• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.156-162
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• 2020

Wireless Sensor Network (WSN) field is mainly studied to monitor and characterize large-scale physical environments to track various environmental or physical conditions, such as temperature, pressure, wind speed and humidity. WSN can be used in various applications such as wild surveillance, military target tracking and monitoring, dangerous environmental exploration and natural disaster relief. We design probabilistic mobile models that apply to mobile ad hoc network mobile environments. A probabilistic shift model proposed by dividing the number of moving nodes and the distance of travel into two categories to express node movement characteristics. The proposed model of movement through simulation was compared with the existing random movement model, ensuring that the width and variation rate of the first node node node node (FND) was stable regardless of the node movement rate. In addition, when the proposed mobile model is applied to the routing protocol, the superiority of network life can be verified from measured FND values. We overcame the limitations of the existing random movement model, showing excellent characteristics in terms of energy efficiency and stable in terms of changes in node movement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.118-128
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• 2012

The goal of this paper is to design the target tracking controller for a quadrotor micro UAV using a vision sensor. First of all, the mathematical model of the quadrotor was estimated through the Prediction Error Method(PEM) using experimental input/output flight data, and then the estimated model was validated via the comparison with new experimental flight data. Next, the target tracking controller was designed using LQR(Linear Quadratic Regulator) method based on the estimated model. The relative distance between an object and the quadrotor was obtained by a vision sensor, and the altitude was obtained by a ultra sonic sensor. Finally, the performance of the designed target tracking controller was evaluated through flight tests.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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• pp.97-109
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• 2005

In this paper, the critical requirement for obstacle awareness and avoidance is assessed with the compliance of the equivalent level of safety regulation, and then the collision avoidance sensor system is presented with the key design parameters for the requirement of the smart unmanned aerial vehicle in low-altitude flight. Based on the assessment of various sensors, small-sized radar sensor is selected for the suitable candidate due to the real-time range and range-rate acquisition capability of the stationary and moving aircraft even under all-weather environments. Through the performance analysis for the system requirement, the conceptual design result of radar sensor model is proposed with the range detection probability and collision avoidance mode is established based on the time-to-collision, which is analyzed by collision scenario.

• Journal of the Korean Institute of Navigation
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• v.12 no.2
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• pp.33-42
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• 1988

As a basic study for enhancing the sensitivity of the follow-up system of the marine gyrocompass, the geometric characteristics of the deflection sensor were investigated and the theoretical model of it was formulated. The output signal voltage of the deflection sensor was esamined by changing the attitude of gyrosphere against follow-up container. The characteristics of the output are found to be indentical with those of the distance difference versus the relative azimuthal deflection of the gyrosphere against the follow up container. On the base of the theoretical model, some useful points for the design of the deflection sensor are suggested as following : 1. When the difference between semidiamter of gyrophere and that of the follow-up container decreases, the sensitivity of deflection sensor increases. 2. If the semidiameter difference of two spheres is constant, the sensitivity of deflection sensor is proportional to the magnitude of the semidiamter of each sphere. 3. The farther the gyrosphere is deviated from the center of follow-up container, the higher the sensitivity of deflection sensor is. 4. It is recommendable that the value of the datum deflection of the electrodes on the gyrosphere should be within the range between $4^{\circ}$ and $16^{\circ}$deviated from north-south line.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.93-99
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• 2021

The sensor networks should be appropriately designed by applied network purpose, so that they can support proper application functions. Based on the design of suitable network model, the network lifetime can be maximized than using other general strategies which have not the consideration of specific network environments. In this paper, we propose a non-deterministic agent scheme to the mobile sink in distributed wireless sensor networks. The sensor network area can be divided into several sensor regions. Hence, to these such networks, the specified suitable scheme is requested by the applied network model to implement satisfactory network management. In this paper, we theoretically represent the proposed scheme, and provide the evaluation with the simulation results.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.1-9
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• 2023

The skin structure of sensor pod mounted on the exterior of aircraft can be exposed to the acoustic dynamic load and static load such as aerodynamic pressure and inertial load during flight. Fatigue life prediction of structural model under acoustic load should be performed and also differential stiffness of model modified by static load should be considered. The acoustic noise test spectrum of MIL-STD-810G was applied to the structural model and the stress response power spectral density (PSD) was calculated. The frequency response analysis was performed with or without prestress induced by inplane static load, and the response spectrum was compared. Time series data was generated using the calculated PSD, and the time and frequency domain fatigue life were predicted and compared. The variation of stress response spectrum due to static load and predicted fatigue life according to the different structural model considering mean stress were examined and decreasing fatigue life was observed in the model with prestress of compressive static load.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.250-254
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• 2001

The resolution of analog sensor is determined by its sensitivity and amplitude of noise. This paper presents modeling of inductive gap sensor base on equivalent magnetic circuit and analysis of sensitivity. We can simulate static characteristic of inductive gap sensor using this model. Computer simulation show that sensor's sensitivity is affected by magnetic flux's leakage and fringing, and that they are affected by shape of sensor probe. Base on this, we designed shape of inductive position sensor probe.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.6_2
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• pp.577-583
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• 2013

Recently, massive archives of ground information imagery from new sensors have become available. To establish a functional relationship between the image and the ground space, sensor models are required. The rational functional model (RFM), which is used as an alternative to the rigorous sensor model, is an attractive option owing to its generality and simplicity. To determine the rational polynomial coefficients (RPC) in RFM, however, we encounter the problem of obtaining a stable solution. The design matrix for solutions is usually ill-conditioned in the experiments. To solve this unstable solution problem, regularization techniques are generally used. In this paper, we describe the effective determination of the optimal regularization parameter in the regularization technique during RPC derivation. A brief mathematical background of RFM is presented, followed by numerical approaches for effective determination of the optimal regularization parameter using the Euler Method. Experiments are performed assuming that a tilted aerial image is taken with a known rigorous sensor. To show the effectiveness, calculation time and RMSE between L-curve method and proposed method is compared.

• Journal of information and communication convergence engineering
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• v.19 no.3
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• pp.136-141
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• 2021

Research on wireless sensor networks has focused on the monitoring and characterization of large-scale physical environments and the tracking of various environmental or physical conditions, such as temperature, pressure, and wind speed. We propose a stochastic mobility model that can be applied to a MANET (Mobile Ad-hoc NETwork). environment, and apply this mobility model to a newly proposed clustering-based routing protocol. To verify its stability and durability, we compared the proposed stochastic mobility model with a random model in terms of energy efficiency. The FND (First Node Dead) was measured and compared to verify the performance of the newly designed protocol. In this paper, we describe the proposed mobility model, quantify the changes to the mobile environment, and detail the selection of cluster heads and clusters formed using a fuzzy inference system. After the clusters are configured, the collected data are sent to a base station. Studies on clustering-based routing protocols and stochastic mobility models for MANET applications have shown that these strategies improve the energy efficiency of a network.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.6
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• pp.630-637
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• 1991

For the measurement of time-varying electric fields and related quantities, a field sensor should be sensitive to the field to be measured, and also designed having an accurate transfer function. In this paper, a theoretical model which adequately describes the operation principle and design of the sensor is presented. A calibration and/or correction technique of the sensor is also studied which enables a precise determination of the response of the sensor to an electric field. As a result, the developed electric field sensor and measuring system are known to be accurate within a bandwidth from a few Hz to 200 MHz. It is found that the sensor can be used directly in the measurement of very fast transient voltages and time-varying electric fields occurring during disconnector operations in a gas-insulated substation. It may be useful also for the study on the electromagnetic environmental parameters.