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TELKOMNIKA (Telecommunication Computing Electronics and Control)
Published by Universitas Ahmad Dahlan
ISSN : 16936930     EISSN : 23029293     DOI : 10.12928
Core Subject : Science,
Computer Science & IT
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)
Arjuna Subject : Ilmu Komputer (semua kategori) - Aplikasi Ilmu Komputer
Articles 2,614 Documents
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Determination of solid material permittivity using T-ring resonator for food industry Rammah A. Alahnomi; Z. Zakaria; Zulkalnain Mohd Yussof; Tole Sutikno; Amyrul Azuan Mohd Bahar; Ammar Alhegazi
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 1: February 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i1.11636

Abstract

In this paper, we present a simple design of a T-ring resonator sensor for characterizing solid detection.  The sensor is based on a planar microwave ring resonator and operating at 4.2 GHz frequency with a high-quality factor and sensitivity. An optimization of the T-ring geometry and materials were made to achieve high sensitivity for microwave material characterizations. This technique can determine the properties of solid materials from range of 2 GHz to 12 GHz frequencies. Techniques of current microwave resonator are usually measuring the properties of material at frequencies with a wide range; however, their accuracy is limited. Contrary to techniques that have a narrowband which is normally measuring the properties of materials to a high-accuracy with limitation to only a single frequency. This sensor has a capability of measuring the properties of materials at frequencies of wide range to a high-accuracy. A good agreement is achieved between the simulated results of the tested materials and the values of the manufacturer’s Data sheets. An empirical equation has been developed accordingly for the simulated results of the tested materials. Various standard materials have been tested for validation and verification of the sensor sensitivity. The proposed concept enables the detection and characterization of materials and it has miniaturized the size with low cost, reusable, reliable, and ease of design fabrication with using a small size of tested sample. It is inspiring a broader of interest in developing microwave planar sensors and improving their applications in food industry, quality control and biomedical materials.
Cooperative underlay cognitive radio assisted NOMA: secondary network improvement and outage performance Dinh-Thuan Do; Chi-Bao Le; Anh-Tu Le
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i5.12451

Abstract

In this paper, a downlink scenario of a non-orthogonal multiple access (NOMA) scheme with power constraint via spectrum sensing is considered. Such network provides improved outage performance and new scheme of NOMA-based cognitive radio (CR-NOMA) network are introduced. The different power allocation factors are examined subject to performance gap among these secondary NOMA users. To evaluate system performance, the exact outage probability expressions of secondary users are derived. Finally, the dissimilar performance problem in term of secondary users is illustrated via simulation, in which a power allocation scheme and the threshold rates are considered as main impacts of varying system performance. The simulation results show that the performance of CR-NOMA network can be improved significantly.
Design of freeform lens for WLEDs on the fishing boat Nguyen Thi Phuong Loan; Thinh Cong Tran
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 3: June 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i3.12085

Abstract

In this article, a free secondary lens is designed for an LED fishing/working lamp (LFWL), which is recommended for the purpose of taking the place of a traditional high-intensity discharge (HID) fishing lamp. To serve the lighting needs of fishing and the on-board activities on fishing boats, the innovative LED lamp is proposed. To make the freeform lens in our optics design process, we depended on Gaussian decomposition. In this way, it is easy to approach the targeted light intensity distribution curve (LIDC) of the LFWL lens. The simulated results show that the performance of the LED fishing/working lamps is much better than that of HID fishing lamps for illumination onboard, on the sea-surface, and underwater. Meanwhile, a lighting efficiency of 91% with the power consumption reduction of more than 50% can be achieved when the proposed LED fishing/working lamps are used instead of the HID fishing lamps.
Excellent color quality of phosphor converted white light emitting diodes with remote phosphor geometry Thinh Cong Tran; Nguyen Doan Quoc Anh; Nguyen Thi Phuong Loan
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 5: October 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i5.13575

Abstract

The remote phosphor structure is disadvantageous in color quality but more convenient in luminous flux when compared to conformal phosphor or in-cup phosphor structure. From this disadvantage, there are many studies to improve the color quality of the remote phosphor structure. This research will propose a dual-layer remote phosphor structure to improve color rendering index (CRI) and color quality scale (CQS) of WLEDs. The WLED package with color temperature of 8500 K is utilized in this study. The idea of the study is to locate a layer of phosphor green Y2O2S:Tb3+ or red ZnS:Sn2+ on the yellow phosphor YAG:Ce3+ film, and then finding the suitable added concentration of ZnS:Sn2+ to match the highest color quality. The results showed that ZnS:Sn2+ brings great benefits to increase CRI and CQS. The greater the ZnS:Sn2+ concentration is, the higher the CRI and CQS become owing to the rise in red light components in WLEDs. Meanwhile, the green Y2O2S:Tb3+ phosphor brings benefits to luminous flux. However, the decrease in luminous flux and color quality occurs when the concentration of ZnS:Sn2+ and Y2O2S:Tb3+ exceeds the corresponding level. This is proved by applying Mie-scattering theory and Lambert-Beer's law. The results of articles are important for WLEDs’ fabrication having higher white light quality.
The Digital Microscope and Its Image Processing Utility Sri Hartati; Agus Harjoko; Tri Wahyu Supardi
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 3: December 2011
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v9i3.749

