The current air traffic management systems are not able to manage the enormous capacities of air ... more The current air traffic management systems are not able to manage the enormous capacities of air traffic perfectly and have not sufficient capability to service different types of flights. Free flight is a new concept presented potentially to solve problems in the current air traffic management system. The free flight concept changes the current centralized and command-control airspace system (between air traffic controllers and pilots) to a distributed system that allows pilots choose their own flight paths more efficiently, and also plan for their flight with high performance themselves. Despite of many advantages of free flight (such as less fuel consumption, minimum delays and the reduction of the workload of the air traffic control centers), it cause many problems such as conflicts (collisions) between different aircrafts. In this paper, we presented a model for conflict detection and resolution between aircrafts in air traffic management using graph coloring problem’s concept. In fact, we mapped the congestion area to a corresponding graph, and then addressed to find a reliable and optimal coloring for this graph using a prioritization method.
Modeling dynamic networks has attracted much interest in recent years, which helps understand net... more Modeling dynamic networks has attracted much interest in recent years, which helps understand networks’ behavior. Many works have been dedicated to modeling discrete-time networks, but less work is done for continuous-time networks. Point processes as powerful tools for modeling discrete events in continuous time have been widely used for modeling events over networks and their dynamics. These models have solid mathematical assumptions, making them interpretable but decreasing their generalizability for different datasets. Hence, neural point processes were introduced that don’t have strong assumptions on generative functions. However, these models can be impractical in the case of a large number of event types. This research presents a comparative study of different point process (Hawkes) models for continuous-time networks. Furthermore, a previously introduced neural point process (neural Hawkes) model is applied for modeling network interactions. In this work, network clustering ...
Ground-based weather radar can observe a wide range with a high spatial and temporal resolution. ... more Ground-based weather radar can observe a wide range with a high spatial and temporal resolution. They are beneficial to meteorological research and services by providing valuable information. Recent weather radar data related research has focused on applying machine learning and deep learning to solve complicated problems. It is a well-known fact that an adequate amount of data is a positively necessary condition in machine learning and deep learning. Generative adversarial networks (GANs) have received extensive attention for their remarkable data generation capacity, with a fascinating competitive structure having been proposed since. Consequently, a massive number of variants have been proposed; which model is adequate to solve the given problem is an inevitable concern. In this paper, we propose exploring the problem of radar image synthesis and evaluating different GANs with authentic radar observation results. The experimental results showed that the improved Wasserstein GAN i...
Nowadays, due to the emergence of big data and its critical rule in most applications, data avail... more Nowadays, due to the emergence of big data and its critical rule in most applications, data availability is big concern. For some applications, even the lack of a piece of information is not acceptable and have great drawbacks on results. Therefore, the storage reliability and guarantee of rapid data recovery is one of the main concerns. In case of disk failure, due to high storage volume, a lot of time is required for data recovery and this greatly decreases data availability. A new storage schema named RSS-RAID is presented in this paper. In this schema, disks are divided into groups with the same number of disks and data are stored as strips between disks with a particular algorithm based on a reversible hashing function. One advantage of proposed schema in comparison with similar models is that the location of the blocks is pre-known and when disk failure happens, number of missing blocks is clearly known and recovery algorithm do not need to search copies of missed blocks on th...
Cloud computing has become a well-known platform for solving big data and complex problems such a... more Cloud computing has become a well-known platform for solving big data and complex problems such as workflow applications. Infrastructure as a Service (IaaS) from the cloud is a suitable platform to solve these problems as it can potentially provide a nearly unlimited amount of resources using virtualization technology with a pay-peruse cost model. Various Quality of Service (QoS) objectives, such as cost and time, have been considered individually for workflow scheduling. In this paper, we proposed two energy-efficient heuristic algorithms with budget-deadline constraints that are appropriate for resources with Dynamic Voltage and Frequency Scaling (DVFS) enabled, as well as those that do not support DVFS. They are Budget Deadline Constrained Energyaware (BDCE) and Budget Deadline DVFS-enabled energy-aware (BDD) algorithms for the cloud. Furthermore, they acquire affordable cost, faster scheduling length, and higher energy-saving ratio. Various evaluation metrics like success rate, cost and time ratios, energy consumption, utilization rate, and energy-saving ratio are utilized to evaluate the performance of the proposed algorithms. The obtained results are compared with budget-deadline constraints methods, such as BDSD, DBCS, and BDHEFT, as well as two other energy-efficient deadline-constrained algorithms, namely, ERES and Safari's algorithm in various scenarios on scientific workflow applications.
