• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.12
• /
• pp.974-981
• /
• 2017

Globally, owing to the rapid expansion of radio stations overseas, the frequency coordination system is managed as a preconditioning system. As a result, it is predicted that many types of radio stations will be established for domestic purposes, such as 5G, low-power IoT devices with long distance, based on licenses and non-license in the future. Many problems such as unnecessary launching of radio resources and spectrum-sharing technology exist, and it is necessary to consider the introduction of the abovementioned system and other plan system. In this paper, we explore the outline of radio station licensing and introduce the contents of the survey on another industry licensing. The plans were studied by discussing problems that may occur in future, through comparative analysis of radio stations and other industry licensing. Moreover, the differences were compared and analyzed using graphs. Finally, we discussed the problems convergence products such as drone may offer in the future.

• Journal of the Korea Convergence Society
• /
• v.11 no.11
• /
• pp.195-201
• /
• 2020

This paper implemented quadcopter-type drone system and proposed the heuristic method for obtaining the optimum gain coefficients in order to minimize the settling time. Control system for quadcopter posture stabilization reads the posture data from accelerator and gyro sensor, revises the original posture data using Mahony filter, and drives 4 DC motors using PID controller. The first step of the proposed method is to obtain the gain coefficients using the Ziegler-Nichols method, and then determine the optimum gain coefficients using the heuristic method at the next 3 steps. The experimental result shows that the maximum overshoot decreases from 44.3 to 29.8 degrees and the settling time decreases from 2.6 to 1.7 seconds compared to the Ziegler-Nichols method. Therefore, we proved that the proposed method works well in quadcopter flight system with high motor noise while reducing trial and error to obtain the optimal PID gain coefficients.

• Journal of IKEEE
• /
• v.23 no.4
• /
• pp.1116-1121
• /
• 2019

Networking services based on the flying drones may cause many handover events because the coverage radius is narrower than that of the existing infrastructure, such as cellular networks. Therefore, it copes with frequent handover by pre-caching data to target network provider before handover using a content store. As a result of the simulation, it can be confirmed that the delay is lowered. This is because the data that was requested before the handover is delivered to the target drones, and the car that has completed the handover receives the data through the target drones. On the other hand, if the proposed method is not used, it can be confirmed that the delay is increased. This is because it can not cope with the path change due to the handover and re-sends the packet requesting the data.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.7
• /
• pp.610-617
• /
• 2017

In the recent weapon system trend, it is required to develop small and low cost guidance missile to track and strike the enemy target effectively. Controling the such small drone typed weapon demands a integrated electronic device that equipped with not only a wireless network interface, a high resolution camera, various sensors for target tracking, and position and attitude control but also a high performance processor that integrates and processes those sensor outputs in real-time. In this paper, we propose the android smartphone as a solution for that and implement the guidance and control application of the missile. Furthermore, the performance of the implemented guidance and control application is analyzed through the simulation.

• Korean journal of applied entomology
• /
• v.39 no.2
• /
• pp.99-103
• /
• 2000

The green lacewing, Chrysopa pallens (Rambur), was reared on artificial diets supplementedwith natural products such as lyophilized beef liver, silk worm pupae powder and drone honey beepowder. The performance of the green lacewing was improved siginificantly on only the diet to whichadded 1 % of silk worm pupae powder (wt/v). Larval developement was completed in 15.6 f 0.99 days,cocoon weight was 16.4f2.94 mg, and suvival to adult was 89.3% at 27$^{\circ}$C. And another diet made bymixing 4 part of lyophilized beef liver powder, 4 part of lyophilized beef powder, 3 part of lyophilizedchicken egg, 4 part of sucrose, and 50 mg each of vitamin C and Vanderzant's vitamin B mixture waspromising. Larval development of the green lacewing on this diet was completed in 12.7 f 1.45 days at27"C, pupal weight was 18.1 f 2.24mg, suvival to adult was loo%, and 633f70.4 eggs were laid in 20days after beginning of oviposition.ginning of oviposition.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.10
• /
• pp.857-864
• /
• 2016

