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29,758 Article Results

Area & Power Efficient VLSI Architecture of Mode Decision in Integer Motion Estimation for HEVC Video Coding Standard

10.11591/ijece.v9i4.pp2469-2480
EL Ansari Abdessamad , Nejmeddine Bahri , Anass Mansouri , Nouri Masmoud , Ahaitouf Ali
In this paper, we propose a new parallel hardware architecture for the mode decision algorithm, that it is based on the Sum Absolute of the Difference (SAD) for compute the motion estimation, which is the most critical algorithm in the recent video encoding standard HEVC. In fact, this standard introduced new large variable block sizes for the motion estimation algorithm and therefore the SAD requires a more reduced execution time in order to achieve the real time processing even for the ultra-high resolution sequences. The proposed accelerator executes the SAD algorithm in a parallel way for all sub-block prediction units (PUs) and coding unit (CU) whatever their sizes, which turns in a huge improvements in the performances, given that all the block sizes, PUs in each CU, are supported and processed in the same time. The Xilinx Artix-7 (Zynq-7000) FPGA is used for the prototyping and the synthesis of the proposed accelerator. The mode decision for motion estimation scheme is implemented with 32K LUTs, 50K registers and 108Kb BRAMs. The implementation results show that our hardware architecture can achieve 30 frames per second of the 4K (3840 × 2160) resolutions in real time processing at 115.15MHz.
Volume: 9
Issue: 4
Page: 2469-2480
Publish at: 2019-08-01

Clustering and data aggregation scheme in underwater wireless acoustic sensor network

10.12928/telkomnika.v17i4.11379
Vani; REVA University Krishnaswamy , Sunil Kumar S.; REVA University Manvi
Underwater Wireless Acoustic Sensor Networks (UWASNs) are creating attentiveness in researchers due to its wide area of applications. To extract the data from underwater and transmit to watersurface, numerous clustering and data aggregation schemes are employed. The main objectives of clustering and data aggregation schemes are to decrease the consumption of energy and prolong the lifetime of the network. In this paper, we focus on initial clustering of sensor nodes based on their geographical locations using fuzzy logic. The probability of degree of belongingness of a sensor node to its cluster, along with number of clusters is analysed and discussed. Based on the energy and distance the cluster head nodes are determined. Finally using using similarity function data aggregation is analysed and discussed. The proposed scheme is simulated in MATLAB and compared with LEACH algorithm. The simulation results indicate that the proposed scheme performs better in maximizing network lifetime and minimizing energy consumption.
Volume: 17
Issue: 4
Page: 1604-1614
Publish at: 2019-08-01

Minimizing harmonic distortion impact cause by CS using meta heuristic technique

10.12928/telkomnika.v17i4.12768
S. N. Syed; Universiti Teknologi Malaysia Nasir , J. J.; Universiti Teknologi Malaysia Jamian , M. W.; Universiti Teknologi Malaysia Mustafa
Non-linear load in the distribution system has caused negative impact to its power quality especially on harmonic distortion. Charging Station (CS) is a non-linear load that widely promoted with the aim to support the continuous usage of Electric Vehicle (EV). This research is focusing on optimal placement and sizing of multiple passive filter to mitigate harmonic distortion due to CS usage at distribution system. There are 6 units of CS which being placed in low voltage buses which indirectly will inject harmonic to the system during charging. Power system harmonic flow, passive filter, CS, battery and the analysis will be model in MATLAB. Multi-objective function which are weight summation approach (WSA) and Pareto Front are used to assist meta heuristic technique which is Modified Lightning Search Algorithm (MLSA) to identify optimum location and sizing of passive filter based on improvement on propose five parameters. From the result, the optimal placements and sizing of passive filter able to reduce the maximum Total Harmonic Distortion (THD) for voltage, current and apparent losses respectively. Therefore, the propose method is suitable to reduce harmonic distortion as well as apparent losses at distribution system with present of CS.
Volume: 17
Issue: 4
Page: 1992-2000
Publish at: 2019-08-01

A total variation-undecimated wavelet approach to chest radiograph image enhancement

10.12928/telkomnika.v17i4.11911
Matilda; University of Ghana Wilson , James B. H.; Kwame Nkrumah University of Science and Tech Acquah , Anthony Y.; Eastern Connecticut State University Aidoo
Most often medical images such as X-Rays have a low dynamic range and many of their targeted features are difficult to identify. Intensity transformations that improve image quality usually rely onwavelet denoising and enhancement typically use the technique of thresholding to obtain better quality medical images. A disadvantage of wavelet thresholding is that even though it adequately removes noise in an image, it introduces unwanted artifacts into the image near discontinuities. We utilize a total variation method and an undecimated wavelet image enhancing algorithm for improving the image quality of chest radiographs. Our approach achieves a high level chest radiograph image deniosing in lung nodules detection while preserving the important features. Moreover, our method results in a high image sensitivity that reduces the average number of false positives on a test set of medical data.
Volume: 17
Issue: 4
Page: 2116-2124
Publish at: 2019-08-01