Computer Engineering and Applications Journal, 2015
The increasing energy consumption has become a major concern in cloud computing due to its cost a... more The increasing energy consumption has become a major concern in cloud computing due to its cost and environmental damage. Virtual Machine placement algorithms have been proven to be very effective in increasing energy efficiency and thus reducing the costs. In this paper we have introduced a new priority routing VM placement algorithm and have compared it with PABFD (power-aware best fit decreasing) on CoMon dataset using CloudSim for simulation. Our experiments show the superiority of our new method with regards to energy consumption and level of SLA violations measures and prove that priority routing VM placement algorithm can be effectively utilized to increase energy efficiency in the clouds.
Database administrators need to compute closure of functional dependencies (FDs) for normalizatio... more Database administrators need to compute closure of functional dependencies (FDs) for normalization of database systems and enforcing integrity rules. Colored Petri net (CPN) is a powerful formal method for modelling and verification of various systems. In this paper, we modelled Armstrong's axioms for automatic proof generation of a new FD rule from initial FD rules using CPN. For this purpose, a CPN model of Armstrong's axioms presents and initial FDs considered in the model as initial color set. Then we search required FD in the state space of the model via model checking. If it exists in the state space, then a recursive ML code extracts the proof of this FD rule using further searches in the state space of the model.
Existence of design faults is a source of failure in the system. Detection and removal of faults ... more Existence of design faults is a source of failure in the system. Detection and removal of faults in design phase prohibits increase of cost and time of system development. Formal methods are used for proving behavioral properties of systems. Formal methods can be used in crux design of computer games to ensure absence of deadlock, guarantee of answer's existence and to determine complexity of crux. Hierarchical colored Petri net is a formal method that can be used to evaluate cruxes of computer games such as path planning puzzle games. Unblock me game is modeled as a case study and automatic analysis of its two cruxes are studied in this paper. Modeling of game is done hierarchically. New approaches for eliminating state space explosion problem and decreasing running time of model is presented in this paper. Modeling is done with aim of automatic state space analysis of the system and required functions for proving behavioral properties are implemented. This paper is presented a...
An approach for improving quality and performance of collaborative filtering-based recommender sy... more An approach for improving quality and performance of collaborative filtering-based recommender systems is proposed in this paper. A slight change on similarity metric is proposed. To obtain more accurate similarity measurement between two users, similarity measurement method needs a well-chosen weight vector. Different weight vectors could be employed based on the recommender system and the taste of users, but only some of them are suitable. To obtain the best results we have to find the most suitable weight vector among all possible ones. A meta-heuristic algorithm has been introduced to find near optimal weight vector. Cuckoo optimization algorithm is used to obtain optimized weight vector. The results are promising and satisfactory. Our results are compared with the results of previous approaches to verify effectiveness of new proposed method.
Autonomous mobile actors are under attention of researchers for having numeral applications. The ... more Autonomous mobile actors are under attention of researchers for having numeral applications. The way of placement and movement of actors in environment is very important for appropriate service of events. Two approaches, named settlement in center and settlement in place are introduced in this paper for evaluating placement location and movement method of actors in environment. Probability mass function of traversed distance for servicing events of environment by an actor for two approaches are mathematically proved step by step. Diagrams of simulations' results and functions are drawn simultaneously and show that results of both methods completely confirms. Simulations' results show that average displacement of actor in settlement in center approach in comparison with settlement in place approach is more; instead, average distance of events from center of area is less than average distance from location of previous event. In remaining, service of the events by a mobile acto...
Psychological and behavioral evidence suggests that home sports activity reduces negative moods a... more Psychological and behavioral evidence suggests that home sports activity reduces negative moods and anxiety during lockdown days of COVID-19. Low-cost, nonintrusive, and privacy-preserving smart virtual-coach Table Tennis training assistance could help to stay active and healthy at home. In this paper, a study was performed to develop a Forehand stroke’ performance evaluation system as the second principal component of the virtual-coach Table Tennis shadow-play training system. This study was conducted to show the effectiveness of the proposed LSTM model, compared with 2DCNN and RBF-SVR time-series analysis and machine learning methods, in evaluating the Table Tennis Forehand shadow-play sensory data provided by the authors. The data was generated, comprising 16 players’ Forehand strokes racket’s movement and orientation measurements; besides, the strokes’ evaluation scores were assigned by the three coaches. The authors investigated the ML models’ behaviors changed by the hyperpara...
