• Journal of IKEEE
• /
• v.25 no.4
• /
• pp.703-709
• /
• 2021

As drone technology advances, the risks of drones are increasing, then technology to detect drones is becoming important. In this thesis, it was verified that miniaturized and lightweighted active array antenna could be used for radar system to detect drones in reality. The transmit-receive module was designed in the form of tile-type to simplify interconnections between devices. The waveform generation module and the down conversion module were miniaturized to include in one body too. As a result of verifing the detection performance through test, it was confirmed that the detection range was over 3.7Km.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.18 no.4
• /
• pp.185-194
• /
• 2023

Currently, drones are used in various fields such as transportation, agriculture and military. Especially, drones for military use are developed and utilized in many ways such as reconnaissance and bombing to minimize one's own damages. Nevertheless, they are developed as new weapons of modern types, so it is difficult to use them together with existing weapons. In this study, a drone program for effective bombing of mortar, which is often used in modern warfare, is developed. In mortar, a forward soldier comprehends the location of enemy for its distance and altitude, input them in data computer of launching angle, and applies the result value to cannon to launch. However, the existing method has low accuracy of bombing because observing shall be done within 1km from the target, and measuring accurate direction and velocity of the wind is difficult. Whereas, in the program of this study, the location of target, GPS, direction and velocity of the wind, and altitude are measured through drone. Each digit is used to calculate bombing specification for optimal bombing through the calculating formula of launching angle. In addition, when specifications are input in the program, the calculation is done automatically, so that it can be used in various mortars and shells. With the use of the program in this study, the location of enemy can be comprehended, and bombing specifications can be calculated quickly. It also enables the intensity of the wind to be applied for accurate bombing.

• Journal of the Korea Institute of Building Construction
• /
• v.23 no.3
• /
• pp.327-336
• /
• 2023

The focus of this research was to devise a conceptual methodology for drone usage and to assess the viability of safety checklist items specific to drone application in safety oversight. The appraisal was grounded in a focus group interview involving professionals from construction management and safety fields. The proposed process was segmented into four stages: 1) pre-flight phase for flight plan development, 2) drone flight phase for safety condition inspection utilizing checklist items, 3) post-flight phase for visual asset analysis, and 4) documentation and management phase. Furthermore, the research scrutinized the applicability of 32 distinct safety checklist items for drone operations. The primary aim of this investigation was to probe the possible deployment of drones as part of construction safety inspections at work sites. However, it bears mentioning that subsequent research should strive to gather a more extensive sample size through questionnaire surveys, thereby facilitating quantitative analysis. Administering such surveys would yield more comprehensive data compared to a focus group interview, which was constrained by a limited participant count. In summation, this study lays a foundational groundwork for understanding the potential advantages and challenges associated with integrating drones into construction safety management.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.18 no.2
• /
• pp.75-80
• /
• 2023

Unmanned drone stations for automatic charging have been developed in order to overcome the flying time limitation of rotary wing drones. Since the drone stations is an unmanned operating system, each of the drones will be required to have a high degree of landing accuracy. Drone precision landing has been mainly studied depended on image processing technologies, but the image processing systems make several problems, such as the mission weight, the drone cost, and the development complexity increases, and the flight time decrease. Thus, this paper researched accuracy of precision landing based on RTK (real time kinetics) for rotary wing drones. For the experiments of RTK based precision landing, a drone repeatedly performed three missions. The survey accuracies of the RTK about missions respectively were set as 0.3, 0.2, and 0.1 meters. Each mission has one take-off point, two way-points and one landing-point, and was repeated ten times. The experiment results revealed landing error distance means of around 0.258, 0.12 and 0.057 meters on each of RTK setting.

• Journal of IKEEE
• /
• v.27 no.4
• /
• pp.439-449
• /
• 2023

In an era marked by the increasing use of drones and the growing demand for indoor surveillance, the development of a robust application for detecting and tracking both drones and humans within indoor spaces becomes imperative. This study presents an innovative application that uses FMCW radar to detect human and drone motions from the cloud point. At the outset, the DBSCAN (Density-based Spatial Clustering of Applications with Noise) algorithm is utilized to categorize cloud points into distinct groups, each representing the objects present in the tracking area. Notably, this algorithm demonstrates remarkable efficiency, particularly in clustering drone point clouds, achieving an impressive accuracy of up to 92.8%. Subsequently, the clusters are discerned and classified into either humans or drones by employing a deep learning model. A trio of models, including Deep Neural Network (DNN), Residual Network (ResNet), and Long Short-Term Memory (LSTM), are applied, and the outcomes reveal that the ResNet model achieves the highest accuracy. It attains an impressive 98.62% accuracy for identifying drone clusters and a noteworthy 96.75% accuracy for human clusters.