An Efficient Microcontroller Based Sun Tracker Control for Solar Cell Systems

10.11591/ijece.v9i4.pp2743-2750
E.M.H. Arif , J. Hossen , G. Ramana Murthy , Jesmeen M. Z. H. , J. Emerson Raja
The solar energy is fast becoming a different means of electricity resource. Now in world Fossil fuels are seriously depleting thus the need for another energy source is a necessity. To create effective utilization of its solar, energy efficiency must be maximized. An attainable way to deal with amplifying the power output of sun-powered exhibit is by sun tracking. This paper presents the control system for a solar cell orientation device which follows the sun in real time during daytime.
Volume: 9
Issue: 4
Page: 2743-2750
Publish at: 2019-08-01

5G beam-steering 2×2 butler matrix with slotted waveguide antenna array

10.12928/telkomnika.v17i4.12777
Noorlindawaty Md.; Multimedia University Jizat , Nazihah; Multimedia University Ahmad , Zubaida; Multimedia University Yusoff , Nuramirah Mohd; Mindmatics Sdn. Bhd. Nor , Mursyidul Idzam; Mindmatics Sdn. Bhd. Sabran
In this research paper, substrate integrated waveguide (SIW) was proposed as a technique by realizing bilateral edge walls to produce a compact 5G beam-steering antenna at 24 GHz. The beam forming network is produced using SIW directional coupler perform as 2×2 Butler Matrix (BM) fed with SIW slotted waveguide antenna array. The output signal is steered from -29 degrees and +29 degrees when the signal is fed to the respective input ports. If one of the input ports is fed, the signal is evenly distributed between the adjacent output ports with 90 degree constant phase shift. The compact size of directional coupler was designed by longitude slots on the surface of SIW substrate with bandwith of 16.85% at the operating frequency. The proposed antenna produce gain of 6.34 dB at operating frequency and the promising outcome of the beam steering make proposed design suitable for 5G communications especially with tracking capabilities.
Volume: 17
Issue: 4
Page: 1656-1662
Publish at: 2019-08-01

Imperceptible and secure image watermarking using DCT and random spread technique

10.12928/telkomnika.v17i4.9227
Eko Hari; Dian Nuswantoro University Rachmawanto , De Rosal Ignatius Moses; Dian Nuswantoro University Setiadi , Christy Atika; Dian Nuswantoro University Sari , Nova; Dian Nuswantoro University Rijati
Watermarking is a copyright protection technique, while cryptography is a message encoding technique. Imperceptibility, robustness, and safety are aspects that are often investigated in watermarking. Cryptography can be implemented to increase watermark security. Beaufort cipher is the algorithm proposed in this research to encrypt watermark. The new idea proposed in this research is the utilization of Beaufort key for watermark encryption process as well as for spread watermark when inserted as PN Sequence substitute with the aim to improve imperceptibility and security aspects. Where PN Sequence is widely used in spread spectrum watermarking technique. Based on the experimental results and testing of the proposed method proved that imperceptibility and watermark security are increased. Improved imperceptibility measured by PSNR rose by about 5dB and so did the MSE score better. Robustness aspect is also maintained which has been proven by the excellent value of NCC.
Volume: 17
Issue: 4
Page: 1750-1757
Publish at: 2019-08-01

The statistical analysis of random-valued impulse noise detection techniques based on the local image characteristic: ROAD, ROLD and RORD

10.11591/ijeecs.v15.i2.pp794-803
Vorapoj Patanavijit , Kornkamol Thakulsukanant
Advances in local image statistical analysis have made possible the random-valued impulse noise detection but the current noise detections based on ROAD (Rank-Ordered Absolute Differences), ROLD (Rank-Ordered Logarithmic Differences) and RORD (Rank-Ordered Relative Differences), which are the most three effective and practical detections using the local image statistical characteristic, operates effectively on different noise density and different image statistical characteristic. To address these issues, this paper proposes the comparative analysis on the noise detections based on ROAD, ROLD and RORD. Therefore, the first contribution is the comparative statistical distribution of these three noise detections. By comprehensive experiment at each noise density, the optimized detected threshold is later determined from four benchmark data: Lena, Girl, Pepper and Airplane. Moreover, the maximum detection accuracy for each case is comparatively demonstrated by using the noise detections based on ROAD, ROLD and RORD with the optimized detected threshold.
Volume: 15
Issue: 2
Page: 794-803
Publish at: 2019-08-01

