Equality of ordinary and symbolic powers of Stanley-Reisner ideals

This paper studies properties of simplicial complexes for which the m-th symbolic power of the Stanley-Reisner ideal equals to the m-th ordinary power for a given m > 1. The main results are combinatorial characterizations of such complexes in the two-dimensional case. It turns out that there exist only a finite number of complexes with this property and that these complexes can be described completely. As a consequence we are able to determine all complexes for which the m-th ordinary power of the Stanley-Reisner ideal is Cohen-Macaulay for a given m > 1.Comment: 19 page

Deep Learning-Aided Multicarrier Systems

This paper proposes a deep learning (DL)-aided multicarrier (MC) system operating on fading channels, where both modulation and demodulation blocks are modeled by deep neural networks (DNNs), regarded as the encoder and decoder of an autoencoder (AE) architecture, respectively. Unlike existing AE-based systems, which incorporate domain knowledge of a channel equalizer to suppress the effects of wireless channels, the proposed scheme, termed as MC-AE, directly feeds the decoder with the channel state information and received signal, which are then processed in a fully data-driven manner. This new approach enables MC-AE to jointly learn the encoder and decoder to optimize the diversity and coding gains over fading channels. In particular, the block error rate of MC-AE is analyzed to show its higher performance gains than existing hand-crafted baselines, such as various recent index modulation-based MC schemes. We then extend MC-AE to multiuser scenarios, wherein the resultant system is termed as MU-MC-AE. Accordingly, two novel DNN structures for uplink and downlink MU-MC-AE transmissions are proposed, along with a novel cost function that ensures a fast training convergence and fairness among users. Finally, simulation results are provided to show the superiority of the proposed DL-based schemes over current baselines, in terms of both the error performance and receiver complexity

Effect of Creep and Shrinkage model in calculation of long-term deflection of three-span solid slab continuous prestressed concrete bridge

Shrinkage and creep effect significantly to the long-term deflection of prestressed concrete bridge. The proper shrinkage and creep models should be developed to meet the requirements of deflection effect calculation. There are many models has been researched and developed. Each specification, such as ASSHTO, Eurocode, ACI and CEB-FIB, has their own model of shrinkage and creep by considering different input parameter. The long-term deflection calculation is also different in each specification as a result. In this paper, several shrinkage and creep models were selected and reviewed to see the difference and compare by using popular concrete grade in Vietnamese bridge building     (C40 and C45, equivalent to 40 and 45 Mpa, respectively). Those selected shrinkage and creep models are applied in calculation of deflection for a typical three-span continuous solid slab prestressed concrete bridge. The calculation result show the significant different of long-term deflection and the ASSHTO shrinkage and creep model show the biggest deflection

Effect of Creep and Shrinkage model in calculation of long-term deflection of three-span solid slab continuous prestressed concrete bridge

Shrinkage and creep effect significantly to the long-term deflection of prestressed concrete bridge. The proper shrinkage and creep models should be developed to meet the requirements of deflection effect calculation. There are many models has been researched and developed. Each specification, such as ASSHTO, Eurocode, ACI and CEB-FIB, has their own model of shrinkage and creep by considering different input parameter. The long-term deflection calculation is also different in each specification as a result. In this paper, several shrinkage and creep models were selected and reviewed to see the difference and compare by using popular concrete grade in Vietnamese bridge building     (C40 and C45, equivalent to 40 and 45 Mpa, respectively). Those selected shrinkage and creep models are applied in calculation of deflection for a typical three-span continuous solid slab prestressed concrete bridge. The calculation result show the significant different of long-term deflection and the ASSHTO shrinkage and creep model show the biggest deflection

Management and monitoring of air and water pollution by using GIS technology: Research article

The need for a green clean living environment is increasing today, with the boom of the socioeconomic development, educational level. However, the environmental pollution becomes an alerted global issue due to the large amount of wastes discharged making this need to be not easily met at the moment. Greenhouse gas emission mainly from energy, transport and agricultural land use is causing climate change because of their long atmospheric lifetime and trapping the heat in the atmosphere. Harmful effects and damages caused by environment pollution and climate change are unpredictable. It was reported that every year millions of people die because of fine particles when exposing to air pollution and other millions die from water-born diseases. Management and monitoring of air and water pollution by using GIS technology is an effective method. The measured data can be obtained continuously, quickly and accurately at stations in any regions even with complex terrain. This helps reduce the required number of employees, manage automatically and continuously a large number of data.Ngày nay nhu cầu về một môi trường sống xanh, sạch đang gia tăng, với sự bùng nổ của phát triển kinh tế - xã hội và trình độ dân trí. Tuy nhiên, ô nhiễm môi trường đang trở thành một vấn đề cảnh báo toàn cầu do số lượng lớn các chất thải được xả ra môi trường làm cho nhu cầu này không dễ dàng được đáp ứng tại thời điểm này. Phát thải khí nhà kính chủ yếu là từ sử dụng năng lượng, giao thông vận tải và đất nông nghiệp đang gây ra biến đổi khí hậu vì thời gian tồn tại của cúng dài và giữ nhiệt trong khí quyển. Các ảnh hưởng xấu và thiệt hại gây ra bởi ô nhiễm môi trường và biến đổi khí hậu là không thể đoán trước. Thông tin báo cáo chỉ ra rằng mỗi năm có hàng triệu người chết vì hít các hạt bụi mịn khi tiếp xúc với ô nhiễm không khí; và hàng triệu người khác chết vì bệnh do nước sinh ra. Quản lý và giám sát ô nhiễm không khí và nước bằng cách sử dụng công nghệ GIS là một phương pháp hiệu quả. Các dữ liệu đo có thể được lấy liên tục, nhanh chóng và chính xác tại các trạm ở bất kể khu vực nào, ngay cả nơi có địa hình phức tạp. Điều này giúp làm giảm số lượng lao động cần thiết, quản lý tự động và liên tục một số lượng lớn dữ liệu

