Temporal Justification Logic

Justification logics are modal-like logics with the additional capability of recording the reason, or justification, for modalities in syntactic structures, called justification terms. Justification logics can be seen as explicit counterparts to modal logics. The behavior and interaction of agents in distributed system is often modeled using logics of knowledge and time. In this paper, we sketch some preliminary ideas on how the modal knowledge part of such logics of knowledge and time could be replaced with an appropriate justification logic

Designing Precoding and Receive Matrices for Interference Alignment in MIMO Interference Channels

Interference is a key bottleneck in wireless communication systems. Interference alignment is a management technique that align interference from other transmitters in the least possibly dimension subspace at each receiver and provides the remaining dimensions for free interference signal. An uncoordinated interference is an example of interference which cannot be aligned coordinately with interference from coordinated part; consequently, the performance of interference alignment approaches are degraded. In this paper, we propose a rank minimization method to enhance the performance of interference alignment in the presence of uncoordinated interference sources. Firstly, to obtain higher multiplexing gain, a new rank minimization based optimization problem is proposed; then, a new class of convex relaxation is introduced which can reduce the optimal value of the problem and obtain lower rank solutions by expanding the feasibility set. Simulation results show that our proposed method can obtain considerably higher multiplexing gain and sum rate than other approaches in the interference alignment framework

Interference alignment for one-hop and two-hops MIMO systems with uncoordinated interference

Providing higher data rate is a momentous goal for wireless communications systems, while interference is an important obstacle to reach this purpose. To cope with this problem, interference alignment (IA) has been proposed. In this paper, we propose two rank minimization methods to enhance the performance of IA in the presence of uncoordinated interference, i.e., interference that cannot be properly aligned with the rest of the network and thus is a crucial issue. In this scenario, perfect and imperfect channel state information (CSI) cases are considered. Our proposed approaches employ the l2 and the Schatten-p norms to approximate the rank function, due to its non-convexity. Also, we propose a new convex relaxation to expand the feasible set of our optimization problem, providing lower rank solutions compared to other IA methods from the literature. In addition, we propose a modified weighted-sum method to deal with interference in the relay-aided MIMO interference channel, which employs a set of weighting parameters in order to find more solutions

Determination of the optimal amount of nitrous oxide injected into the engine in order to reduce emissions

Introduction: Nowadays the number of motor vehicles in large and small cities is growing. Increasing the number of motor vehicles leads to serious increase of the amount of environmental pollution and daily fuel consumption. Motor vehicle emissions that are known as the most air polluting emissions cause 50-90 percent of air pollution. With large increasd in the number of motor vehicles and their emissions todays, many researchers have investigated engine optimization in order to reduce emissions of motor vehicles. But due to the lack of affordable changes in the physical structure of the engine, it is not possible to create major changes in the amount of engine exhaust. Hence, in order to improve engine performance and reduce emissions, a lot of research has been carried out on changes in the fuel and engine inlet air. So, in this study a new method has been proposed and tested in order to detect changes in the charactristics of emissions. So, the effects of enriched nitrous oxide gas on the exhaust emissions of a spark-injection engine were investigated. In this way, a certain amount of Nitrous Oxide (N2O) gas was mixed with the engine inlet air (with concentration of 0, 4, 8, 12 and 16 percent) and it was injected to the engine. Then its effect was studied on emission parameters at various engine rotational speeds. Then, by using genetic algorithm, the optimal values of N2O concentration and engine rotational speed were determined to reach the minimum emission parameters. Materials and Methods: To measure the engine emission parameters including CO, CO2, HC and NOx, the expriments were conducted after preparing a system to inject inlet air with different percentages of N2O into an Otto engine (model: M13NI). In this study, the randomized complete block design was used to investigate the effect of N2O concentration (five levels) and engine rotational speed (three levels) on exhauste emission parameters. Each expriment was replicated 9 times. For statistical analysis, Duncan’s multiple range test and multivariate analysis of variance were performed by using SPSS Software. Also, each factor was modeled by polynomial equations and the obtained models were optimized in three dimensions by genetic algorithm method in MATLAB Software. After optimization ofeach emission parameter in the same time by multi-objective optimization regression, separately, and determination of the best value of N2O concentration in the inlet air andthe engine rotational speed, the optimizations were compared in order to obtain the minimum value of emission parameters. Results and discussion: The experimental results indicated that by increasing N2O concentration in the inlet air of motor vehicle engine, the amounts of CO and HC were significantly decreased and the amounts of CO2 and NOx were significantly increased. Also, the results of this study showed that increasing the engine rotational speed at the same time with increasing the N2O concentration caused a significant decrease in the amounts of CO, CO2, HC and NOx. The optimal amount of N2O concentration and engine rotational speed by genetic algorithm method were obtained to be14.545 % and 3184 rpm, respectively. Conclusions: The main conclusions obtained from this research are listed below: - The amount of N2O concentration in the engine fuelis the decisive factor for decreasing emissions. - By increasing N2O concentration in the inlet air of motor vehicle engine, the amounts of CO and HC were significantly decreased and the amounts of CO2 and NOx were significantly increased. - By increasing the engine rotational speed and N2O concentration, the amounts of CO, CO2, HC and NOx were decreased. - The optimal amount of N2O concentration and engine rotational speed were obtained to be 14.545 % and 3184 rpm, respectivelyby using the genetic algorithm method. For these values, based on regression models, concentration of CO and CO2, were obtained to be 0.056% and 12.5%, respectively. - The concentration of N2O and the optimum rotational speed of engine for CO gas were obtained to be 10.562% and 3749 rpm. - The concentration of N2O and the optimum rotational speed of the engine for CO2 gas were found to be 0% and 2847 rpm, respectively. - The concentration of N2O and optimum rotational speed of engine for HC werefound to be 12.71% and 3750 rpm, respectively. - The concentration of N2O and optimum rotational speed of engine for NOx werefound to be 0% and 4300 rpm, respectively

Frequency of waterpipe smoking and its effective factors among students of state universities in Kerman, Iran

Background — Nowadays, using tobacco such as waterpipe is considered a worldwide health problem. In recent years, the consumption of waterpipe, has been increased in different countries, especially among young people. This study was conducted to determine the frequency of waterpipe consumption and factors affecting it among Kerman students. Methods — This cross-sectional study was conducted among Kerman students. The students were selected using convenience sampling, and each of them completed the waterpipe consumption questionnaire. Data analysis was performed using chi-square test and logistic regression, as well as SPSS 17 software. Results — In this study, 675 students were investigated. The mean (±standard deviation) age of the subjects was 21.1 (±2.6) years and 39% of them were male, and 30% of students had the experience of waterpipe consumption. The most important reason for waterpipe was entertainment, followed by curiosity. The waterpipe consumption was correlated with male gender, lower education level, living in a single house, and its consumption by friends or family members. Conclusion — The results indicated that approximately one third of students experienced waterpipe smoking and some groups of them were susceptible to waterpipe smoking. Therefore, planning and intervention for the students are needed