Optical sensor based on dye-sensitized solar cell with tobacco chlorophyll

10.12928/telkomnika.v17i4.12613
Eka; Brawijaya University Maulana , Rahmadwati; Brawijaya University Rahmadwati , Sapriesty Nainy; Brawijaya University Sari , Akhmad; Brawijaya University Sabarudin
Modified optical sensor based on dye-sensittized solar cell has been successfully fabricated to measure the number of light energy. The electric parameters as the sensor output were achieved from the light illuminance as the sensor input. The measured parameter from optical sensor according to the voltage and current output have been characterized to obtain the sensor performance. In this research, the modified sensor is customized from dye-sensitized solar cell with extracted tobacco chlorophyll dye as the photo-catalysator, photo-electrode of titanium dioxide and Iodine solution for redox reaction. The thick layer deposition with selected material is conducted using spin coating method of 1000 rpm. Based on the absorbance measurement, it shows that tobacco dye has the characteristics of visible light absorption in the wavelength of visible light spectra. The analytical result shows that the sensor has the wide linear characteristic in certain light illuminance and the increasing light intensity produces higher electrical parameter output both current and voltage. This sensor has potential prospect to be used as a light sensor and to be competitive fabrication cost.
Volume: 17
Issue: 4
Page: 1907-1913
Publish at: 2019-08-01

Ternary content addressable memory for longest prefix matching based on random access memory on field programmable gate array

10.12928/telkomnika.v17i4.11000
Ng Shao; Universiti Teknologi Malaysia Kay , M. N.; Universiti Teknologi Malaysia Marsono
Conventional ternary content addressable memory (TCAM) provides access to stored data, which consists of '0', '1' and ‘don't care’, and outputs the matched address. Content lookup in TCAM can be done in a single cycle, which makes it very important in applications such as address lookup and deep-packet inspection. This paper proposes an improved TCAM architecture with fast update functionality. To support longest prefix matching (LPM), LPM logic are needed to the proposed TCAM. The latency of the proposed LPM logic is dependent on the number of matching addresses in address prefix comparison. In order to improve the throughput, parallel LPM logic is added to improve the throughput by 10× compared to the one without. Although with resource overhead, the cost of throughput per bit is less as compared to the one without parallel LPM logic.
Volume: 17
Issue: 4
Page: 1882-1889
Publish at: 2019-08-01

Graphene field-effect transistor simulation with TCAD on top-gate dielectric influences

10.12928/telkomnika.v17i4.12760
Muhamad Amri; MIMOS Semiconductor (M) Sdn Ismail , Khairil Mazwan Mohd; MIMOS Semiconductor (M) Sdn Zaini , Mohd Ismahadi; MIMOS Semiconductor (M) Sdn Syono
This paper presents the influence of top-gate dielectric material for graphene field-effect transistor (GFET) using TCAD simulation. Apart from silicon-based dielectric that is typically used for top-gate structure, other high-dielectric constant (high-k) dielectric materials namely aluminum oxide and hafnium oxide are also involved in the analysis deliberately to improve the electrical properties of the GFET. The unique GFET current-voltage characteristics against several top-gate dielectric thicknesses are also investigated to guide the wafer fabrication engineers during the process optimization stage. The improvement to critical electrical parameters of GFET in terms of higher saturation drain current and greater on/off current ratio shows that the use of high-k dielectric material with very thin oxide layer is absolutely necessary.
Volume: 17
Issue: 4
Page: 1845-1852
Publish at: 2019-08-01

Design of single phase inverter for photovoltaic application controlled with sinusoidal pulse width modulation

10.11591/ijeecs.v15.i2.pp620-630
Ibrahim Alhamrouni , N. Zainuddin , Mohamed Salem , Nadia H. A. Rahman , Lili Awalin
The application of fossil fuels likes coal, oil and gas gives the enormous environmental impact and hazardous effects to the earth. Hence, renewable energy has become the most tremendously friendly methods to generate the electricity without pollution and emissions. Inverter is a power electronics device which is used to convert Direct Current (DC) into Alternating Current (AC). The conventional inverter no longer fulfills the requirement of reducing harmonic distortions plus it causes global warming and greenhouse effect. For increasing the efficiency and reliability of the system, the PV inverter becomes a vital part in the conversion of DC to AC output. This research thus presents a single phase photovoltaic inverter controlled with sinusoidal pulse-width-modulation (SPWM) and low pass filter connection between the inverter and the utility grid to reduce the harmonics due to intermittent nature of the renewable energy sources. Unipolar and Bipolar switching scheme are applied to control the magnitude and frequency of output voltage and result of both unipolar and bipolar are compared. The simulation of the proposed technique is executed by using Matlab/Simulink.
Volume: 15
Issue: 2
Page: 620-630
Publish at: 2019-08-01

