Linear Precoding and Equalization for Network MIMO with Partial Cooperation

A cellular multiple-input multiple-output (MIMO) downlink system is studied in which each base station (BS) transmits to some of the users, so that each user receives its intended signal from a subset of the BSs. This scenario is referred to as network MIMO with partial cooperation, since only a subset of the BSs are able to coordinate their transmission towards any user. The focus of this paper is on the optimization of linear beamforming strategies at the BSs and at the users for network MIMO with partial cooperation. Individual power constraints at the BSs are enforced, along with constraints on the number of streams per user. It is first shown that the system is equivalent to a MIMO interference channel with generalized linear constraints (MIMO-IFC-GC). The problems of maximizing the sum-rate(SR) and minimizing the weighted sum mean square error (WSMSE) of the data estimates are non-convex, and suboptimal solutions with reasonable complexity need to be devised. Based on this, suboptimal techniques that aim at maximizing the sum-rate for the MIMO-IFC-GC are reviewed from recent literature and extended to the MIMO-IFC-GC where necessary. Novel designs that aim at minimizing the WSMSE are then proposed. Extensive numerical simulations are provided to compare the performance of the considered schemes for realistic cellular systems.Comment: 13 pages, 5 figures, published in IEEE Transactions on Vehicular Technology, June 201

Robust Joint Precoder and Equalizer Design in MIMO Communication Systems

We address joint design of robust precoder and equalizer in a MIMO communication system using the minimization of weighted sum of mean square errors. In addition to imperfect knowledge of channel state information, we also account for inaccurate awareness of interference plus noise covariance matrix and power shaping matrix. We follow the worst-case model for imperfect knowledge of these matrices. First, we derive the worst-case values of these matrices. Then, we transform the joint precoder and equalizer optimization problem into a convex scalar optimization problem. Further, the solution to this problem will be simplified to a depressed quartic equation, the closed-form expressions for roots of which are known. Finally, we propose an iterative algorithm to obtain the worst-case robust transceivers.Comment: 2 figures, 5 pages, conferenc

Evaluation of Evapotranspiration Rate and Water Productivity Based on FAO WaPOR Database in Qazvin Plain

Introduction Achieving food security in the future with sustainable use of water resources will be a big challenge for the current and future generations. Population increase, economic growth and climate change intensifythe pressure on existing resources. Agriculture is a key consumer of water, and it is necessary to closely monitor water productivity for it and explore opportunities to increase its productivity. Systematic monitoring of water productivity through the use of remote sensing techniques can help identifying the gaps in water productivity and evaluate appropriate solutions to address these gaps.   Materials and Methods Qazvin plain is known as a hub of modern agriculture by providing about 5% of the country's agricultural products. Therefore, estimating water demand and water productivity in agricultural management in the region is considered important and necessary. In order to monitor water productivity through access to various data across Africa and the Middle East, the WaPOR database provides the possibility to examine the rate of evapotranspiration, biomass and gross and net biomass volume productivity based on the land use map in the period of years 2009 to 2021. In this database, it is possible to check the mentioned items at three levels with different spatial resolution, which according to the scope of the study, it is possible to check values with a spatial resolution of 250(m). In order to determine the efficiency and accuracy of the land cover classification map of the WaPOR database, the results obtained are examined and compared with the Dynamic World model, which represents a global model with high accuracy. For this purpose, the latest land use map related to 2021 Using the WaPOR database and Dynamic World in the GEE system, it was prepared and based on the classification of the region in order to check the accuracy of the user map of the WaPOR database and to determine the percentage of each class compared to each other. Finally, all estimable indicators were calculated and checked by the WaPOR database during the years 2009 to 2022.   Results and Discussion The amount of evapotranspiration of the plants covered by the irrigation network in the period of 2009 to 2016 has been associated with a relatively stable trend, but this trend has decreased in 2017 onwards, which is one of the reasons for the decrease in the amount of evapotranspiration in this the period of time and can refer to the lack of water available to the plant due to the limited water resources in recent years. The investigation of the total amount of biomass in different lands shows that during the years 2009 to 2022, this index has been accompanied by a gradual increase in all uses, so that the amount of TBP index in 2020 was 17% more than in 2009. It shows the amount of biomass in different lands. The amount of biomass in the lands covered by the water network is 5 to 6 times higher than that of the rainfed lands. Among the influential parameters in estimating the TBP index, we can mention the amount of evaporation, transpiration, and transpiration, the increase or decrease of each of these parameters will have a significant impact on the estimated amount of biomass. The results showed that the amount of biomass production in the areas covered by the irrigation network largely depends on the high transpiration rate in these areas. From the beginning of 2009 to 2016, the gross amount of biomass water in the lands covered by the irrigation network has been accompanied by an increase, but in 2017, drastic changes in the process of underground changes will decrease the area of the lands covered by the network and many of these lands. It has been turned into fallow and rainfed lands. The analysis of NBWP index also showed that the amount of net productivity in rainfed lands is strongly dependent on the annual increase rate, and much of the crop yield in rainfed lands is dependent on the amount received. Among the influential parameters in estimating the total amount of biomass, we can mention the amount of evaporation, transpiration and transpiration, the increase or decrease of each of these parameters will have a significant impact on the amount of estimated biomass.   Conclusion WaPOR database data can play an important role in estimating the rate of delayed transpiration and parameters related to water productivity in the region due to its ten-day spatial resolution and the absence of data gaps. In general, the WaPOR database can be used as a guide in the reliable determination of evapotranspiration values and planning related to water resources in the agricultural sector