Many plane, UAV and drone fly in the sky as development of aviation industry. Plane and UAV fly and drone's propellers rotate so fast. Impact between flying objects which have high velocity threats passengers. Also the impact damages people, building and various property. Plane's operating speed is near sound velocity(340m/s), and propeller's rotating speed is less than that. Until now, impact experiment uses gas gun to get speed and the gun needs large space to entirely air expansion. Electromagnetic launcher, especially railgun, needs smaller space than gas gun to get enough speed about 500m/s. This paper explains electromagnetic launcher's operating principle, shows making electromagnetic launcher design guide line and suggests that it is a better apparatus to get low-high velocity.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.6
• /
• pp.874-880
• /
• 2018

3D modeling is extensively used in the field of architecture, machinery and contents production such as movies. Modeling is a time-consuming task. In order to compensate for these drawbacks, attempts have recently been made to reduce the production period by applying 3D scanning technology. 3D scanning for small objects can be done directly with laser or optics, but large buildings and sculptures require expensive equipment, which makes it difficult to acquire data directly. In this study, 3D modeling data for a large object is acquired using photometry with using drones to acquire the image data. The maintenance method for uniform spacing between the sculpture and the drone, the measurement method for the flight line were presented. In addition, we presented a production environment that can utilize the obtained 3D point cloud data for animation and a rendered animation result to find ways to make it in various environments.

• Journal of Korean Society of Disaster and Security
• /
• v.12 no.4
• /
• pp.53-61
• /
• 2019

Occurrences of debris flow are a serious danger to roads and residential located in mountainous areas and cause a lot of property loss. In this study, two basins were selected and spatial data were constructed to simulate the occurred debris flow from mountainous areas. The first basin was to use the Terrestrial LiDAR to scan the debris flow occurrence section and to build terrain data. For the second basin, use drones the sediment in the basin was photographed and DSM (Digital surface model) was generated. And to analyze the effect of the occurrence of debris flow on downstream side, FLO-2D, two-dimensional commercial model, was used to simulate the flow region of the debris flow. And it was compared with the sedimentation area of terrestrial LiDAR and drone measurement data.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.23 no.1
• /
• pp.143-146
• /
• 2011

Some of men have been suffered from the insufficient secretion of testosterone causing by physical factors, social and psychological factors. Testosterone is an essential steroid hormone controlling male reproductive function. Alternative medicines in plants, fungi, and insects have been studied to enhance sexuality. $Cordyceps$ species including $Cordyceps$ $sinensis$ (CS) and $C.$ $militaris$(CM) has been used as for the enhancement of sexual functionfor hundreds of years in Far East Asian. In the present study, we determined the effect of fruiting bodies of $C.$ $militaris$ which cultured on bee drone medium (CMD) and brown rice medium (CMB) on testosterone concentration in Sprague-Dawley rats. Eighteen rats per group were housed to regular diet or diet supplemented with CMB and CDD, respectively for 4 weeks. Serum was collected from 6 rats per group. Results showed that changes of the body weight, food and water intake of the rats were not observed in this study. However, both CMB and CDD increased the serum testosterone concentration in rats. Furthermore, CMD significantly stimulated testosterone production (p <0.05) compared to the control. Hence, it suggests that $C.$ $militaris$ fruiting bodymight be developed as a complementary medicine to improve sexual hormones.

• Journal of the Institute of Convergence Signal Processing
• /
• v.20 no.4
• /
• pp.186-192
• /
• 2019

In general, many marine organisms are attached to the bottom of a ship in operation or a ship in construction. Due to this phenomenon, the roughness of the ship surface increases, resulting in loss of ship speed, resulting in economic losses and environmental pollution. This study acquires / utilizes camera images attached to ship's bottom and underwater drones to check the condition of bottom. The acquired image will determine the roughness according to marine life by the administrator's visual confirmation. Therefore, by applying a filter algorithm to correct the image to the original image can help in the correct determination of whether or not attached to marine life. Various correction filters are required for the underwater image correction algorithm, and the lighting suitable for the dark underwater environment has a great influence on the judgment. The results of the research test according to the calibration algorithm and the roughness of each algorithm are considered to be applicable to many fields.