Channel length scaling and electrical characterization of graphene field effect transistor (GFET)

10.11591/ijeecs.v15.i2.pp697-703
Reena Sri Selvarajan , Azrul Azlan Hamzah , Norliana Yusof , Burhanuddin Yeop Majlis
The exclusive monoatomic framework of graphene makes it as an alluring material to be implemented in electronic devices. Thus, using graphene as charge carrying conducting channel material in Field Effect Transistors (FET) expedites the opportunities for production of ultrasensitive biosensors for future device applications. However, performance of GFET is influenced by various parameters, particularly by the length of conducting channel. Therefore, in this study we have investigated channel length scaling in performance of graphene field effect transistor (GFET) via simulation technique using Lumerical DEVICE software. The performance was analyzed based on electrical characterization of GFET with long and short conducting channels. It proves that conducting channel lengths have vast effect on ambipolar curve where short channel induces asymmetry in transfer characteristics curve where the n-branch is suppressed. Whereas for output characteristics, the performance of GFET heavily degraded as the channel length is reduced in short channels of GFET. Therefore, channel length scaling is a vital parameter in determining the performance of GFET in various fields, particularly in biosensing applications for ultrasensitive detection.
Volume: 15
Issue: 2
Page: 697-703
Publish at: 2019-08-01

Novel design and analysis of RF MEMS shunt capacitive switch for radar and satellite communications

10.11591/ijeecs.v15.i2.pp971-978
Maham Kamil Naji , Alaa Desher Farhood , Adnan Hussein Ali
In this paper, a new type of Radio Frequency Micro-Electro-Mechanical System (RF-MEMS) shunt capacitive switch is designed and studied. RF MEMS switch has a number of advantages in a modern telecommunication system such as low power consumption, easy to fabricate and power handling capacity at radio frequency. At high frequency applications, this switch shows very superior performance due to which it now became one of the key elements for RF application. In this proposed design, an innovative type of MEMS switch is designed. The MEMS switch structure consists of substrate, co-planar waveguide (CPW), dielectric material and a metallic bridge. The proposed MEMS switch has a dimension of 508 µm × 620 µm with a height of 500 µm. The substrate used is GaAs material. The relative permittivity of the substrate is 12.9. This proposed MEMS switch is designed and simulated in both UP (ON) state and DOWN (OFF) state. The proposed RF-MEMS switch is designed and simulated using Ansoft High frequency structure simulator (HFSS) electromagnetic simulator. The simulated result shows better performance parameters such as return loss ( <-10 dB)  and insertion loss ( > -0.5 dB) in UP state, whereas return loss ( > -0.5 dB) and isolation (<-10 dB) in DOWN state. This switch has good isolation characteristics of – 43 dB at 27 GHz frequency.
Volume: 15
Issue: 2
Page: 971-978
Publish at: 2019-08-01

Constructing population of initial university timetable: design and analysis

10.11591/ijeecs.v15.i2.pp1109-1118
Juliana Wahid , Syariza Abdul-Rahman , Aniza Mohamed Din , Naimah Mohd-Hussin
The construction of population of initial timetable is an essential stage in population-based metaheuristic approach for solving curriculum-based university course timetabling problem because it may impact the quality of the final timetable. This paper presents population of initial timetable construction approach in curriculum based course timetabling problem by using the graph heuristics to determine the sequential order of courses/lectures to be assigned in the timetable. The graph heuristics were implemented as single and combination of two heuristics. The courses in curriculum-based university course timetabling problem that was organized based on the heuristics setting will be repeatedly assigned to valid empty slots while fulfilling all the hard constraints. If a course is unable to be assigned to whichever slots because of no more valid empty slots, it will be inserted into the unscheduled courses/lectures list. The unscheduled courses/lectures list will be assigned later to the timetable using several procedures executed in a sequence. The approaches were tested on the ITC2007 instances and the results were analyzed with some statistical tests to determine the best setting of heuristics in the construction approach.  The result shows that the construction approach with combination of largest degree followed by saturation degree heuristic, generate the maximum number of population of initial timetables. The result from this study can be used in the improvement stage of metaheuristic algorithm that uses population-based approach.
Volume: 15
Issue: 2
Page: 1109-1118
Publish at: 2019-08-01
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