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27,404 Article Results

The Analysis of Student Colla borative Work Inside Social Learning Network Analysis Based on Degree and Eigenvector Centrality

10.11591/ijece.v6i5.pp2488-2498
Andi Besse Firdausiah Mansur , Norazah Yusof , Ahmad Hoirul Basori
Social learning network analysis is a potential approach to analyze the behaviour of students in collaborative work. However, most of the previous works focus on asynchronous discussion forum as the learning activity.  Very few of them are trying to analyze the students' collaborative work while using wiki e-learning. This paper proposes the degree centrality and eigenvector method for identifying the collaborative work of students while in wiki e-learning. The log data of the Moodle e-learning system is observed that records the students' activities and actions while using wiki.  The result shows that there is a close similarity between the degree centrality and the eigenvector. The result also reveals the students who obtain high outdegree values.  Furthermore, Agent_1 and Agent_12 represent the students who obtained high outdegree values, which mean these two nodes are acting as source providers that able to supply information and knowledge through the network. This result also strengthened by value of closeness and betweenness where Agent_1 and Agent_12 leading on this measurement. The high closeness value of Agent_1 and Agent_12 will lead into fast spreading information since they have fastest route and has the most direct route to the other node inside the network, thus collaborative work is easy to be initialized by these Agents. This work has successfully identified collaborative work of student. This finding is believed to bring enormous benefit on the e-learning system improvement in the future.
Volume: 6
Issue: 5
Page: 2488-2498
Publish at: 2016-10-01

An Energy-Efficient Key Management Scheme using Trust Model for Wireless Sensor Network

10.11591/ijeecs.v4.i1.pp141-147
P. Raja , E. Karthikeyan
In wireless sensor networks (WSNs), secret shared keys must be established with the neighboring nodes in order to achieve secure communication. The challenge issues for secured communication in WSN are the Key management. Location Dependent Key (LDK) management is a suitable scheme when compared to other location based key management schemes because of lesser memory space requirement and lesser number of keys to be stored on each sensor node. However, the LDK is affected by communication interference problem which is solved by the key is distributed based on trust model. The distributed key updates and revocation processes are effectively resist inside attackers. An energy-efficient Key Management with Trust Model (KM-TM) for WSNs is proposed to achieve the secured communication and the nodes are resisting from the attackers. The performances of proposed KM-TM for WSNs are evaluated in terms of trustworthiness of sensor nodes and security breaches more effectively.  
Volume: 4
Issue: 1
Page: 141-147
Publish at: 2016-10-01

Estimation of Optimum Tilt Angle of PV Panel for Maximum Energy Harvesting

10.11591/ijece.v6i5.pp2015-2024
K. Parkavi Kathirvelu , B. Viswanathan
In solar energy conversion system harvesting of maximum energy is necessary in order to maximize the utilization of available energy. The maximum energy from the solar panel can be extracted by keeping solar panel in an optimum tilt angle. Various approaches are available to find optimum tilt condition of the solar panel.  In this work two different positions of the panel such as fixed tilt, seasonal tilt were analyzed using isotropic and anisotropic models. Among the various models available in the above said broad category six models such as Liu-Jordan, Koronokis Model, Badescu model, Hay and Davis model, Reindel model,  Hay&Davis and Reindel & Klucher combined model are incorperated to predict the  monthly average of daily global solar irradiation of the inclined panels held in SASTRA University, Thanjavur (India) location. Statistical tests have been performed in order to evaluate the consequences predicted by the models with the experimental results. Finally a detailed comparison between fixed tilt and seasonal tilt of the panel has been carried out and the suitable model for this location is also suggested.
Volume: 6
Issue: 5
Page: 2015-2024
Publish at: 2016-10-01

Improved Canny Edges Using Cellular Based Particle Swarm Optimization Technique for Tamil Sign Digital Images

10.11591/ijece.v6i5.pp2158-2166
M Krishnaveni , P Subashini , TT Dhivyaprabha
The development of computer based sign language recognition system, for enabling communication with hearing impaired people, is an important research area that faces different challenges in the pre-processing stage of image processing, particularly in boundary detection stage. In edge detection, the possibility of achieving high quality images significantly depends on the fitting threshold values, which are generally selected using canny method, and these threshold values may vary, based on the type of images and the applications chosen. This research work presents a novel idea of establishing a hybrid particle swarm optimization algorithm, which is a combination of PSO with the behavioural pattern of cellular organism in canny method, that defines an objective to find optimal threshold values for the implementation of double thresholding hysteresis method, which is viewed as a non-linear complex problem. The attempt to incorporate the model has minimized the problem of quick convergence of PSO algorithm which has improved the detection of broken edges. The efficiency of the proposed algorithm is proved through the experimental observation, done in Tamil sign images to indicate the better performance of canny operator by introducing new variant based PSO.
Volume: 6
Issue: 5
Page: 2158-2166
Publish at: 2016-10-01

