Performance

Open Access Article

1 - Network RAM Based Process Migration for HPC Clusters
Hamid Sharifian msharifi msharifi

10.7508/jist.2013.01.006

Process migration is critical to dynamic balancing of workloads on cluster nodes in any high performance computing cluster to achieve high overall throughput and performance. Most existing process migration mechanisms are however unsuccessful in achieving this goal pr More

Process migration is critical to dynamic balancing of workloads on cluster nodes in any high performance computing cluster to achieve high overall throughput and performance. Most existing process migration mechanisms are however unsuccessful in achieving this goal proper because they either allow once-only migration of processes or have complex implementations of address space transfer that degrade process migration performance. We propose a new process migration mechanism for HPC clusters that allows multiple migrations of each process by using the network RAM feature of clusters to transfer the address spaces of processes upon their multiple migrations. We show experimentally that the superiority of our proposed mechanism in attaining higher performance compared to existing comparable mechanisms is due to effective management of residual data dependencies. Manuscript profile

Open Access Article

2 - Defense against SYN Flooding Attacks: A Scheduling Approach
Shahram Jamali Gholam Shaker

10.7508/jist.2014.01.007

The TCP connection management protocol sets a position for a classic Denial of Service (DoS) attack, called the SYN flooding attack. In this attack attacker sends a large number of TCP SYN segments, without completing the third handshaking step to quickly exhaust connec More

The TCP connection management protocol sets a position for a classic Denial of Service (DoS) attack, called the SYN flooding attack. In this attack attacker sends a large number of TCP SYN segments, without completing the third handshaking step to quickly exhaust connection resources of the victim server. Therefore it keeps TCP from handling legitimate requests. This paper proposes that SYN flooding attack can be viewed metaphorically as result of an unfair scheduling that gives more opportunity to attack requests but prevents legal connections from getting services. In this paper, we present a scheduling algorithm that ejects the half connection with the longest duration, when number of half open connections reaches to the upper bound. The simulation results show that the proposed defense mechanism improves performance of the under attack system in terms of loss probability of requests and share of regular connections from system resources. Manuscript profile

Open Access Article

3 - Tracking Performance of Semi-Supervised Large Margin Classifiers in Automatic Modulation Classification
Hamidreza Hosseinzadeh Farbod Razzazi Afrooz Haghbin

10.7508/jist.2014.04.007

Automatic modulation classification (AMC) in detected signals is an intermediate step between signal detection and demodulation, and is also an essential task for an intelligent receiver in various civil and military applications. In this paper, we propose a semi-superv More

Automatic modulation classification (AMC) in detected signals is an intermediate step between signal detection and demodulation, and is also an essential task for an intelligent receiver in various civil and military applications. In this paper, we propose a semi-supervised Large margin AMC and evaluate it on tracking the received signal to noise ratio (SNR) changes to classify all forms of signals in a cognitive radio environment. To achieve this objective, two structures for self-training of large margin classifiers were developed in additive white Gaussian noise (AWGN) channels with priori unknown SNR. A suitable combination of the higher order statistics and instantaneous characteristics of digital modulation are selected as effective features. Simulation results show that adding unlabeled input samples to the training set, improve the tracking capacity of the presented system to robust against environmental SNR changes. Manuscript profile

Open Access Article

4 - Statistical Analysis of Different Traffic Types Effect on QoS of Wireless Ad Hoc Networks
Mahmood Mollaei Gharehajlu Saadan Zokaei Yousef Darmani

10.7508/jist.2015.01.002

IEEE 802.11 based wireless ad hoc networks are highly appealing owing to their needless of infrastructures, ease and quick deployment and high availability. Vast variety of applications such as voice and video transmission over these types of networks need different net More

IEEE 802.11 based wireless ad hoc networks are highly appealing owing to their needless of infrastructures, ease and quick deployment and high availability. Vast variety of applications such as voice and video transmission over these types of networks need different network performances. In order to support quality of service for these applications, characterizing both packets arrival and available resources are essential. To address these issues we use Effective Bandwidth/Effective Capacity theory which expresses packet arrival and service model statistically. Effective Bandwidth asymptotically represents arrival traffic specifications using a single function. Also, Effective Capacity statistically describes service model of each node. Based on this theory, at first we modeled each node’s service as an ON/OFF process. Then a new closed form of Effective Capacity is proposed which is a simple function and is dependent on a few parameters of the network. Afterward the performance of different traffic patterns such as constant bit rate, Poisson and Markov Modulated Poisson process are statistically evaluated in the case of both single and aggregate traffic modes. Using the proposed model we will show that traffic pattern affects QoS parameters even if all models have the same average packet arrival rate. We prove the accuracy of our model by a series of simulations which are run using NS2 simulator. Manuscript profile

