TELKOMNIKA (Telecommunication Computing Electronics and Control)
Submitted papers are evaluated by anonymous referees by single blind peer review for contribution, originality, relevance, and presentation. The Editor shall inform you of the results of the review as soon as possible, hopefully in 10 weeks. Please notice that because of the great number of submissions that TELKOMNIKA has received during the last few months the duration of the review process can be up to 14 weeks. Communication Engineering, Computer Network and System Engineering, Computer Science and Information System, Machine Learning, AI and Soft Computing, Signal, Image and Video Processing, Electronics Engineering, Electrical Power Engineering, Power Electronics and Drives, Instrumentation and Control Engineering, Internet of Things (IoT)
Articles
2,614 Documents
Low cost NodeMcu based development water rocket measurement system applied to STEM education
Andi Susilo;
Yasmiati Yasmiati;
Ahmad Apandi
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 3: June 2019
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v17i3.12227
Water rockets have become one of learning tools for STEM Education in schools. Generally water rockets make in school activity have no parachute load, altitude, and velocity measurement. Rocket can go any direction and also will cause hard collision to the ground that break the high speed rocket. It will take time and need more cost to make a new one for students. This study propose the low cost NodeMcu based water rocket measurement system to solve the problem. Altitude and velocity measurement are added and deployment system to release the parachute to make water rocket fall to the ground smoothly. Smartphone application used to monitor altitude and velocity of water rocket. Variables consist of water volume and air pressure. Five experiments had been conducted and recorded. The result found that the system could calculate Altitude, Velocity, and Deployment System also could release the parachute automatically in Coasting Descent position.
Implementation smart home using internet of things
Afrizal Mayub;
Fahmizal Fahmizal;
Ma’ruf Shidiq;
Unan Yusmaniar Oktiawati;
Nur Rohman Rosyid
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 6: December 2019
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v17i6.11722
Development in technology of information today provides various facilities to support human activity. One technology that facilitates human is the use of automated systems, the application of smart home system makes it easier for users to control household electronic devices. This study addresses one of the smart home solutions with automation systems. The system is built using ESP8266 and Raspberry Pi devices, by utilizing MQTT, REST and Laravel framework protocols. With Arduino, Python and PHP programming, household devices can be controlled both automatically and manually. Control system can be done by using web, chatbot, and physically. The communication used utilizes wireless network. With the designed system, the users can control the device, gain information and get warning. The information provided by the system is obtained from open data on the internet and from the sensor installed on the device.
Na3Ce(PO4)2:Tb3+ and Na(Mg2–xMnX)LiSi4O10F2:Mn phosphors: a suitable selection for enhancing color quality and luminous flux of remote white light-emitting diodes
Nguyen Thi Phuong Loan;
Nguyen Doan Quoc Anh
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 4: August 2020
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v18i4.13723
This study proposed the TRP, a remote phosphor structure that has 3 phosphor layers, to ehance the chromatic quality and lumen output for white light-emitting diodes devices (WLEDs). The arrangment of phosphor layers is yellow YAG:Ce3+ phosphor, green Na3Ce(PO4)2:Tb3+ phosphor, and red Na(Mg2–xMnX)LiSi4O10F2:Mn phosphor from bottom to top. Red Na(Mg2–xMnX)LiSi4O10F2:Mn phosphor is used for the red light component to boost color rendering index (CRI). The green layer Na3Ce(PO4)2:Tb3+ phosphor is utilized for the green light component to produce higher luminous flux (LF). With the addition of red and green phosphor, the yellow YAG:Ce3+ concentration must decrease to maintain the 6000 K color temperature. The research results show that red phosphor Na(Mg2–xMnX)LiSi4O10F2:Mn concentration is beneficial for CRI, while green phosphor Na3Ce(PO4)2:Tb3+ is detrimental to CRI. Morever, CQS reaction with red and green phosphor is also studied, which show notable improvement when Na(Mg2–xMnX)LiSi4O10F2:Mn concentration is from 10%-14%, regardless of Na3Ce(PO4)2:Tb3+. The luminous flux (LF) can also increase for more than 40% with the reduced light loss and added green phosphor. Research results are valuable references for producers to enhance the color quality and the light emission of WLEDs.
Distributed optimal congestion control and channel assignment in wireless mesh networks
D. Jasmine David;
V. Jegathesan;
T. Jemima Jebaseeli
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 19, No 2: April 2021
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v19i2.16135
Wireless mesh networks have numerous advantages in terms of connectivity as well as reliability. Traditionally the nodes in wireless mesh networks are equipped with single radio, but the limitations are lower throughput and limited use of the available wireless channel. In order to overcome this, the recent advances in wireless mesh networks are based on multi-channel multi-radio approach. Channel assignment is a technique that selects the best channel for a node or to the entire network just to increase the network capacity. To maximize the throughput and the capacity of the network, multiple channels with multiple radios were introduced in these networks. In the proposed system, algorithms are developed to improve throughput, minimise delay, reduce average energy consumption and increase the residual energy for multi radio multi-channel wireless mesh networks. In literature, the existing channel assignment algorithms fail to consider both interflow and intra flow interferences. The limitations are inaccurate bandwidth estimation, throughput degradation under heavy traffic and unwanted energy consumption during low traffic and increase in delay. In order to improve the performance of the network distributed optimal congestion control and channel assignment algorithm (DOCCA) is proposed. In this algorithm, if congestion is identified, the information is given to previous node. According to the congestion level, the node adjusts itself to minimise congestion.
