International Journal of Information Technology and Computer Science @ijitcs
Статьи журнала - International Journal of Information Technology and Computer Science
Все статьи: 1235
Performance Comparison of Various Diversity Techniques using Matlab Simulation
Статья научная
Due to the time-varying nature of the wireless channel and presence of limited resources for the signal transmission, which faces various detrimental effects such as path-loss, delay spread, Doppler spread, shadowing and interference make it very difficult to achieve sufficient data rates. To combat the effect of multi-path fading in the wireless communication system, the diversity combining mechanism has been introduced. In this paper, we have developed an algorithm for the performance evaluation of various spatial diversity combing techniques by using Matlab simulation. The developed new algorithm combine all three diversity techniques such as maximal ratio combining (MRC), selection combining (SC) and equal gain combing (EGC) techniques The combined diversity techniques algorithm computes and compares the MRC, SC, and EGC combing techniques theoretically by using the Matlab simulation.
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Performance Evaluation of AODV, LHC-AODV, OLSR, UL-OLSR, DSDV Routing Protocols
Статья научная
Mobile ad hoc networks are type of wireless networks in which any kind of infrastructure is not used, i.e. there are no infrastructures such as routers or switches or anything else on the network that can be used to support the network structure and the nodes has mobility. The routing is particularly a challenging task in MANETs that selecting paths in a network along which to send network traffic. In this paper, the performance analysis is carried out on Ad-hoc On-demand Distance Vector (AODV), Limited Hop Count AODV (LHC-AODV), Optimized Link State Routing (OLSR), Unnecessary Loop OLSR (UL-OLSR) and Destination Sequenced Distance Vector (DSDV) protocols using NS2 simulator. The delay, throughput, and packet delivery ratio are the three common measures used for the comparison of the performance of above protocols.
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Performance Evaluation of Fake News Detection Models
Статья научная
The rapid spread of misinformation on social media platforms, especially Twitter, presents a challenge in the digital age. Traditional fact-checking struggles with the volume and speed of misinformation, while existing detection systems often focus solely on linguistic features, ignoring factors like source credibility, user interactions, and context. Current automated systems also lack the accuracy to differentiate between genuine and fake news, resulting in high rates of false positives and negatives. This study investigates the creation of a Twitter bot for detecting fake news using deep learning methodologies. The research assessed the performance of BERT, CNN, and Bi-LSTM models, along with an ensemble model combining their strengths. The TruthSeeker dataset was used for training and testing. The ensemble model leverages BERT's contextual understanding, CNN’s feature extraction, and Bi-LSTM’s sequence learning to improve detection accuracy. The Twitter bot integrates this ensemble model via the Twitter API for real-time detection of fake news. Results show the ensemble model significantly outperformed individual models and existing systems, achieving an accuracy of 98.24%, recall of 98.14%, precision of 98.42%, and an F1-score of 98.24%. These findings highlight that combining multiple models can offer an effective solution for real-time detection of misinformation, contributing to efforts to combat fake news on social media platforms.
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Performance Evaluation of I.T Project Management in Developing Countries
Статья научная
In recent past, IT industry has seen massive growth. However it is not much mature in developing countries, facing many challenges particularly in project management. As a result performance of IT industry is not up to the mark and unable to provide professional support as compared to internationally recognized standards to public and private sector organizations. There are many challenges such as shortage of skilled and experienced human resources and high employee turnover. Tough and competitive market condition requires the product to be extremely good in performance, timeline and accuracy. Effective project management and collaborative efforts of the Government and IT professionals can make highly successful market for IT projects. Success rate of private sector organizations is high as compared to public sector organizations in developing countries like Pakistan. In this research we have explored the performance of IT project management in public and private sector organizations of developing countries focusing Pakistan, to find out the reasons of project failure and success in both public and private sector organizations.
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Performance Evaluation of Index Schemes for Semantic Cache
Статья научная
In last decade of computing, a growing popularity for semantic cache schemes has been observed. Numerous techniques have been proposed for improved performance of semantic cache. Semantic cache is aimed towards reducing the network traffic load with the ability to address some queries without contacting the server. Semantic cache overcomes the limitations of previous page-caching and tuple-cache techniques. A prime concern of semantic cache includes query processing (query response-time) and cache management. The efficiency of semantic cache can be improved by using semantic indexing sachems. Semantic indexing sachems are segment based and hierarchical semantic indexing scheme. Both these sachems can improve the efficiency of query processing and cache management. In this paper, we have performed the evaluation of index schemes for Semantic Cache through the experimental study. Evaluations of these schemes are available in literature but experimental study is not available. Through this experiment, we have highlighted which technique is most suited in what kind of scenario.
