Articles

Access the latest knowledge in applied science, electrical engineering, computer science and information technology, education, and health.

Filter Icon

Filters article

Years

FAQ Arrow
0
0

Source Title

FAQ Arrow

Authors

FAQ Arrow

27,762 Article Results

Item Response Theory: An Introduction to Latent Trait Models to Test and Item Development

10.11591/ijere.v7i2.12900
Ado Abdu Bichi , Rohaya Talib
Testing in educational system perform a number of functions, the results from a test can be used to make a number of decisions in education. It is therefore well accepted in the education literature that, testing is an important element of education. To effectively utilize the tests in educational policies and quality assurance its validity and reliability estimates are necessary. There are two generally acceptable frameworks used in evaluating the quality of test in educational and psychological measurements, these are; Classical Test Theory (CTT) and Item Response Theory (IRT). The estimates of test items validity and reliability depend on a particular measurement model used. It is vital for a test developer to be familiar with the different test development and item analysis methods in order to facilitate the development of a new test. The CTT is a traditional approach which was widely criticise in the measurement community for its shortcomings such as sample dependency of coefficient measures and estimates of measurement error. However, the IRT is a modern approach which provides solutions to most of the CTT’s identified shortcomings. This paper therefore, provides a comprehensive overview of the IRT and its procedures as applied to test item development and analysis. The paper concludes with some suggestions for test developers and test specialists at all levels to adopt IRT for its identified crucial theoretical and empirical gains over CTT. IRT based parameter estimates should be superior and reliable than CTT based parameter estimates. With these features, IRT can help resolve the problems associated with test design based on CTT.
Volume: 7
Issue: 2
Page: 142–151
Publish at: 2018-06-01

Speech Input as an Alternative Mode to Perform Multi-touch Gestures

10.12928/telkomnika.v16i3.8417
Nor Hidayah; Universiti Kebangsaan Malaysia Hussain , Tengku Siti Meriam; Universiti Kebangsaan Malaysia Tengku Wook , Siti Fadzilah; Universiti Kebangsaan Malaysia Mat Noor , Hazura; Universiti Kebangsaan Malaysia Mohamed
Speech is fundamental and the most dominant form of communication. Speech input may facilitate natural interaction between humans and computers. For children, this input mode supports their interaction with application systems. This study addresses speech input as an alternative mode in order to improve multi-touch gesture interactions. Previous studies show that children difficult to perform multi-touch gestures successfully. In fact, multi-touch is parts of basic core gestures that have been adapted to most of the learning applications. This study uses the Wizard-of-Oz method and posts interview, involving nine preschool children between ages of four to six years old. Results of the study show children’s interactional ability using speech input towards systems and positive feedback received from them regarding the prototype of the systems. The findings from this study highlight the opportunities and challenges in using speech input to increase the success of children’s interaction with multi-touch gestures.
Volume: 16
Issue: 3
Page: 1367-1375
Publish at: 2018-06-01

Review: Dual Band Microstrip Antennas for Wireless Applications

10.11591/ijaas.v7.i2.pp143-151
Rakesh Kumar Bajpai , Rajeev Paulus , Ashish Singh , Mohammad Aneesh
In this manuscript, a review of dual band microstrip antennas for wireless communication is presented. This review manuscript discusses regarding the geometric structures, different methods of analysis for antenna characteristics, and different types of wireless applications.
Volume: 7
Issue: 2
Page: 143-151
Publish at: 2018-06-01

Effect of the Thickness of High Tc Superconducting Rectangular Microstrip Patch over Ground Plane with Rectangular Aperture

10.11591/ijece.v8i3.pp1611-1617
Nabil Boukhennoufa , Lotfi Djouane , Houcine Oudira , Mounir Amir , Tarek Fortaki
In recent years, a great interest has been observed in the development and use of new materials in microwave technology. Particularly, a special interest has been observed in the use of superconducting materials in microwave integrated circuits, this is due to their main characteristics. In this paper, the complex resonant frequency problem of a superconductor patch over Ground Plane with Rectangular Aperture is formulated in terms of an integral equation, the kernel of which is the dyadic Green’s function. Galerkin’s procedure is used in the resolution of the electric field integral equation. The surface impedance of the superconductor film is modeled using the two fluids model of Gorter and Casimir. Numerical results concerning the effect of the thickness of the superconductor patch on the characteristics of the antenna are presented.
Volume: 8
Issue: 3
Page: 1611-1617
Publish at: 2018-06-01