Abstract

Many institutions, including high schools, own a large number of analog or ordinary microscopes. These microscopes are used to observe small objects. Unfortunately, object observations on the ordinary microscope require precision and visual acuity of the user. This paper discusses the development of a high-resolution digital microscope from an analog microscope, including the image processing utility, which allows the digital microscope users to capture, store and process the digital images of the object being observed. The proposed microscope is constructed from hardware components that can be easily found in Indonesia. The image processing software is capable of performing brightness adjustment, contrast enhancement, histogram equalization, scaling and cropping. The proposed digital microscope has a maximum magnification of 1600x, and image resolution can be varied from 320x240 pixels up to 2592x1944 pixels. The microscope was tested with various objects with a variety of magnification, and image processing was carried out on the image of the object. The results showed that the digital microscope and its image processing system were capable of enhancing the observed object and other operations in accordance with the user need. The digital microscope has eliminated the need for direct observation by human eye as with the traditional microscope.
Weed Control Decision Support System Based on Precision Agriculture Approach Rizky Mulya Sampurno; Kudang Boro Seminar; Yuli Suharnoto
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 12, No 2: June 2014
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v12i2.62

Abstract

Herbicides have been widely used for weed control in modern agriculture. However the use of herbicides is potentialy introducing negative impact to the environment due to excessive use of herbicides. Based on precision agriculture principles, unique and precise treatment of herbicide supply for a particular area for crop production must be performed. The objective of this research is to develop a decision support system (DSS) for schedulling of weed spraying and for selecting the proper nozzle size of the sprayers that introduce minimum negative impact to the environment. The main set of data required for our proposed system includes the set of 10 years weather data series acquired from remote sensing (NOAA and TRMM) and a set of vegetation index from MODIS EVI. The weather data set is utilized to determine the planting time period of paddy crop and to determine the proper size of the sprayers for weed spraying. Our DSS prototype has been implemented and tested with real data set in Jonggol district, West Java, Indonesia. The implementation, testing results, and future enhancement of our system are discussed in this paper.
Optimization of Sensor Network Topology in Deployed in Inhomogeneous Lossy Media Rony Teguh; Hajime Igarashi
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 13, No 2: June 2015
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v13i2.961

Abstract

This paper presents optimization of wireless sensor network (WSN) topology for forest fire detection. The sensors for this purpose are deployed in forest, grassland and open space, which have different attenuation properties in electromagnetic waves. For this reason, routers which receive signals from sensors and send them to the base station must be deployed considering these differences. In this work, we develop an optimization method for WSN topology based on simulated annealing considering the differences in the attenuation property. The vegetation data are taken from Landsat data. Using the present method, the necessary number of routers for full connection of the sensors deployed in diverse, irregular environments can be estimated.
Prediction Model of Smelting Endpoint of Fuming Furnace Based on Grey Neural Network Song Qiang; WU Yaochun
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 14, No 3: September 2016
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v14i3.3713

Abstract

Since grey theory and neural network could improve prediction precision, the technology of combination prediction was proposed in this study. Then the algorithm was simulated by Matlab using practical data of a fuming furnace. The results reveal that the smelting endpoint of fuming furnace could be accurately predicted with this model by referring to small sample and information. Therefore, GNN model is effective with the advantages of high precision, fewer samples required and simple calculation.
Weighted Least Squared Approach to Fault Detection and Isolation for GPS Integrity Monitoring Ershen Wang; Fuxia Yang; Pingping Qu; Tao Pang; Xiaoyu Lan
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 3: September 2017
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v15i3.5800

Abstract

Reliability of a global navigation satellite system is one of great importance for global navigation purposes. Therefore, an integrity monitoring system is an inseparable part of aviation navigation system. Failures or faults due to malfunctions in the systems should be detected to keep the integrity of the system intact. In order to solve the problem that least squares method detects and isolates a satellite fault for GPS integrity monitoring, in this paper, a weighted least squares algorithm is proposed for satellite fault detection and isolation. The algorithm adopts the diagonal elements of the covariance matrix of GPS measurement equation as the weighted factor. Firstly, the weighted least squares approach for satellite fault detection establishes the test statistic by the sum of the squares of the pseudo-range residuals of each satellite for GPS. Then, the detection threshold is obtained by the false alarm rate of the fault detection, probability density function and visiable satellite number.The effectiveness of the proposed approach is illustrated in a problem of GPS (Global Positioning System) autonomous integrity monitoring system. Through the real raw measured GPS data，based on least squares RAIM method and the weighted least squares RAIM approach, the performance of the two algorithms is compared. The results show that the proposed RAIM approach is superior to the least squares RAIM algorithm in the sensitivity of fault detection and fault isolation performance for GPS integrity monitoring.
Probabilistic Self-Organizing Maps for Text-Independent Speaker Identification Ayoub Bouziane; Jamal Kharroubi; Arsalane Zarghili
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 1: February 2018
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v16i1.7559

Abstract

The present paper introduces a novel speaker modeling technique for text-independent speaker identification using probabilistic self-organizing maps (PbSOMs). The basic motivation behind the introduced technique was to combine the self-organizing quality of the self-organizing maps and generative power of Gaussian mixture models. Experimental results show that the introduced modeling technique using probabilistic self-organizing maps significantly outperforms the traditional technique using the classical GMMs and the EM algorithm or its deterministic variant. More precisely, a relative accuracy improvement of roughly 39% has been gained, as well as, a much less sensitivity to the model-parameters initialization has been exhibited by using the introduced speaker modeling technique using probabilistic self-organizing maps.

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