Meta-analysis of the effectiveness of distance education in higher Education learning-teaching activities

Background and Objective:Higher education has faced many challenges and issues during the last two decades, among which we can mention the following: inability to produce theoretical knowledge and use of basic and theoretical knowledge produced in other countries. Of the world, the inapplicability of university education, the lack of an inappropriate relationship between the university and other social sectors, neglecting research functions and services in universities, the problem of multiple decision centers and the existence of multiple trustees on the one hand, and the excalating growth of students and applicants to universities and institutions of higher education, the slight expansion of the higher education system regardless of the existing capacity and economic, social and cultural capacity of the community to accept university graduates, reduced financial resources and pressure from society For responsibility and accountability on the other hand; the higher education system needs to maintain and improve the quality of higher education to meet these challenges. To succeed in this, all the functions of higher education in general must be considered comprehensively. In this regard, one of the measures that higher education deliberates to answer its problems was technology-based education, including distance education and distance learning. Considering the contradiction in the findings of the studies conducted on the effectiveness of distance education methods, the present study was conducted to evaluate the effectiveness of distance education in higher education. Methods: The research method is based on secondary analysis and meta-analysis. The statistical population consists of all quasi-experimental studies which have already been conducted on the effectiveness of various types of distance education in higher education in Iran. The whole census was used for sampling. According to the inclusion and exclusion criteria, 79 studies were identified as the sample size.To collect the data, a researcher-made worksheet was employed in three sections: bibliographicaldata, methodological data, and findings. To analyze the data, the effect size index and the homogeneity test were performed using CMA-Version 2.0 statistical software. Findings:The research findings indicated that all of distance education methods in higher education of Iran were effective, but this effectiveness was moderate (ES =0.526, P <0.01); the area under the normal curve, the average implementation of distance education is 69% more effective than traditional methods. In addition, the meta-regression of the effect of year on the results of research showed that with an increase in the implementation of distance education methods, .07%was added to the effectiveness of these methods. In other words, the implementation of distance education methods in higher education will become more effective over time. Conclusion: Considering that the study of moderating variables was not one of the objectives of this study, it is recommended that in future research, the impact of these components on the results of the study be examined to determine the impact of these components to explain and control the results.   ===================================================================================== COPYRIGHTS  ©2019 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

Sum rate maximization of MIMO broadcast channels with coordination of base stations

Abstract-We consider cooperative downlink transmission in multiuser, multi-cell and multiple-antenna cellular networks. Recently, it has been shown that multi-base coordinated transmission has significant spectral efficiency gains over that without coordination. The capacity limits can be achieved using a non-linear precoding technique known as dirty paper coding, which is still infeasible to implement in practice. This motivates investigation of a simpler linear precoding technique based on generalized zero-forcing known as block diagonalization (BD). In this paper, an enhanced form of BD is proposed for multiple-input multiple-output (MIMO) multi-base coordinated network. It involves optimizing the precoding over the entire null space of other users&apos; transmissions. The performance limits of the multiple-antenna downlink with multi-base coordination are studied using duality of MIMO broadcast channels (BC) and MIMO multiple-access channels (MAC) under per-antenna power constraint, which has been established recently

The southern Zagros collisional orogen: new insights from transdimensional‐trees inversion of seismic noise

Imaging and resolving the lateral continuity of 3‐D crustal structures enhances our ability to interpret seismicity, and to understand how orogens are created. We apply a Bayesian, hierarchical inversion approach based on a transdimensional trees‐structured wavelet parameterisation to recover phase‐velocity maps at 2‐40 second periods. We then invert phase‐velocity dispersion to constrain a 3‐D shear‐velocity model of the crust beneath south‐central Iran. Together with accurate earthquake centroid depths and focal mechanisms, the pattern of 3‐D velocity variations supports recent suggestions that most large earthquakes in the Zagros occur within the lower sedimentary cover, or close to the sediment‐basement interface. Furthermore, we find evidence for Arabian basement underthrusting beneath central Iran, although only in one location does it appear to generate earthquakes. Our new 3‐D tomographic model clarifies and throws new light on the crustal structure of the SE Zagros and its relation to seismicity and active faulting