Lowpass Filter with Hilbert Curve Ring and Sierpinski Carpet DGS

10.12928/telkomnika.v16i3.7722
Dian Widi; Universitas Mercu Buana Astuti , Intan; Universitas Mercu Buana Wahyuni , Muslim; Universitas Mercu Buana Muslim , Mudrik; Universitas Mercu Buana Alaydrus
Good performance and compact size are the paramaters which are vital when desiging a filter. One of the creteria of good performance is selectivity. This research, conducted by Hilbert Curve Ring and Siepinski Carpet, is used as defected ground structure to overcome filter selectivity. By using three cascadeds Hilbert Curve Ring defected ground structure cells and three steps Sierpinski carpet, a lowpass filter is designed and fabricated. The measurement result for lowpass filterwith Hilbert Curve Ring defected ground structure has sharper selectivity with the cut off frequency at 2.173 GHz and the insertion loss value is 2.135 dB. While the measurement result for three steps Sierpinski carpet has the cut off frequency at 1.728 GHz and the insertion loss value is 0.682 dB.
Volume: 16
Issue: 3
Page: 1092-1100
Publish at: 2018-06-01

Integrative Model for Quantitative Evaluation of Selection Telecommunication Tower Site

10.12928/telkomnika.v16i3.8922
Janah A.; Girne American University Asassfeh , Mokhled; Mutah University AlTarawneh , Fadiya; Girne American University Samson
This paper analyzes the weight of impact factors on selection the antenna places for mobile telecommunication system in Jordan. The new technique plays a lead role in divided area and selects the place of antennas' sites. The main objective of this research is to minimize the antenna numbers in order to reduce the cost. Research follows flowcharting categories and stages as: The first stage aim to classify the effective factors on the: signal radius, better position of antenna from candidate points, reserved area, and non-preferring position. The second stage focuses on finding the effective weight of these factors on the decision. The third stage suggest the new proposed approach by implement the MCLP and P-center problems in linear function. The last stage has the pseudo code for the proposed approach, where the proposed approach provides the solution that helps the planners in telecommunication industry and in related government agencies make informed position of the antennas.
Volume: 16
Issue: 3
Page: 1158-1164
Publish at: 2018-06-01

Autonomous Traffic Signal Control using Decision Tree

10.11591/ijece.v8i3.pp1522-1529
Rithesh R N , Vignesh R. , Anala M. R.
The objective of this paper is to introduce an effective and efficient way of traffic signal light control to optimize the traffic signal duration across each lanes and thereby, to minimize or completely eliminate traffic congestion. This paper introduces a new approach to resolve the traffic congestion problem at junctions by making use of decision trees. The vehicle count in the real time traffic video is determined by Image Processing technique. This information is fed to the decision tree based on which the decision is made regarding the status of traffic signal lights of each lane at the junction at any given instant of time.
Volume: 8
Issue: 3
Page: 1522-1529
Publish at: 2018-06-01

AC-AC Voltage Controller of Power Supply for Heater on Drying System

10.12928/telkomnika.v16i3.5194
Renny; Politeknik Elektronika Negeri Surabaya Rakhmawati , Farid Dwi; Politeknik Elektronika Negeri Surabaya Murdianto
The coconut fruits is very useful to be processed into cooking oil and it can meet the needs of cooking for Indonesia people, But before the coconuts processed into oil, The coconuts should be dried first. Usually the drying process is manually, that is dried in the sun. Unfortunately this way is not hygienic and can’t be done continuously, causing the coconut fungus overgrow. This paper proposes methode to solve the problem above.This research makes the dryer coconut fruitssystem by using the heater.Dryer system used for dry some coconut fruits that must be reduced the water content up to 5%, this dry coconutis called copra. System requires heater which will be regulated the temperature. Heater temperature setting is done by adjusting the heater supply voltage, and this is the task of ac to ac voltage controller. Ac to ac voltage controller is a circuit converter is capable converting ac voltage with value 220 Vrms at 50 Hz frequency and have waveform pure sinusoidal become ac voltage frequency at 50 Hz with an output voltage suitable with our need but the voltage waveform not impure sinusoidal or defective as a result firing angle effects. The output voltage which we set determines the value of the heater temperature. The output voltage is set from the firing angle of the triac component using the addition and decreasing angle values. Based on the results of experiments that have been done, if the drying chamber which has volume 135.2 liters and the temperature regulated at 700 C then the heater with a power requirement of 400 W should receive supply 216 V from ac to ac voltage controller. So the triac of ac to ac voltage controller fired on 0.55 radians so that the to ac voltage controller that gets 220 V input voltage can produce 216 V output voltage.
Volume: 16
Issue: 3
Page: 1061-1070
Publish at: 2018-06-01

