Coverage is an important issue in the area of wireless sensor networks, which reflects the monitoring quality of the sensor networks in scenes. Most sensor coverage research focuses on the ideal two-dimensional （2-D...Coverage is an important issue in the area of wireless sensor networks, which reflects the monitoring quality of the sensor networks in scenes. Most sensor coverage research focuses on the ideal two-dimensional （2-D） plane and full three-dimensional （3-D） space. However, in many real-world applications, the target field is a 3-D complex surface, which makes conventional methods unsuitable. In this paper, we study the coverage problem in directional sensor networks for complex 3-D terrains, and design a new surface coverage algorithm. Based on a 3-D directional sensing model of nodes, this algorithm employs grid division, simulated annealing, and local optimum ideas to improve the area coverage ratio by optimizing the position coordinates and the deviation angles of the nodes, which results in coverage enhancement for complex 3-D terrains. We also conduct extensive simulations to evaluate the performance of our algorithms.展开更多
With the increasing demand for security,building strong barrier coverage in directional sensor networks is important for effectively detecting un-authorized intrusions.In this paper,we propose an efficient scheme to f...With the increasing demand for security,building strong barrier coverage in directional sensor networks is important for effectively detecting un-authorized intrusions.In this paper,we propose an efficient scheme to form the strong barrier coverage by adding the mobile nodes one by one into the barrier.We first present the concept of target circle which determines the appropriate residence region and working direction of any candidate node to be added.Then we select the optimal relay sensor to be added into the current barrier based on its input-output ratio(barrier weight)which reflects the extension of barrier coverage.This strategy looses the demand of minimal required sensor nodes(maximal gain of each sensor)or maximal lifetime of one single barrier,leading to an augmentation of sensors to be used.Numerical simulation results show that,compared with the available schemes,the proposed method significantly reduces the minimal deploy density required to establish k-barrier,and increases the total service lifetime with a high deploy efficiency.展开更多
In most areas of China, affected by the environment of low temperature and high humidity, the wind speed sensor and wind direction sensor are frozen and cannot output data in autumn, winter or the alternation of winte...In most areas of China, affected by the environment of low temperature and high humidity, the wind speed sensor and wind direction sensor are frozen and cannot output data in autumn, winter or the alternation of winter and spring. In order to solve the freezing situation of the wind sensor, this paper designs a new type of antifreeze wind speed sensor. After meteorology performance testing and field observation tests, the correlation coefficient of the observation data is demonstrated, and the data curve is fitted. The result shows the sensor is stable, and has a good antifreeze effect, the data output is reliable.展开更多
Direct current triboelectric nanogenerators(DC-TENGs)are a groundbreaking technology to capture micromechanical energy from the natural environment,which is crucial for directly powering sensor networks.However,the re...Direct current triboelectric nanogenerators(DC-TENGs)are a groundbreaking technology to capture micromechanical energy from the natural environment,which is crucial for directly powering sensor networks.However,the research bottleneck in enhancing the triboelectric electrification capability and charge storage capability of dielectrics has hindered the overall performance breakthroughs of the DC-TENG.Here,a field emission model-based DC-TENG(FEM-TENG)is proposed,inspired by lightning rods.The enhanced local electric field between dielectric materials and electrodes induces strong electron tunneling,which improves charge neutralization on the surface of materials and their internal charge storage space,thereby utilizing the dielectric volume effect effectively and strengthening triboelectricity.Guided by the field emission model,the FEM-TENG with a historic crest factor of 1.00375 achieves a groundbreaking record of an average power density of 16.061 W m^(-2)Hz^(-1)(1,591 W m^(-3)Hz^(-1)),which is 5.36-fold of the latest DC-TENG.In particular,the FEM-TENG with high durability(100%)truly realizes the collection of breeze energy and continuously drives 50 thermohygrometers.Four additional applications exemplify the FEM-TENG,enabling comprehensive sensing of land,water,and air.This work proposes a paradigm strategy for the in-depth utilization of dielectric films,aiming to enhance the output power of DC-TENGs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61373137,61572260,61373017,61373139,and 61572261)the Major Program of Jiangsu Higher Education Institutions(No.14KJA520002)Scientific&Technological Support Project of Jiangsu(No.BE2015702)
文摘Coverage is an important issue in the area of wireless sensor networks, which reflects the monitoring quality of the sensor networks in scenes. Most sensor coverage research focuses on the ideal two-dimensional （2-D） plane and full three-dimensional （3-D） space. However, in many real-world applications, the target field is a 3-D complex surface, which makes conventional methods unsuitable. In this paper, we study the coverage problem in directional sensor networks for complex 3-D terrains, and design a new surface coverage algorithm. Based on a 3-D directional sensing model of nodes, this algorithm employs grid division, simulated annealing, and local optimum ideas to improve the area coverage ratio by optimizing the position coordinates and the deviation angles of the nodes, which results in coverage enhancement for complex 3-D terrains. We also conduct extensive simulations to evaluate the performance of our algorithms.