As Wireless Mesh Networks (WMNs) are growing day-by-day, a seamless and secure handoff is gaining... more As Wireless Mesh Networks (WMNs) are growing day-by-day, a seamless and secure handoff is gaining significant importance for supporting multi-hop WMNs. On this point, various authentication protocols, such as the ticket-based handoff authentication, for wireless mesh networks have been proposed. Modeling and formal verification of the aforementioned protocol using CPN Tools and ASK-CTL statement are the purposes of this paper. To this aim, the resistance of the protocol against attacks, such as the man in the middle attack is investigated and then, it is concluded that it is secure.
The sensory data were collected from a total of 16 Table Tennis players mixed gender, aged betwee... more The sensory data were collected from a total of 16 Table Tennis players mixed gender, aged between 19 and 38 years, who used the IMU mounted Racket. We considered the Basic, Topspin, and Push as the sample type of performed Forehand strokes. The Table Tennis Forehand strokes quality evaluation values were collected from a total of 3 Table Tennis highly educated and ranked coaches who manually scored the performed strokes based on the experiment evaluation metrics. The players used the IMU mounted racket when samples were collecting. Each subject's performance was evaluated, scored, and labeled by the coaches who placed around Table Tennis's table. Acquiring simultaneously by the Racket, the strokes' evaluation metrics values, and their labels, each player carried out a predetermined stroke performing protocols when data was gathering. Capturing order of the samples are: 1) the players started performing strokes, 2) paused for five seconds by the coaches at the end of each stroke performing, 3) stored the sensory data by the software into a single CSV file, 4) labeled and scored the players' performance by the coaches manually.
Formal methods are widely used for studying and verifying characteristics of concurrency control ... more Formal methods are widely used for studying and verifying characteristics of concurrency control mechanisms (CCMs) and protocols in distributed databases. Colored Petri net (CPN) has high modeling capabilities and is one of the best methods for formal analysis and verification of CCMs. In this paper, a novel model of CCM based on two phase locking (2PL) using CPN has presented. State space analysis of model permits us to prove that all schedules of concurrent execution of transactions using 2PL in a case study is deadlock free nor not. Then a simple case study along with its state space analysis has presented. Results show that CPN is proper method for modeling CCM using 2PL and proving deadlock freeness property of all schedules of transactions.
The current air traffic management systems are not able to manage the enormous capacities of air ... more The current air traffic management systems are not able to manage the enormous capacities of air traffic perfectly and have not sufficient capability to service different types of flights. Free flight is a new concept presented potentially to solve problems in the current air traffic management system. The free flight concept changes the current centralized and command-control airspace system (between air traffic controllers and pilots) to a distributed system that allows pilots choose their own flight paths more efficiently, and also plan for their flight with high performance themselves. Despite of many advantages of free flight (such as less fuel consumption, minimum delays and the reduction of the workload of the air traffic control centers), it cause many problems such as conflicts (collisions) between different aircrafts. In this paper, we presented a model for conflict detection and resolution between aircrafts in air traffic management using graph coloring problem’s concept. In fact, we mapped the congestion area to a corresponding graph, and then addressed to find a reliable and optimal coloring for this graph using a prioritization method.
Modeling dynamic networks has attracted much interest in recent years, which helps understand net... more Modeling dynamic networks has attracted much interest in recent years, which helps understand networks’ behavior. Many works have been dedicated to modeling discrete-time networks, but less work is done for continuous-time networks. Point processes as powerful tools for modeling discrete events in continuous time have been widely used for modeling events over networks and their dynamics. These models have solid mathematical assumptions, making them interpretable but decreasing their generalizability for different datasets. Hence, neural point processes were introduced that don’t have strong assumptions on generative functions. However, these models can be impractical in the case of a large number of event types. This research presents a comparative study of different point process (Hawkes) models for continuous-time networks. Furthermore, a previously introduced neural point process (neural Hawkes) model is applied for modeling network interactions. In this work, network clustering ...
Ground-based weather radar can observe a wide range with a high spatial and temporal resolution. ... more Ground-based weather radar can observe a wide range with a high spatial and temporal resolution. They are beneficial to meteorological research and services by providing valuable information. Recent weather radar data related research has focused on applying machine learning and deep learning to solve complicated problems. It is a well-known fact that an adequate amount of data is a positively necessary condition in machine learning and deep learning. Generative adversarial networks (GANs) have received extensive attention for their remarkable data generation capacity, with a fascinating competitive structure having been proposed since. Consequently, a massive number of variants have been proposed; which model is adequate to solve the given problem is an inevitable concern. In this paper, we propose exploring the problem of radar image synthesis and evaluating different GANs with authentic radar observation results. The experimental results showed that the improved Wasserstein GAN i...