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Статья научная
Nowadays, there are several models of computer systems finding their ways into various offices, houses, organizations as well as remote locations. Any slight malfunction of the computer system’s components could lead to loss of vital data and information. One of the sources of computer system malfunction is overheating of the electronic components. A common method of cooling a computer system is the use of cooling fan(s). Therefore, it is essential to have an appropriate control mechanism for the operation of computer system’s cooling fan in order to save energy, and prevent overheating. Failure to adopt a well designed and efficient performance controller could lead to the malfunction of a computer system. Presently, most controllers in computer systems are pulse width modulation based. That is, they make use of pulses in form of digits, 0 and 1. It was observed that inherent noise is still prevalent in the operation of computer system. Also, eventual breakdown of components is common. A new approach is therefore investigated through the use of fuzzy logic to serve as a base or platform to build an intelligent controller using a set of well defined rules to guide its operational performance. Mamdani-type fuzzy inference system and Sugeno-type fuzzy inference system were used with two input sets each and a single output function each. Simulation was carried out in MATLAB R2007a platform and operational performances of the two approaches were compared. Simulated results of the performances of the Mamdani-type fuzzy inference system based controller and the Sugeno-type fuzzy inference system based controller are presented accordingly.
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Performance Evaluation of Photovoltaic Models Based on a Solar Model Tester
Статья научная
The performances of 130 W (Solara PV) and 100 W (Sunworth PV) solar modules are evaluated using a single diode equivalent circuit. The equivalent circuit is able to simulate both the I–V and P–V characteristic curves, and is used to study the effect of the operating temperature, diode ideality factor, series resistance, and solar irradiance level on the model performance. The results of the PV characteristics curves are compared with the parameters from the manufacturing companies for each model. Afterwards, the Solara PV model is tested under different irradiance levels. The relationship between the model power versus its current under different irradiance levels is plotted, such that if the solar power meter (pyrheliometer) does not exist, the irradiance-current (G–I) curve can be used to measure solar radiation power without using the solar power meter. The measurement is achieved by moving the solar panel by a certain angle toward the solar radiation, and then measuring the corresponding current.
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Performance Evaluation of the Loop Buffer Switch Under Prioritized Traffic and Optical Regeneration
Статья научная
In this paper, an all-optical regenerator based, photonic packet switch architecture, which consists of the fiber loop for the storage of the contending packets, is considered. In the loop buffer, the available buffer space may not be fully utilized due to the limited re-circulation count of the data placed on buffer. This limit can be counteracted by placing a pool of regenerators inside the buffer. As optical regenerators are costly devices, hence they should be placed optimally in the buffer. The simulations results are presented by consider Prioritized and non – prioritized traffic. It is shown in the results that regeneration of data is essential if prioritized traffic has to be considered.
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Performance Evaluation of the Loop Buffer Switch under Prioritized Traffic
Статья научная
In this paper, optical loop buffer based architecture is discussed; with its advantages over other architectures. In general the performance of the switch is measured at physical and network layer. The physical layer analysis deals with power budget analysis, however, at the network layer; the performance is measured in terms of packet loss probability and average delay. To obtain more realistic performance at the network layer the QoS parameters need to be included. In this paper, a QoS parameter which is known as priority of the incoming packets is included and corresponding results are presented, and it has been found that even at the load of 0.7, packet loss probabilities on the order of 10-5 can be achieved.
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Performance Optimization in WBAN Using Hybrid BDT and SVM Classifier
Статья научная
Wireless Body Area Network has attracted significant research interest in various applications due to its self-automaton and advanced sensor technology. The most severe issue in WBAN is to sustain its Quality of Service (QoS) under the dynamic changing environment like healthcare, and patient monitoring system. Another critical issue in WBAN is heterogeneous packet handling in such resource-constrained network. In this paper, a new classifier having hybrid Binary Decision Tree and Support Vector Machine classifier is proposed to tackle these important challenges. The proposed hybrid classifier decomposes the N-class classification problem into N-1 sub-problems, each separating a pair of sub-classes. This protocol dynamically updates the priority of packet and node, adjusts data rate, packet transmission order and time, and resource distribution for the nodes based on node priority. The proposed protocol is implemented and simulated using NS-2 network simulator. The result generated for proposed approach shows that new protocol can outperform in a dynamic environment, and yields better performance by leveraging advantages of both the Binary Decision Tree in terms of efficient computation and Support Vector Machine for high classification accuracy. This hybrid classifier significantly reduces loss ratio and delay and increase packet delivery ratio and throughput.