PAPR Reduction for Improved Efficiency of OFDM Modulation for Next Generation Communication Systems

10.11591/ijece.v6i5.pp2310-2321
Shatrughna Prasad Yadav , Subhash Chandra Bera
Highly linear power amplifiers are required for transferring   large amount of data for future communication. Orthogonal frequency division multiplexing (OFDM) provides high data rate transmission capability with robustness to radio channel impairments. It has been widely accepted for future communication for different services. But, it suffers from high value of peak-to-average power ratio (PAPR). High value of PAPR drives high power amplifier into its saturation region and causes it to operate in the nonlinear region.  In this paper, comparative study of four different PAPR reduction techniques: clipping and filtering (CF), selective mapping  method (SLM), partial transmit sequence (PTS) and DFT- spread technique  have been done. Mathematical modeling and Matlab simulations have been performed to arrive at the results with 4 QAM modulation format and 1024 number of sub carriers. At 0.01 % of complementary cumulative distribution function (CCDF) significant reduction of 11.3, 3.5, 3.4 and 1.0 dB have been obtained with DFT- spread, SLM, PTS and CF techniques respectively.
Volume: 6
Issue: 5
Page: 2310-2321
Publish at: 2016-10-01

A New Phase Current Profiling with FLC f or Torque Optimization of 12/8 SRM

10.11591/ijece.v6i5.pp1948-1955
Sihem Saidani , Mohamed Radhouan Hachicha , Moez Ghariani
The switched reluctance machine against its several merits such as simplicity, robustness, less cost manufacturing and large speed still suffers from its undesirable torque ripple and acoustic noise. Compared to different candidates of hybrid and electric vehicle engine, the frequency of use of SRM in traction drives is improved with the different optimizing torque oscillation solutions. Most of studies used the generic or specific model of switched reluctance machine in the Simulink library (6/4,8/6 and 10/8). Despite, a new non linear model simply implemented in Simulink tool usinga static finite element analysis a previous study is used in this work. Hence, a 12/8 non linear SRM drive system is simulated using MATLAB toolbox tested with an intelligent controller (FLC) in order to minimize the torque ripple of an oriented starter –alternator application of a hybrid vehicle.
Volume: 6
Issue: 5
Page: 1948-1955
Publish at: 2016-10-01

Monitoring of Landslides in Mountainous Regions based on FEM Modelling and Rain Gauge Measurements

10.11591/ijece.v6i5.pp2106-2113
Quoc-Anh Gian , Dinh-Chinh Nguyen , Duc-Nghia Tran , Duc-Tan Tran
Vietnam is a country heavily influenced by climate change. The effect of climate change leads to a series of dangerous phenomena, such as landslides. Landslides occur not only in the mountainous province, but also in Delta provinces, where hundreds of landslides are reported annually in the North-Western provinces of Vietnam. These events have catastrophic impact to the community as well as the economy. In mountainous areas, the conditions for landslides to occur are met frequently, especially after heavy rains or geological activity, causing harm to the community as well as damaging or destroying much needed infrastructure and key transport routes. However, in Vietnam, investment in mountainous regions has been often lower than in urban areas. The meteorology monitoring and forecasting systems are ill equipped and overloaded, so they cannot deliver earlier and more accurate forecasts for complex weather events, unable to provide timely warnings. It can be seen that in countries that landslide often occur, researchers have been trying to develop low cost and efficient landslide detection system. This paper precisely addressed the problems mentioned, by designing and implementing an efficient and reliable Landslide Monitoring and Early Warning (LMnE) system based on the 3G/2G mobile communication system, and a rain gauge at the field site along with a carefully FEM (finite element method) simulation using the rain density information on the server. The system uses advanced processing algorithms combining obtained data at the central station.
Volume: 6
Issue: 5
Page: 2106-2113
Publish at: 2016-10-01