Nowadays, due to the emergence of big data and its critical rule in most applications, data avail... more Nowadays, due to the emergence of big data and its critical rule in most applications, data availability is big concern. For some applications, even the lack of a piece of information is not acceptable and have great drawbacks on results. Therefore, the storage reliability and guarantee of rapid data recovery is one of the main concerns. In case of disk failure, due to high storage volume, a lot of time is required for data recovery and this greatly decreases data availability. A new storage schema named RSS-RAID is presented in this paper. In this schema, disks are divided into groups with the same number of disks and data are stored as strips between disks with a particular algorithm based on a reversible hashing function. One advantage of proposed schema in comparison with similar models is that the location of the blocks is pre-known and when disk failure happens, number of missing blocks is clearly known and recovery algorithm do not need to search copies of missed blocks on th...
Cloud computing has become a well-known platform for solving big data and complex problems such a... more Cloud computing has become a well-known platform for solving big data and complex problems such as workflow applications. Infrastructure as a Service (IaaS) from the cloud is a suitable platform to solve these problems as it can potentially provide a nearly unlimited amount of resources using virtualization technology with a pay-peruse cost model. Various Quality of Service (QoS) objectives, such as cost and time, have been considered individually for workflow scheduling. In this paper, we proposed two energy-efficient heuristic algorithms with budget-deadline constraints that are appropriate for resources with Dynamic Voltage and Frequency Scaling (DVFS) enabled, as well as those that do not support DVFS. They are Budget Deadline Constrained Energyaware (BDCE) and Budget Deadline DVFS-enabled energy-aware (BDD) algorithms for the cloud. Furthermore, they acquire affordable cost, faster scheduling length, and higher energy-saving ratio. Various evaluation metrics like success rate, cost and time ratios, energy consumption, utilization rate, and energy-saving ratio are utilized to evaluate the performance of the proposed algorithms. The obtained results are compared with budget-deadline constraints methods, such as BDSD, DBCS, and BDHEFT, as well as two other energy-efficient deadline-constrained algorithms, namely, ERES and Safari's algorithm in various scenarios on scientific workflow applications.
Computer Engineering and Applications Journal, 2015
The increasing energy consumption has become a major concern in cloud computing due to its cost a... more The increasing energy consumption has become a major concern in cloud computing due to its cost and environmental damage. Virtual Machine placement algorithms have been proven to be very effective in increasing energy efficiency and thus reducing the costs. In this paper we have introduced a new priority routing VM placement algorithm and have compared it with PABFD (power-aware best fit decreasing) on CoMon dataset using CloudSim for simulation. Our experiments show the superiority of our new method with regards to energy consumption and level of SLA violations measures and prove that priority routing VM placement algorithm can be effectively utilized to increase energy efficiency in the clouds.
Database administrators need to compute closure of functional dependencies (FDs) for normalizatio... more Database administrators need to compute closure of functional dependencies (FDs) for normalization of database systems and enforcing integrity rules. Colored Petri net (CPN) is a powerful formal method for modelling and verification of various systems. In this paper, we modelled Armstrong's axioms for automatic proof generation of a new FD rule from initial FD rules using CPN. For this purpose, a CPN model of Armstrong's axioms presents and initial FDs considered in the model as initial color set. Then we search required FD in the state space of the model via model checking. If it exists in the state space, then a recursive ML code extracts the proof of this FD rule using further searches in the state space of the model.
Existence of design faults is a source of failure in the system. Detection and removal of faults ... more Existence of design faults is a source of failure in the system. Detection and removal of faults in design phase prohibits increase of cost and time of system development. Formal methods are used for proving behavioral properties of systems. Formal methods can be used in crux design of computer games to ensure absence of deadlock, guarantee of answer's existence and to determine complexity of crux. Hierarchical colored Petri net is a formal method that can be used to evaluate cruxes of computer games such as path planning puzzle games. Unblock me game is modeled as a case study and automatic analysis of its two cruxes are studied in this paper. Modeling of game is done hierarchically. New approaches for eliminating state space explosion problem and decreasing running time of model is presented in this paper. Modeling is done with aim of automatic state space analysis of the system and required functions for proving behavioral properties are implemented. This paper is presented a...