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Performance analysis of LT codec architecture using different processor templates
Статья научная
Luby Transform (LT) code plays a vital role in binary erasure channel. This paper portrays the design techniques for implementation of LT codec using application specific instruction set processor (ASIP) design tools. In ASIP design, a common approach to increase the performance of processors is to boost the number of concurrent operations. Therefore, optimizations like strategy of input design, processor and compiler architecture are very useful phenomenon to enhance the performance of the application specific processor. Using Tensilica and OpenRISC processor design tools, this paper shows the response of LT codec architectures in terms of cycle counts and simulating time. Result shows that, the simulation speed of Tensilica is very high compared to the OpenRisc tool. Among different configurations of Tensilica tool, proposed ConnXD2 design took 1 M cycles per second and 135.66 ms to execute LT codec processor and XRC_D2MR configuration consumed only 9 iterations for successful decoding of LT encoded signal. Besides this, OpenRisc tool took 142K cycles and 6ms for executing LT encoder.
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Performance based Ranking Model for Cloud SaaS Services
Статья научная
Cloud computing systems provide virtualized resources that can be provisioned on demand basis. Enormous number of cloud providers are offering diverse number of services. The performance of these services is a critical factor for clients to determine the cloud provider that they will choose. However, determining a provider with efficient and effective services is a challenging task. There is a need for an efficient model that help clients to select the best provider based on the performance attributes and measurements. Cloud service ranking is a standard method used to perform this task. It is the process of arranging and classifying several cloud services within the cloud, then compute the relative ranking values of them based on the quality of service required by clients and the features of the cloud services. The objective of this study is to propose an enhanced performance based ranking model to help users choose the best service they need. The proposed model combines the attributes and measurements from cloud computing field and the well-defined and established software engineering field. SMICloud Toolkit has been used to test the applicability of the proposed model. The experimentation results of the proposed model were promising.
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Статья научная
Reusability is the quality of a piece of software, which enables it to be used again, be it partial, modified or complete. A wide range of modeling techniques have been proposed and applied for software quality predictions. Complexity and size metrics have been used to predict the number of defects in software components. Estimation of cost is important, during the process of software development. There are two main types of cost estimation approaches: algorithmic methods and non-algorithmic methods. In this work, using genetic programming which is a branch of evolutionary algorithms, a new algorithmic method is presented for software development cost estimation, using the implementation of this method; new formulas were obtained for software development cost estimation in which reusability of components is given priority. After evaluation of these formulas, the mean and standard deviation of the magnitude of relative error is better than related algorithmic methods such as COCOMO formulas.
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Performance of Frequency Domain DFE Using Subcarrier Allocation
Статья научная
Due to the usage of single carrier, the performance of SC-FDMA systems degrades in deep frequency selective fading channels. In this paper, we propose a structure of equalizer based on frequency domain decision feedback which could be used for multi-user SC-FDMA systems. This algorithm is applicable to various carrier allocations in multi-user systems such as localized allocation, distributed allocation, and frequency-hopping (FH) allocation. To reduce the complexity, it is not necessary to derive the inversion of matrix, which is required in the traditional decision feedback equalizer for single carrier frequency domain equalization (SC-FDE-DFE). Simulation results show that equalization has been achieved for FD-LE and FD-DFE with distribution mapping. This structure can be used in the broadcasting uplink channels with SC-FDMA scheme.
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Статья научная
In this paper, the performance of cellular communications based on the ambitious technology of High-Altitude Platforms (HAPs) is discussed when using tapered concentric circular arrays. The coverage cell will be described and designed with an efficient beamforming technique where the Hamming window is proposed as a tapering function and applied to the uniform concentric circular arrays (UCCA) for sidelobe reduction. Based on establishing some mapping curves, this novel tapering window is optimized in its parameters to have the lowest possible sidelobe level that can be 45 dB below the main lobe level. The optimum weights of Hamming window are found to be function of the number of elements of the innermost ring and the number of rings in the array. The cell power pattern is also discussed where the out-of-cell radiation is greatly reduced which in turns reduces the co-channel interference and improves the Carrier-to-Interference Ratio (CIR).
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Performance of Linear Block Coding for Multipath Fading Channel
Статья научная
This paper deals with the performance of linear block codes which provide a new paradigm for transmission over multipath fading channels. Multi path channel fading is the main enemy for any wireless communications system. Therefore, for any novel approach applied at any wireless communication system, its efficiency is measured according to its ability of mitigating the distortion caused by fading. It causes time dispersion to the transmitted symbols resulting in inter symbol interference (ISI). ISI inter symbol interference problem is a major impairment of the wireless communication channel. To mitigate the ISI problem and to have reliable communications in wireless channel, channel equalizer and channel coding technique is often employed. In this paper the BER (Bit Error Rate) performance is shown from analytically and by means of simulation for multipath dispersive channels. We have designed a channel equalizer using MLSE (Viterbi algorithm) in this paper for such a multipath channel (introducing inter symbol interferences) with BPSK modulation based on the assumption that the channel can be perfectly estimated at the receiver. Obviously the performance of channel coding in terms of BER is better than uncoded channel.
