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29,939 Article Results

A method to convert non-numeric characters into numerical values in dynamic time warping for string matching

10.11591/ijece.v11i3.pp2660-2665
Hyun Jun Park
Dynamic time warping (DTW) is one of the well-known algorithms for measuring similarity between two temporal sequences, and it can be used for character matching. It uses a distance of two character strings. However, since the characters are non-numeric, it must be assigned to numerical values to calculate a distance between two character strings. Therefore, in this paper, we propose a method to convert non-numeric characters into numerical values in dynamic time warping for string matching. The proposed method uses normalized correlation coefficient, and it makes DTW gives more accurate results. Experimental results show that the proposed method gives excellent results.
Volume: 11
Issue: 3
Page: 2660-2665
Publish at: 2021-06-01

Design of a high performance AC-DC LED driver based on SEPIC topology

10.11591/ijpeds.v12.i2.pp870-885
Fouzia Ferdous , A. B. M. Harun ur Rashid
Light emitting diodes (LEDs) are current driven devices. So, it is essential to maintain the stability of LED voltage and current. Variation of temperature may cause of instabilities and bifurcations in the LED driver. Driving LEDs from an offline power source faces design challenges like it have to maintain low harmonics in input current, to achieve high power factor, high efficiency and to maintain constant LED current and to ensure long lifetime. This paper proposes the technique of harmonics reduction by using parametric optimization of Single ended primary inductor converter (SEPIC) based LED driver. Without optimization of SEPIC parameters input energy will not be properly transferred to the load and this un-transferred energy will be transmitted to the source. Consequently, the quality of input current will be hampered i.e. harmonics will contaminate the input current. Focussing this, the paper has presented the design of a non-isolated integrated-stage single-switch constant current LED driver operating in discontinuous conduction mode (DCM) in SEPIC incorporating the design of control circuit with soft start mechanism. This LED driver has achieved a good efficiency (90.6%) and high-power factor (0.98) with reduced harmonics (3.35%). System stability has been determined and simulation studies are performed to confirm the validity of the LED driver circuit. A laboratory prototype is built.
Volume: 12
Issue: 2
Page: 870-885
Publish at: 2021-06-01

On human body transmission wearable diamond dipole antennas above engineered jackets

10.11591/ijeecs.v22.i3.pp1513-1519
Muhammad Azfar bin Abdullah , Mohamad Kamal A. Rahim , Noor Asmawati Samsuri , Mohd Fairus , Mohd Khairul Hisham Ismail , Huda A. Majid
This paper presents the propagation of dual-band diamond dipole antenna on three various jackets. The jackets are purely fleece fabric with Shieldit fabric patches on top of it. The network analyzers with the flexible lossless coaxial cable are used to measure the communication of the antennas. The experiment involves a man with ideal body mass index (BMI) wearing the jackets by placing the flexible antennas on top of it. It is observed that the best on-body communication is by wearing the engineered jacket. The 10 dB improvements are observed when the antenna is positioned on top of engineered jacket contrast to the regular jacket. In other words, the performance of the antenna is also be determined by antenna placement. High transmission lossesses cause the antenna mismatch when the antennas are positioned above the full conductive jacket.
Volume: 22
Issue: 3
Page: 1513-1519
Publish at: 2021-06-01

Investigating communicative barriers on construction industry productivity in Malaysia: An overview

10.11591/ijere.v10i2.21163
Khairul Firdaus Ne'Matullah , Lim Seong Pek , Siti Aisyah Roslan
The evolution of technology has changed the way how human communicate in the current time. With the advancement of technology, instructions and messages could be delivered in a split second. Even though life is made easy with technology, some information and details should be delivered face-to-face in order to avoid communication breakdown. This study was carried out to determine the language needs by foreign workers working at construction sectors in Malaysia. The study created an overview on how communication affects productivity in completing tasks on time. The results from this study lead to a development of language modules for foreign workers training. An online survey was carried out through social media on construction site supervisors around Malaysia in getting their feedback related to the origin of their co-workers and the importance of English language as medium of instruction for task fulfilment. Results indicated that language barriers had affected productivity in the sector of construction in Malaysia. Besides, results also noted that cross-cultural differences had put foreign workers at risk and caused wastage to time and manpower.
Volume: 10
Issue: 2
Page: 476-482
Publish at: 2021-06-01