An approach for improving quality and performance of collaborative filtering-based recommender sy... more An approach for improving quality and performance of collaborative filtering-based recommender systems is proposed in this paper. A slight change on similarity metric is proposed. To obtain more accurate similarity measurement between two users, similarity measurement method needs a well-chosen weight vector. Different weight vectors could be employed based on the recommender system and the taste of users, but only some of them are suitable. To obtain the best results we have to find the most suitable weight vector among all possible ones. A meta-heuristic algorithm has been introduced to find near optimal weight vector. Cuckoo optimization algorithm is used to obtain optimized weight vector. The results are promising and satisfactory. Our results are compared with the results of previous approaches to verify effectiveness of new proposed method.
Autonomous mobile actors are under attention of researchers for having numeral applications. The ... more Autonomous mobile actors are under attention of researchers for having numeral applications. The way of placement and movement of actors in environment is very important for appropriate service of events. Two approaches, named settlement in center and settlement in place are introduced in this paper for evaluating placement location and movement method of actors in environment. Probability mass function of traversed distance for servicing events of environment by an actor for two approaches are mathematically proved step by step. Diagrams of simulations' results and functions are drawn simultaneously and show that results of both methods completely confirms. Simulations' results show that average displacement of actor in settlement in center approach in comparison with settlement in place approach is more; instead, average distance of events from center of area is less than average distance from location of previous event. In remaining, service of the events by a mobile acto...
Psychological and behavioral evidence suggests that home sports activity reduces negative moods a... more Psychological and behavioral evidence suggests that home sports activity reduces negative moods and anxiety during lockdown days of COVID-19. Low-cost, nonintrusive, and privacy-preserving smart virtual-coach Table Tennis training assistance could help to stay active and healthy at home. In this paper, a study was performed to develop a Forehand stroke’ performance evaluation system as the second principal component of the virtual-coach Table Tennis shadow-play training system. This study was conducted to show the effectiveness of the proposed LSTM model, compared with 2DCNN and RBF-SVR time-series analysis and machine learning methods, in evaluating the Table Tennis Forehand shadow-play sensory data provided by the authors. The data was generated, comprising 16 players’ Forehand strokes racket’s movement and orientation measurements; besides, the strokes’ evaluation scores were assigned by the three coaches. The authors investigated the ML models’ behaviors changed by the hyperpara...
As Wireless Mesh Networks (WMNs) are growing day-by-day, a seamless and secure handoff is gaining... more As Wireless Mesh Networks (WMNs) are growing day-by-day, a seamless and secure handoff is gaining significant importance for supporting multi-hop WMNs. On this point, various authentication protocols, such as the ticket-based handoff authentication, for wireless mesh networks have been proposed. Modeling and formal verification of the aforementioned protocol using CPN Tools and ASK-CTL statement are the purposes of this paper. To this aim, the resistance of the protocol against attacks, such as the man in the middle attack is investigated and then, it is concluded that it is secure.
The sensory data were collected from a total of 16 Table Tennis players mixed gender, aged betwee... more The sensory data were collected from a total of 16 Table Tennis players mixed gender, aged between 19 and 38 years, who used the IMU mounted Racket. We considered the Basic, Topspin, and Push as the sample type of performed Forehand strokes. The Table Tennis Forehand strokes quality evaluation values were collected from a total of 3 Table Tennis highly educated and ranked coaches who manually scored the performed strokes based on the experiment evaluation metrics. The players used the IMU mounted racket when samples were collecting. Each subject's performance was evaluated, scored, and labeled by the coaches who placed around Table Tennis's table. Acquiring simultaneously by the Racket, the strokes' evaluation metrics values, and their labels, each player carried out a predetermined stroke performing protocols when data was gathering. Capturing order of the samples are: 1) the players started performing strokes, 2) paused for five seconds by the coaches at the end of each stroke performing, 3) stored the sensory data by the software into a single CSV file, 4) labeled and scored the players' performance by the coaches manually.
Formal methods are widely used for studying and verifying characteristics of concurrency control ... more Formal methods are widely used for studying and verifying characteristics of concurrency control mechanisms (CCMs) and protocols in distributed databases. Colored Petri net (CPN) has high modeling capabilities and is one of the best methods for formal analysis and verification of CCMs. In this paper, a novel model of CCM based on two phase locking (2PL) using CPN has presented. State space analysis of model permits us to prove that all schedules of concurrent execution of transactions using 2PL in a case study is deadlock free nor not. Then a simple case study along with its state space analysis has presented. Results show that CPN is proper method for modeling CCM using 2PL and proving deadlock freeness property of all schedules of transactions.
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