Open Access Article

5 - Investigating the Effect of Functional and Flexible Information Systems on Supply Chain Operation: Iran Automotive Industry
Abbas Zareian Iraj Mahdavi Hamed Fazlollahtabar

10.7508/jist.2017.19.005

This research studies the relationship between supply chain and information system strategies, their effects on supply chain operation and functionality of an enterprise. Our research encompasses other ones because it uses a harmonic structure between information syst More

This research studies the relationship between supply chain and information system strategies, their effects on supply chain operation and functionality of an enterprise. Our research encompasses other ones because it uses a harmonic structure between information systems and supply chain strategies in order to improve supply chain functionality. The previous research focused on effects of information systems on modification of the relationship between supply chain strategies and supply chain function. We decide to evaluate direct effects of information systems on supply chain strategies. In this research, we show that information systems strategy to improve the relationship between supply chain and supply chain strategies will be. Therefore, it can be said that creating Alignment between informational system strategy and supply chain strategies finally result in improvement of supply chain functionality and company’s operation. Manuscript profile

Open Access Article

6 - An SRN Based Approach for Performance Evaluation of Network Layer in Mobile Ad hoc Networks
meisam Yadollahzadeh tabari Ali A Pouyan

10.7508/jist.2018.04.006

The application of mobile ad hoc networks (MANET) in emergency and critical cases needs a precise and formal performance evaluation of these networks. Traditional simulation-based performance evaluators like NS-2 and OPNET usually need a considerable time for producing More

The application of mobile ad hoc networks (MANET) in emergency and critical cases needs a precise and formal performance evaluation of these networks. Traditional simulation-based performance evaluators like NS-2 and OPNET usually need a considerable time for producing high level performance metrics. Also there is no theoretical background for mentioned simulators, too. In this research, we propose a framework for performance evaluation of mobile ad hoc networks. The presented framework points to the network layer of MANETs using SRN (Stochastic Reward Nets) modeling tool as variation of generalized stochastic Petri net (GSPN). Based on decomposition technique it encompasses two separate models: one for analysis of data flowing process and the other for modeling routing process ; supposing AODV as a routing protocol that is worked out. To verify the presented model, an equivalence-based method is applied. The proposed SRN model has been quantified by deriving two performances metrics as Packet Delivery Ratio (PDR) and End-to-end Delay. Both metrics are also compared to the value obtained from NS-2 simulator versus different number of nodes and four packet generation rates. The results show the obtained values from presented SRN model well matched to the values generated from NS-2 simulator with a considerable lesser execution time. Manuscript profile

Open Access Article

7 - The Influence of ERP Usage on Organizational Learning: An Empirical Investigation
Faisal Aburub

10.7508/jist.2018.03.004

A number of different hotels have been seen to direct significant investment towards Enterprise Recourse Planning (ERP) systems with the aim of securing sound levels of organizational learning. As a strategic instrument, organizational learning has been recommended in t More

A number of different hotels have been seen to direct significant investment towards Enterprise Recourse Planning (ERP) systems with the aim of securing sound levels of organizational learning. As a strategic instrument, organizational learning has been recommended in the modern management arena as potentially able to achieve a competitive edge and as stabilizing the success of businesses. Learning, as an aim, is not only able to improve the skillset and knowledge of employees, but also achieving organizational growth and development, whilst also helping to build a dynamic learning organization. Organizational learning is especially important in modern-day firms, when staff might choose to leave or change their role owing to the view that knowledge-sharing could be detrimental to their own success. The present work seeks to examine the impact of ERP usage on organizational learning. A new research model has been presented, this model has been empirically investigated in the Jordanian hotel industry. 350 questionnaires were distributed across a total of 350 hotels. 317 questionnaires were returned. Structural equation modeling (AMOS 18) was used to analyze the data. The findings from the empirical findings emphasize that ERP usage has significant impact on organizational learning. In line with the study findings, various aspects of organizational learning, such as continuous learning, system perspective, openness and experimentation and transfer and integration are recognized as able to best encourage the use of ERP. Suggestions for future work and discussion on research limitations are also discussed. Manuscript profile

Open Access Article

8 - Cooperative Game Approach for Mobile Primary User Localization Based on Compressive Sensing in Multi-antenna Cognitive Sensor Networks
Maryam Najimi