Hover Position of Quadrotor Based on PD-like Fuzzy Linear Programming

10.11591/ijece.v6i5.pp2251-2261
Iswanto Iswanto , Oyas Wahyunggoro , Adha Imam Cahyadi
The purpose of this paper is to present the altitude control algorithm for quadrotor to be able to fly at a particular altitude. Several previous researchers have conducted studies on quadrotor altitude by using PID control but there are problems in the overshoot and oscillation. To optimize the control, tunning on PID algorithm must be first conducted to determine proportional and derivative constants. Hence, the paper presents altitude control modification by using PID-like fuzzy without tuning. The PID algorithm is a control algorithm for linear systems. While, system to be controlled is a non-linear, so that linearization is needed by using equilibrium. The proposed algorithm is a modification of the PID algorithm used as an altitude control which enables quadrotor to be stable when hovering. The algorithm used is not PID algorithm with tuning using fuzzy, but this is a single input single output (SISO) control PID-like fuzzy linear programming. The result of the research shows that quadrotor can hover in a rapid raise time, steady state and settling time without performing overshoot and oscillation.
Volume: 6
Issue: 5
Page: 2251-2261
Publish at: 2016-10-01

Trust-Based Privacy for Internet of Things

10.11591/ijece.v6i5.pp2396-2402
Vera Suryani , Selo Sulistyo , Widyawan Widyawan
Internet of Things or widely known as IOT makes smart objects become active participants in the communication process between objects and their environment. IoT services that utilize Internet connection require solutions to a new problem: security and privacy. Smart objects and machine-to-machine communications in IOT now become interesting research, including that related to security. Privacy, which is a safe condition in which object is free from interference from other objects, is one of the important aspects in IOT. Privacy can be implemented using various ways for examples by applying encryption algorithms, restrictions on access to data or users, as well as implementing rules or specific policy. Trustable object selection is one technique to improve privacy. The process of selecting a trustable object can be done based on past activities or trust history of the object, also by applying a threshold value to determine whether an object is "trusted" or not. Some researchers have studied this approach. In this study, the selection processes of trustable objects are calculated using Modified Ant Colony algorithm. The simulation was performed and resulted in declining graphic trend but stabilized in certain trust value.
Volume: 6
Issue: 5
Page: 2396-2402
Publish at: 2016-10-01

A Modulation Scheme for Floating Source Multilevel Inverter Topology with Increased Number of Output Levels

10.11591/ijece.v6i5.pp1985-1993
Hussain M. Bassi
This paper presented and studied a new switching scheme for floating source multilevel inverters to produce more levels with the same number of switching devices. In the proposed scheme, the function of the dc sources, except the inner one, is to build up square wave or blocks that is close in the shape to the desired sinusoidal wave. The job of the inner switching devices is to increase the number of the levels to produce smother sinusoidal wave in the inverter output. This job can be done by adding or subtracting the value of the inner dc source to/from the blocks. The topology used in this paper is based on the conventional floating source multi-level inverter using two legs. This topology and modulation technique show substantial reduction in the total harmonics distortion when the modulation technique is the hybrid method. The performance of the proposed switching scheme in generating more levels has been evaluated by PSCAD/EMTDC simulation.
Volume: 6
Issue: 5
Page: 1985-1993
Publish at: 2016-10-01

EETA: An Energy Efficient Transmission Alignment for Wireless Sensor Network Applications

10.11591/ijece.v6i5.pp2345-2351
Sangsoon Lim , Hayoung Oh
Energy conserving MAC protocols performing adaptive duty-cycling mechanism have been widely studied to improve the energy efficiency in Wireless Sensor Networks (WSNs). In particular, several asynchronous Low Power Listening (LPL) MAC protocols such as B-MAC, X-MAC and ContikiMAC transmit a long preamble or consecutive data packets for an efficient rendezvous between senders and receivers. However, the rendezvous results in the challenging problem of unnecessary channel utilization since the senders occupy a large portion of the medium. Furthermore, when a traffic generation time overlaps with other neighbouring nodes, they frequently encounter spatially-correlated contention incurring excessive channel contention. In this paper, we propose a novel traffic distribution scheme called an Energy Efficient Transmission Alignment (EETA), that shifts a traffic generation time of the application layer. By using a MAC layer feedback including contention information, the cross-layer framework determines whether the node delays its transmission or not. EETA is robust from the heavy contending environment due to its traffic distribution feature. We evaluate the performance of EETA through diverse experiments on the TelosB platform. The results show that EETA improves the overall energy efficiency by up to 35%, and reduces the latency by up to 48% compared to the existing scheme.
Volume: 6
Issue: 5
Page: 2345-2351
Publish at: 2016-10-01