Sparse Representation for Detection of Microcalcification Clusters
Xinsheng Zhang;
Minghu Wang;
Ji Ma Ji Ma
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 10, No 3: September 2012
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v10i3.835
We present an approach to detect MCs in mammograms by casting the detection problem as finding sparse representations of test samples with respect to training samples. The ground truth training samples of MCs in mammograms are assumed to be known as a priori. From these samples of the interest object class, a vocabulary of information-rich object parts is automatically constructed. The sparse representation is computed by the l1-regularized least square approach using the interior-point method. The method based on sparse representation expresses each testing sample as a linear combination of all the training samplesfrom the vocabulary. The sparse coefficient vector is obtained by l1-regularized least square through learning. MCs detectionis achieved by defining discriminatefunctions from the sparse coefficient vector for each category. To investigate its performance, the proposed method is applied to DDSM datasets and compared with support vector machines (SVMs) and twin support vector machines (TWSVMs). The experimental results have shown that the performance of the proposed method is comparable with or better than those methods. In addition, the proposed method is more efficient than SVMs and TWSVMs based methods as it has no need of model selection and parameter optimization.
A NOVEL APPROACH FOR CONFIGURING THE STIMULATOR OF A BCI FRAMEWORK USING XML
Indar Sugiarto
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 7, No 2: August 2009
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v7i2.579
In a working BCI framework, all aspects must be considered as an integral part that contributes to the successful operation of a BCI system. This also includes the development of robust but flexible stimulator, especially the one that closely related to the feedback of a BCI system. This paper describes a novel approach in providing flexible visual stimulator using XML which has been applied for a BCI (brain-computer interface) framework. Using XML file format for configuring the visual stimulator of a BCI system, we can develop BCI applications which can accommodate many experiment strategies in BCI research. The BCI framework and its configuration platform is developed using C++ programming language which incorporate Qt’s most powerful XML parser named QXmlStream. The implementation and experiment shows that the XML configuration file can be well executed within the proposed BCI framework. Beside its capability in presenting flexible flickering frequencies and text formatting for SSVEP-based BCI, the configuration platform also provides 3 shapes, 16 colors, and 5 distinct feedback bars. It is not necessary to increase the number of shapes nor colors since those parameters are less important for the BCI stimulator. The proposed method can then be extended to enhance the usability of currently existed BCI framework such as BF++ Toys and BCI 2000.
Research of NiMH Battery Modeling and Simulation Based on Linear Regression Analysis Method
Chang-hao Piao;
Qing-yong Qin;
Qian Zhang;
Yong-sheng Zhang
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 11, No 4: December 2013
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v11i4.1154
The battery state-of-charge estimation was one of core issues in the development of electric vehicles battery management system, and higher accurate model was needed in state-of-charge estimation correctly. Therefore, accurate battery modeling and simulation was researched here. The Thevenin equivalent circuit model of NiMH battery was established for the poor accuracy of traditional model. Based on the data which were brought from the 6V 6Ah NiMH battery hybrid pulse cycling test experiments, Thevenin model parameters were identified by means of the linear regression analysis method. Then, the battery equivalent circuit simulating model was built in the MATLAB/Simulink environment. The simulation and experimental results showed that the model has better accuracy and can be used to guide the battery state-of-charge estimation.
Simplified Linear Configuration Model of 3X3 Single Mode Fiber Coupler using Matrix Transfer
Saktioto Saktioto;
Dedi Irawan;
Defrianto Defrianto
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 13, No 3: September 2015
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v13i3.2094
Experimental design and operation of a directional fiber coupler having identical-output ratio is successfully fabricated. The coupling region is imposed by fusion temperature 800-1350 0C injecting the Hydrogen gas at 1Atm. Concurrently the coupled-mode theory is used to model power transfer between the waveguides by using transfer matrix method. By 1mW source input power to one of three input ports, it shows that power propagation among three coupled fibers is normalized; the optical fiber are nearly identical and a similar separation between them. The matrix configuration of 3X3 is also used to calculate the polarization effect of directional fiber coupler. It is found that the incident power polarized with various angle causes power output at both three output ports decrease exponentially. This 3X3 directional fiber coupler design is a significant passive component for various functions power splitter and routers.
Design of Single-Stage Flyback PFC Converter for LED Driver
Wang Qi;
Wu Jie;
Baohua Lang
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 14, No 4: December 2016
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v14i4.3966
A light emitting diode (LED) driver based on single-stage power factor correction (PFC) is presented in this paper. The designed LED driver using flyback topology can achieve power factor correction and constant-current drive LED in boundary conduction mode. The circuit principle is described in detail, the formulas for MOS switch-on time, switching frequency and the main impact factor of power factor are proposed. The experiment results show that the designed LED driver has high power factor, stable output and it can drive the LED with high efficiency.
Investigating Maturity State and Internal Properties of Fruits Using Non-destructive Techniques-a Review
Mohd Fadzli Abd Shaib;
Ruzairi Abdul Rahim;
S. Z. M. Muji;
Azian Abd Aziz Ahmad
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 4: December 2017
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v15i4.7236
The evaluation of internal condition of the fruit via destructive techniques mostly damaged the internal and external fruit structure. However, there are several non-destructive techniques available could be applied in the agricultural industry, specifically for observing internal fruit conditions. Different kinds of internal conditions of fruits are evaluated in terms of their quality and ripeness levels. These non-destructive techniques include fruit evaluation via ultrasonic measurement techniques, light spectroscopy, imaging via Magnetic Resonance Imaging (MRI) and X-Ray, computer vision, electric nose and also vibration. The capabilities and the effectiveness of these techniques towards fruit monitoring are thoroughly discussed. Besides, the drawback of these non-destructive technique has been analysed.