Effect of Glucose, Fructose, and Sucrose on Vase Life, Antioxidants Enzymes, and Some Physiologic Parameters of Carnation cv. ‘Yellow Candy’ Cut Flower

Introduction  Carnation (Dianthus caryphyllus L.), from Caryophyllaceae family, is one of the most important cut flowers in the world that its short vase life reduces the economic value. Postharvest longevity of cut flowers can be prolonged using carbohydrates (sugars) in a vase jar. Cut flowers undergo some physiological and biochemical changes that often lead to an early senescence. To delay the aging process in cut flowers, it is necessary to evaluate many aspects of preparation for storage conditions, especially preservative solutions that affect the quality and longevity of these flowers. Many flowers are harvested before they are fully developed, to ensure a long postharvest life and to minimize mechanical damages that might occur during handling. The growth and development of flower buds on cut flowers require food (especially carbohydrates), which is stored in the leaves and stems. These stored carbohydrates can be mobilized for the flower bud to use but maybe they are insufficient when the buds are harvested at a tight-bud stage. To maintain metabolic activities, including respiration, even for cut flowers that have reached full development, it is necessary to provide adequate reserves to achieve acceptable postharvest life. When stored materials are low, leaves and flowers age faster and the petals fade. Under these conditions, supplements can be provided to the flowers by adding sugars such as glucose, fructose and sucrose to the vase solutions. However, it is important to note that a sugar solution is also suitable for the growth of microorganisms, so that an antimicrobial agent should be added to the vase solution as well. Many researches were carried out on prolonging the vase life of cut carnation flowers with different preservative solutions together with an antimicrobial agent. Studies on postharvest longevity of cut carnation flowers using sugars as preservative solutions is low. Therefore, the aim of the present study was to evaluate the effect of sugars (glucose, fructose and sucrose) and application time on vase life and some physiological parameters of carnation cv. ‘Yellow Candy’ cut flowers. Materials and Methods  A factorial experiment based on completely randomized design in three replicates was performed in order to investigate the effect of different levels (0, 50 and 100 g/L) of three types of sugars (glucose, fructose, and sucrose) and two sugar application times (the first and second 24 h, on 2019) on vase life of carnation cv. ‘Yellow Candy’ cut flowers. Some other traits such as water uptake, dry mater, relative fresh weight, protein and carotenoid of petal, leaf chlorophyll, POD and SOD enzymes activity and MDA were also measured. The statistical analysis of data was performed using Statistical Package for Social Sciences (SPSS) v 16.0. Least significant difference (LSD) test at P < 0.05 was used to find out the significance of differences among the mean values.     Results and Discussion Results showed that the effect of different levels of sugars on all evaluated traits was significant. Each three levels of sugars at each two applied times caused to increase vase life and relative traits. Maximum vase life (18 days) was obtained in 50 g/L glucose at the first 24 h with no statistically significant differences with the 100 g/L sucrose and fructose at the first 24 h. The highest water uptakes and dry matter, the lowest POD and SOD activity and minimum MDA were obtained in treatment of 50 g/L glucose at the first 24 h. The study found that the highest levels of petal protein content, chlorophyll a, b, and total chlorophyll were achieved in carnation "Yellow Candy" cut flowers treated with 50 g/L glucose after 24 hours of harvesting. The application of sugars at the first 24 hours after harvesting had a greater impact on improving the vase life of the flowers compared to the second 24 hours. Therefore, the use of glucose as an external holding solution, preferably within the early hours of harvesting, is recommended to prolong the postharvest life of carnation "Yellow Candy" cut flowers. The study also revealed that the use of external holding solutions, particularly sugars combined with antimicrobial agents, can have a positive effect on prolonging the vase life of cut flowers. The concentration of sugar required in the holding solution varies depending on the type of flower being treated, with most flowers requiring a concentration of 2% sugar. However, some flowers may require higher concentrations, up to 4-6%, while others may be damaged if treated with concentrations higher than 1%. The application of sucrose has been shown to increase glucose and fructose levels in petals, further supporting the use of external holding solutions containing sugars for extending the vase life of cut flowers. Therefore, it is important to examine each flower before treating it to determine the optimal concentration of sugars. Sugars are a source of energy and carbon for cut flowers and play an important role in decreasing the protein degradation and ethylene production, maintenance of osmotic balance, increasing water uptake, and finally delaying in senescence proces