10.7508/jist.2019.02.005

In this paper, the problem of joint energy efficient spectrum sensing and determining the mobile primary user location is proposed based on compressive sensing in cognitive sensor networks. By utilizing compressive sensing, the ratio of measurements for the sensing node More

In this paper, the problem of joint energy efficient spectrum sensing and determining the mobile primary user location is proposed based on compressive sensing in cognitive sensor networks. By utilizing compressive sensing, the ratio of measurements for the sensing nodes are considerably reduced. Therefore, energy consumption is improved significantly in spectrum sensing. The multi-antenna sensors is also considered to save more energy. On the other hand, multi-antenna sensor utilization is a proper solution instead of applying more sensors. The problem is formulated to maximize the network lifetime and find the mobile primary user position by sensors selection under the detection performance and accuracy of localization constraints. For this purpose, a cooperative game is proposed to study this problem. It is shown that with the proposed game, the network lifetime is maximized while the proper sensors which participate in spectrum sensing and primary user localization are determined. Simulation results show that the network lifetime is improved while the detection performance constraint is satisfied and the location of the primary user is determined with high accuracy. Manuscript profile

Open Access Article

9 - A New Non-Gaussian Performance Evaluation Method in Uncompensated Coherent Optical Transmission SystemsUniversity of Birjand
Seyed Sadra Kashef paeez azmi

10.7508/jist.2019.03.001

In this paper, the statistical distribution of the received quadrature amplitude modulation (QAM) signal components is analyzed after propagation in a dispersion uncompensated coherent optical fiber link. Two Gaussian tests, the Anderson-Darling and the Jarque-Bera have More

In this paper, the statistical distribution of the received quadrature amplitude modulation (QAM) signal components is analyzed after propagation in a dispersion uncompensated coherent optical fiber link. Two Gaussian tests, the Anderson-Darling and the Jarque-Bera have been used to measure the distance from the Gaussian distribution. By increasing the launch power, the received signal distribution starts to deviate from Gaussian. This deviation can have significant effects in system performance evaluation. The use of the Johnson s_U distribution is proposed for the performance evaluation of orthogonal frequency division multiplexing in an uncompensated coherent optical system. Here, the Johnson s_U is extended to predict the performance of multi-subcarrier and also single carrier systems with M-QAM signals. In particular, symbol error rate is derived based on the Johnson s_U distribution and performance estimations are verified through accurate Monte-Carlo simulations based on the split-step Fourier method. In addition, a new formulation for the calculation of signal to noise ratio is presented, which is more accurate than those proposed in the literature. In the linear region, the Johnson based estimations are the same as Gaussian; however, in the nonlinear region, Johnson s_U distribution power prediction is more accurate than the one obtained using the Gaussian approximation, which is verified by the numerical results. Manuscript profile

Open Access Article

10 - An Autonomic Software Defined Network (SDN) Architecture With Performance Improvement Considering
Alireza shirmarz Ali Ghaffari

10.29252/jist.8.30.121

SDN makes the network programmable, agile, and flexible with data and control traffic separating. This architecture consists of three layers which are application, control and data. The aim of our research is concentrated on the control layer to improve the performance More

SDN makes the network programmable, agile, and flexible with data and control traffic separating. This architecture consists of three layers which are application, control and data. The aim of our research is concentrated on the control layer to improve the performance of the network in an autonomic manner. In the first step, we have categorized the performance improvement researches based on network performance improvement solutions proposed in the recent papers. This performance improvement solution clustering is one of our contributions to our paper. The significant contribution in this paper is a novel autonomic SDN-based architecture to ameliorate the performance metrics including blocking probability (BP), delay, jitter, packet loss rate (PLR), and path utilization. Our SDN-based autonomic system consists of three layers (data, autonomic control, and Route learning) to separate the traffics based on deep neural networks (DNN) and to route the flows with the greedy algorithm. The autonomic SDN-based architecture which has proposed in this paper makes better network performance metrics dynamically. Our proposed autonomic architecture will be developed in the POX controller which has developed by python. Mininet is used for simulation and the results are compared with the commonly used SDN named pure SDN in this article. The simulation results show that our structure works better in a full-mesh topology and improves the performance metrics simultaneously. The average performance is improved by about %2.5 in comparison with pure SDN architecture based on the Area Under Curve (AUC) of network performance. Manuscript profile

Open Access Article

11 - Reliability Analysis of the Sum-Product Decoding Algorithm for the PSK Modulation Scheme
Hadi Khodaei Jooshin Mahdi Nangir