Emotional Facial Expression Based On Action Units and Facial Muscle

10.11591/ijece.v6i5.pp2478-2487
Ahmad Hoirul Basori , Hani Moaiteq Abdullah AlJahdali
The virtual human play vital roles in virtual reality and game. The process of Enriching the virtual human through their expression is one of the aspect that most researcher studied and improved. This study aims to demonstrate the combination of facial action units (FACS) and facial muscle to produce a realistic facial expression. The result of experiment succeed on producing particular expression such as anger, happy, sad which are able to convey the emotional state of the virtual human. This achievement is believed to bring full mental immersion towards virtual human and audience. The future works will able to generate a complex virtual human expression that combine physical factos such as wrinkle, fluid dynamics for tears or sweating.
Volume: 6
Issue: 5
Page: 2478-2487
Publish at: 2016-10-01

Power-Flow Development Based on the Modified Backward-Forward for Voltage Profile Improvement of Distribution System

10.11591/ijece.v6i5.pp2005-2014
Suyanto Suyanto , Citra Rahmadhani , Ontoseno Penangsang , Adi Soeprijanto
Unbalanced three-phase radial distribution system has a complex problem in power system. It has many branches and it is sometimes voltage profile’s not stable at every end branches. For improvement of voltage profile, it can be performed by penetrating of a distributed generation models. Information of voltage profile can be gained by study of power flow.  The Modified Backward-Forward is one of the most widely used methods of development of power flow and has been extensively used for voltage profile analysis. In this paper, a study of power flow based on the Modified Backward-Forward method was used to capture the complexities of unbalanced three phase radial distribution system in the 20 kV distribution network in North Surabaya city, East Java, Indonesia within considering distributed generation models. In summary, for the informants in this study, the Modified Backward-Forward method has had quickly convergence and it’s just needed 3 to 5 iteration of power flow simulation which’s compared to other power flow development methods. Distributed Generation models in the modified the modified 34 BUS IEEE system and 20 kV distribution network has gained voltage profile value on limited range. One of the more significant findings to emerge from this development is that the Modified Backward-Forward method has average of error voltage about 0.0017 % to 0.1749%.
Volume: 6
Issue: 5
Page: 2005-2014
Publish at: 2016-10-01

Adaptive Speech Compression Based on Discrete Wave Atoms Transform

10.11591/ijece.v6i5.pp2150-2157
Bousselmi Souha , Aloui Nouredine , Cherif Adnane
This paper proposes a new adaptive speech compression system based on discrete wave atoms transform. First, the signal is decomposed on wave atoms, then wave atom coefficients are truncated using a new adaptive thresholding which depends on the SNR estimation. The thresholded coefficients are quantized using Max Lloyd scalar quantizer. Besides, they are encoded using zero run length encoding followed by Huffman coding. Numerous simulations are performed to prove the robustness of our approach. The results of current work are compared with wavelet based compression by using objective criteria, namely CR, SNR, PSNR and NRMSE. This study shows that the wave atoms transform is more appropriate than wavelets transform since it offers a higher compression ratio and a better speech quality.
Volume: 6
Issue: 5
Page: 2150-2157
Publish at: 2016-10-01

Single Perceptron Model for Smart Beam forming in Array Antennas

10.11591/ijece.v6i5.pp2300-2309
K.S. Senthilkumar , K. Pirapaharan , P.R.P Hoole , R.R.H Hoole
In this paper, a single neuron neural network beamformer is proposed. A perceptron model is designed to optimize the complex weights of a dipole array antenna to steer the beam to desired directions. The objective is to reduce the complexity by using a single neuron neural network and utilize it for adaptive beamforming in array antennas. The selection of nonlinear activation function plays the pivotal role in optimization depends on whether the weights are real or complex. We have appropriately proposed two types of activation functions for respective real and complex weight values.   The optimized radiation patterns obtained from the single neuron neural network are compared with the respective optimized radiation patterns from the traditional Least Mean Square (LMS) method. Matlab is used to optimize the weights in neural network and LMS method as well as display the radiation patterns.
Volume: 6
Issue: 5
Page: 2300-2309
Publish at: 2016-10-01
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