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Water shortage for agriculture gets more and more severity which makes it necessary to develop water saving agriculture and achieving the leaf water potential accurately is the key. To ensure the accuracy of the plants' microenvironment information is the most important. Achieving the ideal microenvironment data under closed environment first, and then mixed with various types of outliers manually...
The boundary node chain of a wireless network with arbitrary deployment, recognized through method based on local generalized convex hull (Igch) or local convex view (lcv), often has gaps, especially where notches or holes exist. The existence of these gaps may cause serious unexpected problems in some wireless network applications. When using Igch to recognize the boundary of a network, a smaller...
More than an adaptive system, the cognitive radio system should be a kind of intelligent system. In the paper, a Q-learning algorithm of the intelligent control theory is adopted to solve the sensing task selection problem among cognitive radio users in the distributed cognitive radio networks. In the proposed scheme, each cognitive radio user selects its sensing task through times of interaction...
In this paper, we develop a distributed cooperative spectrum sensing algorithm based on network code to decrease the need for bandwidth in cognitive radios. The model of the distributed cooperative spectrum sensing is analyzed, and the algorithm of distributed scheme based on network code is described. The simulation results show that compared with the distributed scheme without network code and the...
Spectrum sensing is the key enabling technology for cognitive radio networks. The main objective of the spectrum sensing is to provide more spectrum access opportunities to cognitive radio (CR) users without interfering with the licensed users. In this paper, we propose a half-voting based twice-cooperative spectrum sensing scheme. Simulation results show that the proposed sensing method can achieve...
Sensing coverage is defined as the ratio of the sensible area to the entire desired area. It is one of the critical measures of performance or service quality offered by a sensor network. In previous studies, the sensing range of a node is generally assumed to be a deterministic value in all directions. In realistic environments, the sensing range of a node is not a constant because of shadowing effects...
Spectrum sensing is a key technology in cognitive radio (CR) and cooperative spectrum sensing is derived due to the effects of channel fading. In this paper, we focus on the optimal number of secondary users in cooperative spectrum sensing to maximize the utility in CR network. By considering both the detection error probability and the resource used by the secondary users in cooperation, we derive...
Cooperative spectrum sensing enables a Cognitive Radio (CR) networks to reliably detect primary users and avoid causing interference to primary user's communications, and data fusion technique is a key component of it. However, when the number of CR users tends to be large, the bandwidth for reporting their sensing results to the fusion center will be very enormous. In this paper, censoring schemes...
AIS (Automatic Identification System), a new type of Navaid at sea, is one of the key equipment to navigation for a ship as same as radar. But, there are many differences between them in the performance. It is very important to fuse the target information from the two sensors to get mutual benefits. The paper studies on the association arithmetic of the targets from the two sensors by adopting T_D...
In the embedded distribution control system, the analogue quantity under test is usually nonlinear. In order to realize fast and accurate detection of it we present a multipoint calibration, which includes two program editing thoughts: subsection linearization and subsection variable slope.
Spectrum sensing is a critical phase in building a cognitive radio network. However, when the number of cognitive user is very large, the bandwidth for reporting cognitive users' sensing results will be insufficient. In this paper, we propose a new cooperative spectrum sensing algorithm to alleviate the bandwidth problem of reporting channel. Compared with conventional method, only the cognitive users...
Energy efficiency is a critical consideration in the design of low cost sensor networks. This paper studies the problem of extending the lifetime of the sensor networks as far as possible while maintaining the quality of network coverage. A systematical analysis on the relationship between the network lifetime and cover sets alternation is given, and by introducing the concept of time weight factor,...
In this paper, a new self-repairing control system (SRCS) is developed for nonlinearly-perturbed plants with sensor failures of a stuck-type. The SRCS can automatically replace the faulty sensor with the healthy one if the failure occurs. Under the diverging condition, only a detector of the first order and an auxiliary signal are utilized to detect the failure exactly. Hence, no information about...
In this paper we present dynamics of an inertial measurement unit (IMU) in for educational use. Students will learn how to use mathematical expressions on kinematics and dynamics, with use of a simulator and a small scale test site. Combining the simulator and the test site will bring the theoretical expression out with a practical side. The main part of this paper is focused on how to use the sensors...
In wireless sensor networks, density control is an important technique for prolonging a network's lifetime. To reduce the overall energy consumption, it is desirable to minimize the overlapping sensing area of sensor nodes. In this paper, we study the problem of energy-efficient area coverage by the regular placement of sensors with adjustable sensing and communication ranges. We suggest a more accurate...
In this paper, designing channel sensing policies for cognitive radio networks is discussed. A discrete-time semi- Markov channel model is first introduced, which facilitates the analysis on more general channel occupancy behaviors and possible asynchronism among primary and secondary users. Based on the characteristics of the channels at the stationary state, multiple channel sensing policies have...
This paper presents queueing analysis of opportunistic access in cognitive radios. The primary (licensed user) has priority over the secondary user and it does not need to care about the secondary user transmissions. A time slotted system is assumed, so that the secondary user can perform spectrum sensing at the beginning of the slot to know if it is occupied by primary or not. If the slot is free,...
An improved direction-of-arrivals (DOAs) estimation via phase information of sparse solution is presented in this paper. Unlike the conventional sparse source localization approach using the amplitude of sparse solutions only, through a special partition of the receiving data of the sensors, the phase information of the available sparse solutions is also extracted to estimate DOAs. For the true DOAs...
Traffic congestion avoidance is a critical issue associated with data routing in Wireless Sensor Networks (WSNs). Previous researches employ either traffic or resource control strategies as solutions. In this paper, we propose an energy-efficient grid-based traffic congestion avoidance scheme in WSNs, termed as TALONet. With our mechanism, the approaches applied to avoid congestion have three folds:...
In cognitive radio systems, as the sensing ability of single cognitive user is limited, the opportunistic spectrum access has to allow different cognitive users to cooperatively search for and exploit instantaneous spectrum availability. In this paper, we address the design of opportunistic spectrum access for cognitive radio system employing cooperative spectrum sensing. The opportunistic spectrum...
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