Interference Temperature Measurements and Spectrum Occupancy Evaluation in the Context of Cognitive Radio

10.11591/ijeecs.v10.i3.pp1007-1012
Paulson N. Eberechukwu , Dauda S. Umar , Alias Mohd , Kamaludin M. Y. , M. Adib bin Sarijari , Rozeha A. Rashid
This paper presents a refined radio spectrum measurement platform specifically designed for spectrum occupancy surveys in the context of Cognitive radio. Cognitive radio permits the opportunistic usage of licensed bands by unlicensed users without causing harmful interference to the licensed user. In this work, a study based on the measurement of the 800 MHz to 2.4 GHz frequency band at two different locations inside Universiti Teknologi Malaysia (UTM), Johor Bahru campus, Malaysia is presented. Two Tektronix RSA306B spectrum analyzer are set up to conduct simultaneous measurements at different locations for a 24 hours period. The analysis conducted in this work is based on the real spectrum data acquired from environment in the experimental set up. Busy and idle channels were identified. The channels subject to adjacent-channel interference were also identified, and the impact of the detection threshold used to detect channel activities was also discussed. The consistency of the observed channel occupation over a range of thresholds and a sudden drop has good characteristics in determining an appropriate threshold needed in order to avoid interference.
Volume: 10
Issue: 3
Page: 1007-1012
Publish at: 2018-06-01

A New Chaotic Map for Secure Transmission

10.12928/telkomnika.v16i3.8545
Hamsa A.; Nahrain University Abdullah , Hikmat N.; Nahrain University Abdullah
The secure communication through synchronization between two identic chaotic systems have recently gained a lot of interest. To implement a robust secure system based on synchronization, there is always a need to generate new discrete dynamical systems and investigate their performances in terms of amount of randomness they have and the ability to achieve synchronization smoothly. In this work, a new chaotic system, named Nahrain, is proposed and tested for the possible use in secure transmission via chaos synchronization as well as in cryptography applications. The performance of the proposed chaotic system is tested using 0-1 test, while NIST suite tests are used to check the randomness statistical properties. The nonlinear control laws are used to verify the synchronization of master-slave parts of the proposed system. The simulation results show that Nahrain system has chaotic behavior and synchronizable, while the equivalent binary sequence of the system has excellent randomness statistical properties. The numerical results obtained using MATLAB for 0-1 test was 0.9864, and for frequency test was 0.4202, while for frequency test within a block was 0.4311. As a result, the new proposed system can be used to develop efficient encryption and synchronization algorithms for multimedia secure transmission applications.
Volume: 16
Issue: 3
Page: 1135-1142
Publish at: 2018-06-01

On the High Dimentional Information Processing in Quaternionic Domain and its Applications

10.11591/ijaas.v7.i2.pp177-190
Sushil Kumar , Bipin Kumar Tripathi
There are various high dimensional engineering and scientific applications in communication, control, robotics, computer vision, biometrics, etc.; where researchers are facing problem to design an intelligent and robust neural system which can process higher dimensional information efficiently. The conventional real-valued neural networks are tried to solve the problem associated with high dimensional parameters, but the required network structure possesses high complexity and are very time consuming and weak to noise. These networks are also not able to learn magnitude and phase values simultaneously in space.  The quaternion is the number, which possesses the magnitude in all four directions and phase information is embedded within it. This paper presents a well generalized learning machine with a quaternionic domain neural network that can finely process magnitude and phase information of high dimension data without any hassle. The learning and generalization capability of the proposed learning machine is presented through a wide spectrum of simulations which demonstrate the significance of the work.
Volume: 7
Issue: 2
Page: 177-190
Publish at: 2018-06-01

Optimization of Parallel K-means for Java Paddy Mapping Using Time-series Satelite Imagery

10.12928/telkomnika.v16i3.6876
Alvin; Bogor Agricultural University Fatikhunnada , Kudang Boro; Bogor Agricultural University Seminar , Liyantono; Bogor Agricultural University Liyantono , Mohamad; Bogor Agricultural University Solahudin , Agus; Bogor Agricultural University Buono
Spatiotemporal analysis of MODIS Vegetation Index Imagery widely used for vegetation seasonal mapping both on forest and agricultural site. In order to provide a long-terms of vegetation characteristic maps, a wide time-series images analysis is needed which require high-performance computer and also consumes a lot of energy resources. Meanwhile, for agriculture monitoring purpose in Indonesia, that analysis has to be employed gradually and endlessly to provide the latest condition of paddy field vegetation information. This research is aimed to develop a method to produce the optimized solution in classifying vegetation of paddy fields that diverse both spatial and temporal characteristics. The time-series EVI data from MODIS have been filtered using wavelet transform to reduce noise that caused by cloud. Sequential K-means and Parallel K-means unsupervised classification method were used in both CPU and GPU to find the efficient and the robust result. The developed method has been tested and implemented using the sample case of paddy fields in Java Island. The best system which can accommodate of the extend-ability, affordability, redundancy, energy-saving, maintainability indicators are ARM-based processor (Raspberry Pi), with the highest speed up of 8 and the efficiency of 60%.
Volume: 16
Issue: 3
Page: 1409-1415
Publish at: 2018-06-01