• Journal of Wind Energy
• /
• v.14 no.3
• /
• pp.100-108
• /
• 2023

The aim of this study is to develop guidelines for predicting interference between drones and wakes during non-destructive blade inspections in wind power systems. The wake generated by wind towers and blades can affect the stability of drone flights, necessitating the establishment of guidelines to ensure safe and efficient inspections. In order to predict the interference between drones and blades, environmental variables must be considered, including quantification of turbulence intensity in the wake generated by the tower and blades, as well as determining the appropriate distance between the drone and the tower/blades for flight stability. To achieve this, computational fluid dynamics (CFD) analysis was performed using cross-sectional geometries corresponding to the main wind turbine blade and tower span locations. Based on the CFD analysis results, a safe flight path for drones is proposed, which minimizes the risk of collision and interference with towers and blades during maintenance operations of wind power systems. Implementation of the proposed guidelines is expected to enhance the safety and efficiency of maintenance work.

• Korean Journal of Agricultural Science
• /
• v.50 no.3
• /
• pp.427-435
• /
• 2023

This study was conducted to evaluate the spraying performance according to the flight conditions of agricultural drones for the development of a variable control system. The analyzed flight conditions comprised six factors: spraying direction, flight speed, altitude, wind speed, wind direction, and rotor rotational speed. The ratio of the area sprayed on the water-sensitive paper was used as the coverage, and the distribution and amount of the coverage were evaluated. The coverage distribution based on the distance from the drone was used to evaluate a spray pattern, and the distribution was expressed as a Gaussian function approximation. In addition, the probability distribution based on coverage was expressed as the cumulative probability via Gamma function approximation to analyze the spraying efficiency in the target area. The results showed that the averaged coverage decreased significantly as the flight speed and wind speed increased, and the wind direction changed the spray pattern without a coverage decrease. This study contributes to the development of a control technique for the precision control system of agricultural drones.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.7
• /
• pp.1929-1952
• /
• 2024

The development of drones is transforming society as a whole and playing a game-changing role in warfare. However, numerous problems pose threats to the lives and safety of people, and the counter-drone system lags behind the rapid development of drones. Most countries, including South Korea, have not established a reliable counter-drone system in response to the threat posed by numerous drones. Due to budget constraints in each country, an Analytic Hierarchy Process (AHP) analysis was conducted among a group of experts who have been involved in policymaking and research and development related to counter-drone systems. This analysis aimed to determine the priority of building a counter-drone system. Based on various research data, the counter-drone system was analyzed in three stages: detection/identification, governance, and response. The hierarchical design mapped out the existing researched counter-drone technology into a hierarchical model consisting of 31 evaluation criteria. The conclusion provided a roadmap for establishing a counter-drone system based on the prioritization of each element and considering factors such as technological advancement, outlining directions for development in each field.

• The Korean Journal of Air & Space Law and Policy
• /
• v.32 no.1
• /
• pp.53-81
• /
• 2017

Targeted killing is a modern euphemism for the assassination of an individual by a state organization or institution outside a judicial procedure or a battlefield. Targeted killing using armed drones has raised profound anxieties in legal, policy, and advocacy communities in the United States and abroad, including among UN officials. The bottom line for targeted killing supporters is that targeted killing works as part of a larger counter-terrorism strategy. Targeted killing does what it is supposed to and removes the leader of a group. And despite growing legal, moral, and ethical issues concerning targeted killing, scholars agree that drone strikes and targeted killing operations will stay. The ACLU has sued top CIA and Pentagon decision-makers to seek accountability for the unlawful killings of three U.S. citizens in Yemen last year. Also, strikes by drones are associated with serious problems such as collateral damage to ordinary citizens and friendly fire. Targeted killings by drones also involves several issues to be resolved, including suspicions that they may run counter to domestic law prohibiting assassination, the opacity concerning their definitions and military actions, and the impact of whiplash transition. Finally, targeted killing program and the need for transparency. The assembly referring to resolution invites the committee of ministers to undertake a thorough study of the lawfulness of the use of combat drones for targeted killings and if need be develop guidelines for member states on targeted killings with a special reference to those carried out by combat drones. These guidelines should reflect the states duties under international humanitarian and human rights law in particular the standards laid down in the EC on human rights as interpreted by the european court of human rights.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.12-19
• /
• 2020

The clustered heterogeneous wireless sensor network is comprised of sensor nodes and cluster heads, which are hierarchically organized for different objectives. In the network, we should especially take care of managing node resources to enhance network performance based on memory and battery capacity constraints. For instances, if some interesting events occur frequently in the vicinity of particular sensor nodes, those nodes might receive massive amounts of data. Data congestion can happen due to a memory bottleneck or link disconnection at cluster heads because the remaining memory space is filled with those data. In this paper, we utilize drones as mobile sinks to resolve data congestion and model the network, sensor nodes, and cluster heads. We also design a cost function and a congestion indicator to calculate the degree of congestion. Then we propose a data congestion map index and a data congestion mapping scheme to deploy drones at optimal points. Using control variable, we explore the relationship between the degree of congestion and the number of drones to be deployed, as well as the number of drones that must be below a certain degree of congestion and within communication range. Furthermore, we show that our algorithm outperforms previous work by a minimum of 20% in terms of memory overflow.