Climate change has altered hydrologic conditions, which directly affects water resources. In addition, increasing human activities have an impact on water resources, water environment and water ecology. Rivers are important channels of water cycle, the main source of fresh water for human consumption and an important renewed resource, which play essential roles in material cycle, energy flow and climate regulation. Reservoirs are important components of water conservancy constructions, and play vital roles in regional flood interception, water storage, and the regulation of water flow. It is of great significance to study the mechanism of the water cycle under the changing environment and build an optimized water resource management based on it.Rivers and reservoirs are faced with many problems, and it is necessary to study the optimal management of water resources in rivers, lakes and reservoirs, the hydrological mechanism and ecological environment process (including experimental and numerical simulation methods), the optimal operation of engineering facilities and their natural and social effects, as well as the mitigation of water security problems and ensuring the sustainability of the ecosystem through the integrated management of rivers and reservoirs.In Focus–a book series that showcases the latest accomplishments in water research. Each book focuses on a specialist area with papers from top experts in the field. It aims to be a vehicle for in-depth understanding and inspire further conversations in the sector.
Reactive jamming is considered the most powerful jamming attack as the attack efficiency is maximized while the risk of being detected is minimized. Currently, there are no effective anti-jamming solutions to secure OFDM wireless communications under reactive jamming attack. On the other hand, MIMO has emerged as a technology of great research interest in recent years mostly due to its capacity gain. In this paper, we explore the use of MIMO technology for jamming resilient OFDM communication, especially its capability to communicate against the powerful reactive jammer. We first investigate the jamming strategies and their impacts on the OFDM-MIMO receivers. We then present a MIMO-based anti-jamming scheme that exploits interference cancellation and transmit precoding capabilities of MIMO technology to turn a jammed non-connectivity scenario into an operational network. Our testbed evaluation shows the destructive power of reactive jamming attack, and also validates the efficacy and efficiency of our defense mechanisms.
With the development of wireless communication technology, the utilization of the ambient information that the network users observe has attracted much attention. In this paper, we focus especially on the utilization of observed environmental signals for authentication systems. Ambient information taken as unique data at a particular time and place can be utilized to construct stronger authentication systems. However, since the environmental condition of the network is different for each location, which has a huge effect on the observed ambient information in the area, required data are also different for each place. Thus, in this paper, we propose an efficient data collection method which dynamically changes the way data is collected according to the requirements and the network condition. More specifically, our proposal aims to collect uniform amount of fresh data from areas with varying population density. Additionally, an algorithm to improve the efficiency of our proposal regarding the accommodation of the environmental condition of the network is introduced. Moreover, numerical results verify the effectiveness of our proposal.
Passive monitoring by distributed wireless sniffers has been used to strategically capture the network traffic, as the basis of automatic network diagnosis. However, the traditional monitoring techniques fall short in cognitive radio networks (CRNs) due to the much larger number of channels to be monitored, and the secondary users' channel availability uncertainty imposed by primary user activities. To better serve CRNs, we propose a systematic passive monitoring framework for traffic collection using a limited number of sniffers in WiFi like CRNs. We jointly consider primary user activity and secondary user channel access pattern to optimize the traffic capturing strategy. In particular, we exploit a non-parametric density estimation method to learn and predict secondary users' access pattern in an online fashion, which rapidly adapts to the users' dynamic behaviors and supports accurate estimation of merged access patterns from multiple users. We also design near-optimal monitoring algorithms that maximize two levels of quality-of-monitoring goals respectively, based on the predicted channel access patterns. The simulations and experiments show that our proposed framework outperforms the existing schemes significantly.
In the property management system in common use at present,the data dealt with are only some data of routine property,but to modern intelligent building,various kinds of systems included of its inside are many,and utilize the management system of routine property to collect,deal with the data with close and relevant every equipment storey and estate management in the building at this moment,seem powerless.In order to change this kind of state,combine the concrete application of the internet configuration(WebAccess) technology in the intelligent building property management system(IPMS),and provides the concrete application model for discussing how to solve above-mentioned problems.
The paper discusses the structure,content and characteristics of information architecture,points out the complexity of information architecture and introduces indexes of information architecture evaluation,and conducts a probe study of evaluation methods of information architecture.
Information technology (IT) has increasingly been highlighted in the construction industry as an integral contributor in improving project performance and competition. IT application challenges for infrastructure operation companies still exist creating a need for improved evaluation methods of information systems (IS) prior to application. This study proposes a scheme for evaluating IS from both functional and nonfunctional aspects at the maintenance management process level. Considering the characteristics of maintenance management processes, discrete-event simulation coupled with the Keystroke-Level Model is adopted in the scheme. A case study is conducted using the scheme, and results reveal that IS is positively associated with maintenance performance. The effects of IS of varying levels on different processes and users are determined based on the functions within the organization. Moreover, the obstacles that hinder favorable user experiences of IS are identified. The case study verifies that the effects of IS on maintenance performance can be assessed quantitatively and objectively through application of the scheme. Decision makers may apply the scheme in the IS planning phase or in optimizing the available IS.
In view of the traditional intrusion prevention system is connected in series mode in the network, the ability of dealing with the intrusion is limited, and it will cause network congestion easily, especially in the cloud computer environment. Aiming at the problems mentioned above, a scheme for the cloud platform intrusion prevention is proposed in the paper, based on the construction of the software defined network. By using the programmable feature of the SDN, the IPS in the scheme will transmit the intrusion information to the controller, when the intrusion detection system detects intrusion. Then the controller will send security policy to virtual switch, so that it can filter the intrusion traffic and achieve the purpose of blocking intrusion behavior dynamically. A comparative analysis between the proposed scheme and transitional IPS is made through the experiment, the result shows that the efficiency of the intrusion detection in the new scheme can be improved by two times compared with the traditional intrusion prevention scheme. So, it has certain reference significance for the deployment of intrusion prevention scheme in cloud environment.
With the development of computer and information technology, computer and network have been popular. At the same time, security problem has greatly aroused people's attention, especially in campus environment. Campus network as an important part of the campus life, people also arouse enough attention to the problems of personal computer safety management. Running a set of effective campus network monitoring software is real needed for the campus network management and maintenance personal safety. In order to ensure the safety, reliability and steady running of the campus network, according to the present situation and development of the campus network, people plan and design to use network monitoring system on the campus network security management. The system can effectively control and manage the reliable operation of the campus network.
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