基金This research was supported in part by the National Natural Science Foundation of China under Grant Nos.11405145,40241461,61374152,and 61876168Zhejiang Provincial Natural Science Foundation of China under Grant Nos.LY20F020024 and LY17F030016.
文摘With the increasing demand for security,building strong barrier coverage in directional sensor networks is important for effectively detecting un-authorized intrusions.In this paper,we propose an efficient scheme to form the strong barrier coverage by adding the mobile nodes one by one into the barrier.We first present the concept of target circle which determines the appropriate residence region and working direction of any candidate node to be added.Then we select the optimal relay sensor to be added into the current barrier based on its input-output ratio(barrier weight)which reflects the extension of barrier coverage.This strategy looses the demand of minimal required sensor nodes(maximal gain of each sensor)or maximal lifetime of one single barrier,leading to an augmentation of sensors to be used.Numerical simulation results show that,compared with the available schemes,the proposed method significantly reduces the minimal deploy density required to establish k-barrier,and increases the total service lifetime with a high deploy efficiency.
文摘In most areas of China, affected by the environment of low temperature and high humidity, the wind speed sensor and wind direction sensor are frozen and cannot output data in autumn, winter or the alternation of winter and spring. In order to solve the freezing situation of the wind sensor, this paper designs a new type of antifreeze wind speed sensor. After meteorology performance testing and field observation tests, the correlation coefficient of the observation data is demonstrated, and the data curve is fitted. The result shows the sensor is stable, and has a good antifreeze effect, the data output is reliable.
基金supported by the National Natural Science Foundation ofChina(NSFC)(52272191)the National Key R&D Project from Minister of Science and Technology(2021YFA1201602)the Fundamental Research Funds for the Central Universities(grantno.2021CDJQY-005,2022CCJJCLK001).
文摘Direct current triboelectric nanogenerators(DC-TENGs)are a groundbreaking technology to capture micromechanical energy from the natural environment,which is crucial for directly powering sensor networks.However,the research bottleneck in enhancing the triboelectric electrification capability and charge storage capability of dielectrics has hindered the overall performance breakthroughs of the DC-TENG.Here,a field emission model-based DC-TENG(FEM-TENG)is proposed,inspired by lightning rods.The enhanced local electric field between dielectric materials and electrodes induces strong electron tunneling,which improves charge neutralization on the surface of materials and their internal charge storage space,thereby utilizing the dielectric volume effect effectively and strengthening triboelectricity.Guided by the field emission model,the FEM-TENG with a historic crest factor of 1.00375 achieves a groundbreaking record of an average power density of 16.061 W m^(-2)Hz^(-1)(1,591 W m^(-3)Hz^(-1)),which is 5.36-fold of the latest DC-TENG.In particular,the FEM-TENG with high durability(100%)truly realizes the collection of breeze energy and continuously drives 50 thermohygrometers.Four additional applications exemplify the FEM-TENG,enabling comprehensive sensing of land,water,and air.This work proposes a paradigm strategy for the in-depth utilization of dielectric films,aiming to enhance the output power of DC-TENGs.
