alasan untuk membangun sistem kenaikan gaji berkala otomatis di Dinas Informasi dan Komunikasi (Infokom) Provinsi Maluku. Selain itu, belum adanya sistem terkomputerisasi yang menangani sistem ini. Sistem kenaikan gaji berkala merupakan sistem yang bersifat kritis atau penting karena berhubungan dengan masalah uang, sehingga diperlukan juga sebuah sistem yang fault tolerant.Arsitektur sistem dibangun dengan metode client server yang memanfaatkan socket sebagai middleware dalam proses komunikasi pada jaringan. Menggunakan pendekatan full replica dengan pendekatan file replication using a group untuk menjamin konsistensi data. SQL Statement yang dikirimkan client akan diubah kedalam format XML yang kemudian akan dikirimkan ke kedua basisdata server menggunakan socket. Model redundansi data dan rendundansi proses diatur oleh middleware socket. Hasil yang diperoleh dalam penelitian ini adalah aplikasi socket sebagai middleware yang menangani distribusi data dari aplikasi web client ke basisdata server yang diimplementasikan pada sistem kenaikan gaji berkala otomatis di Dinas Infokom Provinsi Maluku.  Kata kunci— Socket, basisdata terdistribusi, client server AbstractSockets ability to transfer data between application  that work on the low level communication was expected to be implemented in a distributed database system. Some of the reasons for building a distributed database was data sharing, reliability, availability, and query processing speed. With these considerations, both government agencies and private sector became interested to use distributed systems to manage their job at the office. It is used as a reason to build an automated KGB system of Infokom Department in Province of Moluccas. Furthermore, there was no computerized system to handle this system before. Because of it was a critical or important system, then it was requires to build a system that has a fault tolerant capability.The system architecture was built by client server method using sockets as middleware in the process of network communicaton. The system method was used full replica, and used file replication using a group to ensure data consistency. The SQL Statement was sent by the client would be converted into an XML format which then would be sent to the server using a socket. Data redundancy model and process redundancy model managed by socket middleware.The results of this research was a middleware application using socket that handle the distribution of databases from client applications to database server that were implemented on a periodic system of automatic salary increases in the Office of Information and Communication in Province of Moluccas.  Keywords— Socket, distributed database, replication
Monitoring Ketinggian Air dan Curah Hujan Dalam Early Warning System Bencana Banjir Berbasis IoT Ivander Achmad Wandi; Ahmad Ashari
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) Vol 13, No 1 (2023): April
Publisher : IndoCEISS in colaboration with Universitas Gadjah Mada, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijeis.83569

Abstract

 Floods are natural disasters where there is an excessive volume of water that dampens the land. If left unchecked, flooding can bring disease, cause environmental damage and hinder people's mobility. Therefore, we need a system that can provide early warning to the community before a flood occurs. As technology develops, we can monitor the water level in an area to anticipate flooding. This concept is called the Early Warning System (EWS). IoT can help with real-time and continuous monitoring and warning of floods. IoT can also monitor air levels remotely. The MQTT protocol research also uses water level and rainfall sensors as data for flood detection. This system will detect water level and rainfall in real time. If the water level and rainfall reach a certain limit, the system will provide a warning to local residents via chatbot. There are 3 types of alerts in this system. Monitoring results are also displayed via the dashboard and sensor readings will be stored in the cloud database. The evaluation results show that the designed system can work well in providing flood early warning. Bots on Telegram have also sent notifications with an average delay of 0.561 seconds.