Security of a New Cryptographic Hash Function - Titanium

10.11591/ijeecs.v10.i3.pp1244-1250
Abdullah Nazeeh Saleh , Mohammad A. Al-Ahmad
This paper introduces the security analysis of Titanium hash function that uses SF block cipher and follows sponge construction. A brief description of the sponge function and the design choice of Titanium are introduced. Basic security criteria of random function have been presented and studied on Titanium and then, differential cryptanalysis on Titanium has been performed and showed the resistance of it on the most recent differential attacks. A table of security discussions finalizes the paper and describes the complexity of Titanium on brute force cryptanalysis.
Volume: 10
Issue: 3
Page: 1244-1250
Publish at: 2018-06-01

Investigating the Intelligent Methods of Loss Minimization in Induction Motors

10.12928/telkomnika.v16i3.8293
Sadegh; Islamic Azad University Hesari , Mohsen; Islamic Azad University Noruziazghandi , Ali Asghar; Islamic Azad University Shojaei , Mehdi; sfarayen University of Technology Neyestani
Induction motors are widely used in industry. Given the increasing demand for electric machines in different industries, optimization of these machines to achieve a high efficiency with low cost is of utmost importance. Loss-minimization in motor is done in three ways: 1) optimizing motor selection and design; 2) improving motor power supply waveforms; and 3) using appropriate controlling methods in drives. Often, inductive motors provide the maximum efficiency in their nominal load. In most applications it is necessary for a motor to work in light loads for a long time, e.g. in conveyors, elevators, etc. In these conditions, the machine load is not the nominal load, and a higher percentage of the input power is lost. So, in the case of variable load, the first and second methods cannot increase the efficiency; but the third method provides a large flexibility in decreasing motor losses. In this paper, the application of the third method in loss-minimization is reviewed. These motor losses are mostly related to the controlling strategy and basically occur in light-load conditions. There are various strategies to decrease this kind of losses, which are generally divided into two categories: classic methods and intelligent methods. In this paper, first the classic methods, including losses model control (LMC), flux control as a function of torque and search control (SC), are discussed. Then the intelligent methods, such as genetic algorithm, PSO, fuzzy logic and artificial neural network are investigated. This paper is presented while the last methods of efficiency improvement are being investigated and each method is described briefly.
Volume: 16
Issue: 3
Page: 1034-1053
Publish at: 2018-06-01

Harmonic Impact in Induction Generator Voltage Using Thyristor Control Reactor

10.12928/telkomnika.v16i3.7788
Suprihardi; Politeknik Negeri Lhokseumawe Suprihardi , Yaman; Politeknik Negeri Lhokseumawe Yaman , Zamzami; Politeknik Negeri Lhokseumawe Zamzami , Nelly; Politeknik Negeri Lhokseumawe Safitri
As commonly known that theload fluctuations that have been performed on an induction motor operated as an induction generator (IG) triggers unstable induced voltage and frequency. Asthe result, the load that receiving the power quality is not running properly and the efficiency is low. The problems that have beenmitigated in this research in such way is the stability of the voltage that generated by IG due to fluctuating loading, and the harmonics can be damped by single tuned due to the work of thyristors and non-linear loads. The used method is the Ziegler-Nichols method by measuring and testing the design of prototype to get the best performance in stabilizing the voltage by using thyristor control reactor (TCR). The results showed that the induced generator with single tuned filter and TCR to nonlinear load variation at 1618 RPM is maintained stably for the voltage and frequency. Although, 3rd order harmonics of voltage and current that has been tuned can be dampedby using THDI 8.36%. Furthermore, it can be said that the response that generated by voltage control system using proportionalintegral (PI) control in 1kW-4 poles three-phase IG with additional and reductionalload generated a stable response.
Volume: 16
Issue: 3
Page: 1054-1060
Publish at: 2018-06-01
Show 1306 of 1851

Discover Our Library

Embark on a journey through our expansive collection of articles and let curiosity lead your path to innovation.

Explore Now
Library 3D Ilustration