10.29252/jist.8.31.167

20.1001.1.23221437.2020.8.31.7.1

Iteratively decoding and reconstruction of encoded data has been considered in recent decades. Most of these iterative schemes are based on graphical codes. Messages are passed through space graphs to reach a reliable belief of the original data. This paper presents a p More

Iteratively decoding and reconstruction of encoded data has been considered in recent decades. Most of these iterative schemes are based on graphical codes. Messages are passed through space graphs to reach a reliable belief of the original data. This paper presents a performance analysis of the Low-Density Parity-Check (LDPC) code design method which approach the capacity of the Additive White Gaussian Noise (AWGN) model for communication channels. We investigate the reliability of the system under Phase Shift Keying (PSK) modulation. We study the effects and advantages of variation in the codeword length, the rate of parity-check matrix of the LDPC codes, and the number of iterations in the Sum-Product Algorithm (SPA). By employing an LDPC encoder prior to the PSK modulation block and the SPA in the decoding part, the Bit Error Rate (BER) performance of the PSK modulation system can improve significantly. The BER performance improvement of a point-to-point communication system is measured in different cases. Our analysis is capable for applying any other iterative message-passing algorithm. The code design process of the communication systems and parameter selection of the encoding and decoding algorithms are accomplished by considering hardware limitations in a communication system. Our results help to design and select paramours efficiently. Manuscript profile

Open Access Article

12 - Reliability Analysis of the Joint LDPC Decoding Algorithms over the Multiple Access Channels
Mahdi Nangir

10.52547/jist.9.36.33

20.1001.1.23221437.2021.9.36.8.9

The joint Low Density Parity-Check (LDPC) decoding schemes iteratively decode the received data from multiple channels. Mostly, the available data in different channels are correlated and there is kind of dependency between the links or channels. In recent decades, the More

The joint Low Density Parity-Check (LDPC) decoding schemes iteratively decode the received data from multiple channels. Mostly, the available data in different channels are correlated and there is kind of dependency between the links or channels. In recent decades, the graph-based codes have been considered for the communication network scenarios. The performance of these codes is close to the existing theoretical bounds and their complexity is not high which cause the possibility of real world implementation and exploitation. The Multiple Access Channel (MAC) scenario with multiple senders which aim to send correlated data to a single receiver is considered. An analysis on the reliability of the Bit Error Rate (BER) performance of the Joint Sum-Product (JSP) decoding algorithm is presented for a two-link case, which can be extended to higher number of links. The effect of parameter variations on the BER performance is studied. These parameters include: the total number of iterations, the codeword length, the total number of rounds, and the coding rate in the JSP algorithm. An optimal value of the parameters is selected during the design procedure of a communication network by considering its limitations and complexity criterion. The JSP algorithm is a reliable scheme for jointly decoding of noisy binary data from different origins. Manuscript profile

Open Access Article

13 - An ICT Performance Evaluation Model based on Meta-Synthesis Approach
Khatrehe Bamary Mohammad Reza Behboudi Tayebeh Abbasnjad

10.52547/jist.16445.10.39.229

20.1001.1.23221437.2022.10.39.8.2

Information and Communication Technology (ICT) is one of the key determinants for today’s organizational success. Therefore, companies spend a significant amount of money each year on ICT, while not being sure that they will get a good result. The purpose of this study More

Information and Communication Technology (ICT) is one of the key determinants for today’s organizational success. Therefore, companies spend a significant amount of money each year on ICT, while not being sure that they will get a good result. The purpose of this study is to identify the dimensions and indicators of ICT performance evaluation and suggesting a model for assessing it in organizations. This research is mainly a qualitative study with a meta-synthesis approach which uses the seven-stage qualitative method of Sandelowski and Barroso to systematically review the literature to find sub-indices (codes), indices (themes) and dimensions (categories) of ICT performance evaluation. The search of scientific databases with appropriate keywords found 516 articles, among them, 89 articles were chosen finally and used for analysis. Moreover, a questionnaire has been designed and answered by ICT experts and managers to determine the importance of each of the indicators of the model. Based on data analysis, the proposed ICT performance evaluation model has three dimensions: strategic, quality, and sustainability. The strategic dimension includes indicators of organization strategy, IT strategy, and alignment. The quality dimension includes maturity, and performance indicators; and finally, the sustainability dimension includes environmental, economic, and social indicators. For each of these indicators detailed list of sub-indices (104), which are substantial for evaluation of ICT performance in organizations, were identified and explained. Manuscript profile

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