Acoustic study of the influence of climate change on the propagation of noise generated by industrial units in real-time: by an industrial zone in Algeria

10.11591/ijpeds.v12.i2.pp1275-1282
Arbaoui Iliace , Tadjeddine Ali Abderrazak , Hamiani Hichem , Hamou Ahmed
The industrial revolution in the field of gas and oil treatment that has known the Oran region-Algeria-has participated in the production and propagation of noise pollution and loud noises on the environment and around the places residential, for this, a multitude of noises are now part of our daily life. This contribution concerns the propagation of noise pollution in the industrial environment and the effects caused by atmospheric pollution which has a great influence on the phenomenon of planetary climate change and on meteorological parameters, the latter having a great influence on the propagation of noise. Our study is part of the objective of evaluating the noise levels emitted by gas installations in the industrial zone of ArzewOran, and of seeing the effects of the variation of meteorological parameters on the propagation of noise. To do this, we have adopted a precise in-situ methodology. Subsequently, for the processing of the measurement results, we opted for the COD-TYMPAN software in real-time as a calculation tool to interpret our results
Volume: 12
Issue: 2
Page: 1275-1282
Publish at: 2021-06-01

Protecting Android based applications from malware affected through SMS messages

10.11591/ijeecs.v22.i3.pp1580-1589
J. Sasi Bhanu , J. K. R. Sastry , T. Chandrasekhara Reddy
Users use Android-based applications for communicating through emailing, text messaging, and transmission of audio and video objects. The attackers manipulate the email, text, videos, or audio so that users' receipt of the messages causes malware through their handheld devices. A runtime routine is invoked, which causes damage to the local resources of the mobile phone. The manipulation of the messages is done using different signatures, making it difficult to recognize the same using a single approach. Multiple approaches are sometimes required to detect different signature-based incoming messages. Choosing a method that suits the signature of the incoming message is the key. Malware can also enter at the time of installing third-party apps, clicking on the links provided in the messages, installing and invoking the malware in the background. Many issues are involved in dealing with malware detecting, prevention, and curing. A comprehensive architecture is required to deal with every aspect of dealing malware. In this paper, a comprehensive architecture is presented that considers malware's issue, especially concerning malware affected through short message service (SMS) messages operated under the Android operating system. The disection of the SMS messages have been implemented and 99% accuracy has been achieved.
Volume: 22
Issue: 3
Page: 1580-1589
Publish at: 2021-06-01

Gifted education: Perspectives and practices of school principals in Bahrain

10.11591/ijere.v10i2.21176
Osama Al-Mahdi , Abduyah Binte Yaakub , Abdelbaky Abouzeid
Research on giftedness and gifted education has a rich history. Researchers have consistently pointed to the educational leadership perspectives on giftedness, and inequitable identification of policies and practices in gifted education. Research suggests there is a widening gap in the level of comprehensive knowledge in gifted education that is critical for school improvement. This paper examined school principals’ (n=29) perceptions regarding giftedness among Bahraini students. The study focuses on exploring the characteristics school principals attribute to giftedness in their schools, the methods employed by schools to identify gifted students from the school principals' perspectives, and the educational provisions school principals used to support gifted students in their school. The study also searches for any significant differences among school principals in their views on these three dimensions. The study employed quantitative methodology and the analysis of the research questionnaire included descriptive and interpretive analysis (ANOVA and T-test). The findings indicate that the school principals looked at giftedness mainly from an academic and school perspective. The results indicate some dissonance between what the principals’ perceptions on giftedness are and the educational support that they provided to the gifted students in their schools.
Volume: 10
Issue: 2
Page: 576-587
Publish at: 2021-06-01