Short- and medium-term car registration forecasting based on selected macro and socio-economic indicators in European countries

The automotive industry plays a key role in the European economy. In this paper, we determine which macro and socio-economic indicators have significant predictive power on car registrations - a proxy to automotive sector performance - across European countries. Contrary to the current literature which mainly focuses on long-term forecasting, we built our models on the highly seasonal monthly data of a medium-term period to make short-term forecasts. Our approach utilises predictors identified by the literature review. Presented models are built on the Vector Autoregressive models and are accompanied by formal tests, such as the Granger causality test. We have found mixed evidence about the importance of selected predictors as no general patterns were identified. We have found that the most useful predictor is the total number of registrations from the strongest export partner and past registration figures in the analysed country. Car registrations are virtually inelastic to the change of public transportation costs, fuel prices and short-term interest rates offered to households in most of the analysed countries. We have received mixed results about household sentiment across countries. Countries with a higher level of GDP are more sensitive to the changes in unemployment. © 2019 Elsevier LtdCzech Science FoundationGrant Agency of the Czech Republic [16-25536S

Research of Soil Moisture Retrieval Algorithms for Processing Radiometry Data

Since 2012, the experts of Space Technology Institute  have carried out the field experiments to obtain a high-resolution dataset  of microwave radiometers for land surface parameters (soil moisture, soil  temperature, vegetation water content), in order to improve the soil  moisture retrieval methodology. L-band radiometers were used for measuring  the brightness temperature of the bare soil. Field experiments for passive  microwave remote sensing of soil moisture were carried out in Hoai Duc  District in 2012. L-band microwave radiometers were used for measuring the  microwave emission of bare agricultural fields. The radiometers, which are  used for soil moisture measurement, worked well during the experimental  campaign and produced volumetric soil moisture estimates that compared well  with the ground-truth measurements. Explanations for the observed  discrepancies are presented. The experimental results showed that the model  of Choudhury et al. for surface roughness correction provides a better fit  to radiometric data over the angular range between 20° and 50° for  $n = 0$ (i.e., the $\cos ^{2}\theta$  factor in the exponential in (15) is suppressed).  Based on the results of the experiments conducted over two experimental  sites with different soils, namely sandy loam at Hoai Duc Agrometeorologyl  Center, it may be concluded that the testing of both the radiometric  equipment and the method for soil moisture retrieval was very successful,  and the main goal of the experiments was fulfilled

LƯỢNG GIÁ KINH TẾ GIÁ TRỊ DU LỊCH TỪ CÁC HỆ SINH THÁI BIỂN VÙNG ĐẢO BẠCH LONG VĨ, HẢI PHÒNG

Bach Long Vi island is an offshore district in the centre of the Gulf of Tonkin in Vietnam and administratively belongs to Hai Phong city. The island surrounded by abundant marine ecosystems with high biodiversity is one of 16 marine protected areas approved by the Prime Minister of Vietnam on 26/5/2010 according to the Decision No.742/QD-TTg. Currently, in addition to the main service of economic activities as fishery logistics, Bach Long Vi island still remains the wild features with beautiful scenery, fresh air and the diversity of marine species that are suitable for the development of eco-tourism and resorts. Although tourism at present is not developed yet, its potentials are promising. Deploying zone travel cost method (ZTCM), tourism potentials based on ecosystem services of Bach Long Vi island were estimated at 5.4 billion VND (Vietnamese currency). The value can be much higher if the infrastructure of the island is improved and the island is accessible more easily. Tourism potential valuation and identification of the advantages of the island strongly support tourism planning in the future.Đảo Bạch Long Vĩ là đảo xa bờ nhất của Việt Nam trong vịnh Bắc Bộ và về mặt hành chính là một huyện đảo trực thuộc thành phố Hải Phòng. Đảo có hệ sinh thái biển bao quanh khá phong phú, đa dạng sinh học cao, là một trong số 16 khu bảo tồn thiên nhiên biển Việt Nam đã được Thủ tướng chính phủ phê duyệt lựa chọn vào ngày 26/5/2010 theo Quyết định số 742/QĐ-TTg. Hiện nay, ngoài hoạt động kinh tế dịch vụ chính là hậu cần nghề cá, huyện đảo Bạch Long Vĩ vẫn giữ nguyên được nét hoang sơ với cảnh quan đẹp, không khí trong lành và sự đa dạng của các loài hải sản thích hợp với phát triển du lịch sinh thái, nghỉ dưỡng. Mặc dù hiện tại du lịch chưa phát triển ở vùng đảo, tuy nhiên tiềm năng du lịch rất lớn. Bằng phương pháp tính chi phí du lịch theo vùng (ZTCM), giá trị tiềm năng du lịch trên nền tảng các dịch vụ hệ sinh thái của đảo Bạch Long Vĩ được ước tính là 5,4 tỷ đồng/năm. Giá trị này còn cao hơn nhiều nếu hạ tầng cơ sở của đảo và khả năng đi lại thuận tiện. Ước tính giá trị tiềm năng du lịch và xác định cụ thể những yếu tố thuận lợi giúp khu vực này phát triển tốt du lịch trong tương lai