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Performance of Machine Learning Algorithms with Different K Values in K-fold Cross-Validation
Статья научная
The numerical value of k in a k-fold cross-validation training technique of machine learning predictive models is an essential element that impacts the model’s performance. A right choice of k results in better accuracy, while a poorly chosen value for k might affect the model’s performance. In literature, the most commonly used values of k are five (5) or ten (10), as these two values are believed to give test error rate estimates that suffer neither from extremely high bias nor very high variance. However, there is no formal rule. To the best of our knowledge, few experimental studies attempted to investigate the effect of diverse k values in training different machine learning models. This paper empirically analyses the prevalence and effect of distinct k values (3, 5, 7, 10, 15 and 20) on the validation performance of four well-known machine learning algorithms (Gradient Boosting Machine (GBM), Logistic Regression (LR), Decision Tree (DT) and K-Nearest Neighbours (KNN)). It was observed that the value of k and model validation performance differ from one machine-learning algorithm to another for the same classification task. However, our empirical suggest that k = 7 offers a slight increase in validations accuracy and area under the curve measure with lesser computational complexity than k = 10 across most MLA. We discuss in detail the study outcomes and outline some guidelines for beginners in the machine learning field in selecting the best k value and machine learning algorithm for a given task.
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Performance of a Slantlet Based OFDM Transceiver under Different Channel Conditions
Статья научная
A major goal of the next-generation wireless communication systems is the development of a reliable high-speed wireless communication system that supports high user mobility. Orthogonal Frequency Division Multiplexing (OFDM) system is one of the most promising technologies for current and future wireless communications that has drawn a lot of attention. OFDM usually achieved by Fast Fourier Transform (FFT). In this paper, Fast Fourier Transform (FFT) is replaced by SlantLet Transform (SLT) in order to reduce Inter-Carrier Interference (ICI), Inter-symbol Interference (ISI), and to improve the bandwidth efficiency by removing the Guard Interval (GI) needed in FFT-OFDM. The new structure was tested and compared with conventional FFT-based OFDM for Additive White Gaussian Noise (AWGN) channel, Flat Fading Channel (FFC), and multi-path Selective Fading Channel (SFC). Simulation tests were generated for different channels parameters values. The obtained results showed the proposed system has an improved Bit Error Rate (BER) performance compared with the reference system. For SFC the SLT-OFDM performs better than the FFT-OFDM on the lower SNR region, while the situation reverses with increasing SNR values.
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Phoenix: a framework to support transient overloads on cloud computing environments
Статья научная
This paper aims to present a computational framework capable of withstanding the effects produced by transient overloads on physical and virtual servers hosted on cloud computing environment. The proposed framework aims at automating management of virtual machines that are hosted in this environment, combining a proactive strategy, which performs load balancing when there is not overload of physical and/or virtual machines with a reactive strategy, which is triggered in the event of overload in these machines. On both strategies, it is observed the service level agreement (SLA) established for each hosted service according to the infrastructure as a service (IaaS) model. The main contribution of this paper is the implementation of a computational framework called Phoenix, capable of handling momentary overloads, considering the CPU, memory and network resources of physical and virtual machines and guaranteeing SLAs. The results demonstrate that Phoenix framework is effective, and it has outstanding performance in handling overloads virtual machine network, which has achieved the isolation of momentary overload on the physical machine preventing the propagation of their effects on the cloud.
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Phoneme concatenation method for myanmar speech synthesis system
Статья научная
This paper discusses the approach used to develop a Text-to-Speech (TTS) synthesis system for the Myanmar language. Concatenative method has been used to develop this TTS system using phoneme as the basic units for concatenation. In this proposed system, phoneme plays an important role so that Myanmar phoneme inventory is presented in detail. In Myanmar language, schwa is the only vowel that is allowed in a minor syllable or consonant that has half-sound of the original one. If these half sound can be handled, the TTS quality will be high. After analyzing the number of phoneme and half-sound consonant to be recorded, create the Myanmar phoneme speech database which contains total 157 phoneme speech sounds that can speech out for all Myanmar texts. These phonemes are fetched according to the result from the phonetic analysis modules and concatenated them by using proposed new phoneme concatenation algorithm. According to the experimental results, the system achieved the high level of intelligibility and acceptable level of naturalness. As the application area, it is intended for the resource limited device to use as language learning app and so on.
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