Variable reluctance synchronous machines in saturated mode

10.11591/ijpeds.v12.i2.pp662-673
Hleli Hanene , Flah Aymen , Tounsi Souhir
Electric vehicle seems largely based on electrical machines. Finding the best motor type seems be important for having more performances and a transport system robustness. In this work, we present an analytical model of the synchronous machine with variable reluctances in linear and saturated modes. The angular position of the rotor (θ) and the phase current (i) will beused as parameters. The analytical model of this machine will allow us to determinate its magnetic characteristics such inductors, magnetic flux and electromagnetic torque. The results obtained by the analytical model are compared with those obtained by the finite element method. So, basing on Matlab/Simulink tool and by working with finite element method, these results are depicted and the paper objective is illustrated.
Volume: 12
Issue: 2
Page: 662-673
Publish at: 2021-06-01

Keeping millennials from quitting due to work stress: The roles of mattering, commitment and entrepreneurship orientation

10.11591/ijphs.v10i2.20839
Kususanto Ditto Prihadi , Calvin K.W. Chang , Lyann Goo
Studies in pre-pandemic era had established that millennial workers tend to leave their job due to low organizational commitment or strong entrepreneurial orientation; however, the pandemic had brought down economy due to lockdowns, work stress and mental health instability, limitation of business hours, working from home policy, downsizing of companies, and many other changes. This situation might contribute to a novel situation among millennial employees and their turnover intention might be developed differently. Because mattering has protective feature against work stress and depression, we hypothesized that their it will negatively contribute to their turnover intention, and this contribution is mediated by the organizational commitment. Furthermore, we also hypothesized that this phenomenon would only occur in the condition of lower levels of entrepreneurial orientation. Data was collected from 354 purposively recruited millennial employees who responded to the scales of mattering, organizational commitment, entrepreneurial orientation and turnover intention through online surveys Analyses were conducted with Bootstrap Method in PROCESS Macro Model 10. The findings indicated that the moderated mediation occurred; organizational commitment fully mediated the link between mattering and turnover intention among participants with moderate and high levels of entrepreneurial orientation.
Volume: 10
Issue: 2
Page: 445-450
Publish at: 2021-06-01

A regenerative braking energy recuperation from elevator operation in building by active rectifier

10.11591/ijpeds.v12.i2.pp811-821
An Thi Hoai Thu Anh , Luong Huynh Duc
Elevators- means of vertical transportation to carry people and goods are an indispensable part in offices, high-rise buildings, hospitals, commercial areas, hotels, car-parks when blooming urbanization develops worldwide. However, the level of energy consumption in elevator operation is significant, so energy saving solutions have been outlined and applied in practice. With frequent braking phases, regenerative braking energy is wasted on braking resistors. Therefore, this paper proposes regenerative braking energy recuperation method for elevator operation in building by active rectifiers enabling the braking energy to be fed back into utility grid. Simulation results conducted by MATLAB with data collected from OCT5B building-RESCO new urban area, Ha noi, Vietnam have verified saving energy of using active rectifiers replacing diode rectifiers up to 33%.
Volume: 12
Issue: 2
Page: 811-821
Publish at: 2021-06-01

Partial discharges location in power transformers using piezoceramic sensors

10.11591/ijece.v11i3.pp1942-1950
B. Danouj , S. A. Tahan , E. David , M. Lotfi
The detection and the spatial localization of partial discharges in high-voltage electrical machines are considered as an effective method in predictive maintenance that can provide valuable information on the health of the insulation system and allow to determine accurately the location of the risky insulation elements, which in turn will avoid any premature equipment’s deterioration by scheduling preventive maintenance action. After confirming in a previous published paper the efficiency of a new generation of piezoceramics sensors (high temperature ultrasonic transducers) to detect and characterize partial discharges, we are going to investigate, in this work, a second potential of this technology to locate the partial discharge sources by relying on its ability to detect acoustic signals emitted by partial discharge sources. We will present experimental results, demonstrating the effectiveness of these sensors to locate partial discharges sources and, we will also present an algorithm for calculating the partial discharge foci, based on the acoustic wave flight time.
Volume: 11
Issue: 3
Page: 1942-1950
Publish at: 2021-06-01

Comparison between butterfly optimization algorithm and particle swarm optimization for tuning cascade PID control system of PMDC motor

10.11591/ijpeds.v12.i2.pp736-744
Kareem G. Abdulhussein , Naseer M. Yasin , Ihsan J. Hasan
In this paper, two optimization methods are used to adjust the gain values for the cascade PID controller. These algorithms are the butterfly optimization algorithm (BOA), which is a modern method based on tracking the movement of butterflies to the scent of a fragrance to reach the best position and the second method is particle swarm optimization (PSO). The PID controllers in this system are used to control the position, velocity, and current of a permanent magnet DC motor (PMDC) with an accurate tracking trajectory to reach the desired position. The simulation results using the Matlab environment showed that the butterfly optimization algorithm is better than the particle swarming optimization (PSO) in terms of performance and overshoot or any deviation in tracking the path to reach the desired position. While an overshoot of 2.557% was observed when using the PSO algorithm, and a position deviation of 7.82 degrees was observed from the reference position.
Volume: 12
Issue: 2
Page: 736-744
Publish at: 2021-06-01

Optimization of double stator PMSM with different slot number in inner and outer stators using genetic algorithm

10.11591/ijpeds.v12.i2.pp726-735
Mohd Saufi Ahmad , Dahaman Ishak , Tiang Tow Leong , Mohd Rezal Mohamed
This paper describes the performance enhancement of double stator permanent magnet synchronous machines (DS-PMSM) based on genetic algorithm optimization (GAO). Generally, throughout the development stage, an analytical calculation is implemented to build the initial model of the DS-PMSM since the analytical calculation can provide the initial parameters based on the types and materials used in the machine design. For further improvement, GAO might potentially be applied to provide the optimization technique in searching the optimal motor parameters iteratively and intelligently with specific objective functions. For this aim, a three-phase, DS-PMSM with different number of slots between the outer and inner stators is first designed by using analytical parameter estimation and then later optimized by GAO. The outer and inner stators have 12-slots and 9-slots respectively, while, the rotor carries 10 magnetic poles. Four main input motor parameters, i.e. outer stator slot opening, outer magnet pole arc, inner stator slot opening and inner magnet pole arc are varied and optimized to achieve the design objective functions, i.e. high output torque, low torque ripple, low cogging torque and low total harmonic distortion (THDv). The results from the optimized GAO are compared with the initial motor model and further validated by finite element method (FEM). The results show a good agreement between GAO and FEM. GAO has achieved very significant improvements in enhancing the machine performance.
Volume: 12
Issue: 2
Page: 726-735
Publish at: 2021-06-01

Developing an automatic brachial artery segmentation and bloodstream analysis tool using possibilistic C-means clustering from color doppler ultrasound images

10.11591/ijece.v11i3.pp2653-2659
Joonsung Park , Doo Heon Song , Kwang Baek Kim
Automatic segmentation of brachial artery and blood-flow dynamics are important for early detection of cardiovascular disease and other vascular endothelial malfunctions. In this paper, we propose a software that is noise tolerant and fully automatic in segmentation of brachial artery from color Doppler ultrasound images. Possibilistic C-Means clustering algorithm is applied to make the automatic segmentation. We use HSV color model to enhance the contrast of bloodstream area in the input image. Our software also provides index of hemoglobin distribution with respect to the blood flow velocity for pathologists to proceed further analysis. In experiment, the proposed method successfully extracts the target area in 59 out of 60 cases (98.3%) with field expert’s verification.
Volume: 11
Issue: 3
Page: 2653-2659
Publish at: 2021-06-01

Application of PSO for optimal coordination of directional over-current relays in distribution system with distributed renewable energy sources

10.11591/ijaas.v10.i2.pp188-192
Lazhar Bougouffa , Abdelaziz Chaghi
The use of distributed renewable energy sources (D-RES) in the electrical network has expanded greatly. However, integration of these resources into distribution systems caused more problems in protection related issues such as mis-coordination and changes the direction and value of fault currents. When connecting new D-RES to electrical power distribution networks, it is required to re-coordinate directional over-current relays (DOCR) to ensure the continuity of the power transmission when the short circuits take place. This work presented a particle swarm optimization (PSO) algorithm to determine two independent variables called pickup current (Ip) and time dial setting (TDS) for optimal setting of relays. From analysis result, the impacts of RES location in the distribution system on DOCRs had been observed on the optimal relays settings.
Volume: 10
Issue: 2
Page: 188-192
Publish at: 2021-06-01
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