• Composites Research
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• v.34 no.6
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• pp.357-372
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• 2021

The energy harvesting device is known to be promising as an alternative to solve the resource shortage caused by the depletion of petroleum resources. In order to overcome the limitations (environmental pollution and low mechanical properties) of piezoelectric elements capable of converting mechanical motion into electrical energy, many studies have been conducted on a polymer matrix-based composite piezoelectric energy harvesting device. In this paper, the output performance and related applications of the reported piezoelectric composites are reviewed based on the applied materials and processes. As for the piezoelectric fillers, zinc oxide, which is advantageous in terms of eco-friendliness, biocompatibility, and flexibility, as well as ceramic fillers based on lead zirconate titanate and barium titanate, were reviewed. The polymer matrix was classified into piezoelectric polymers composed of polyvinylidene fluoride and copolymers, and flexible polymers based on epoxy and polydimethylsiloxane, to discuss piezoelectric synergy of composite materials and improvement of piezoelectric output by high external force application, respectively. In addition, the effect of improving the conductivity or the mechanical properties of composite material by the application of a metal or carbon-based secondary filler on the output performance of the piezoelectric harvesting device was explained in terms of the structure of the composite material. Composite material-based piezoelectric harvesting devices, which can be applied to small electronic devices, smart sensors, and medicine with improved performance, can provide potential insights as a power source for wireless electronic devices expected to be encountered in future daily life.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.135-145
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• 2022

This paper presented a method to build a predictable smart ammunition logistics system using the 4th industrial technology for ammunition logistics, which is the core functions in the field of defense and logistics. We have analyzed the current level of ammunition logistics with various perspectives such as domestic and overseas logistics policies, technology trends, ammunition logistics characteristics, the smart logistics certification measures by Ministry of Land, Infrastructure and Transport. As a result it is considered that the current ammunition logistics needs needs improvement. To improve this, we presented a direction based on the implications derived after analyzing various ongoing programs such as wired/wireless-based automation, smart ammunition depots, and logistics innovation of the army, navy, and air force that can be applied to the ammunition logistics. In order to implement a data-based smart ammunition logistics management system that can achieve innovation and efficiency of total life cycle while meeting changes in the battlefield environment, we presented 4 objectives such as "automation and modernization of field work", "3D-based storage management & improvement of issuing at war," and "data management for prediction-oriented ammunition management". it is expected that there will be benefits such as improvement of operational continuity, guarantee of ammunition reliability, budget reduction, improvement of inefficiencies such as delay, waiting, and double work, and reduction of accidents.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.491-496
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• 2021

In line with the modern era in which the safety of underground facilities and the use of underground information are increasingly emphasized, the state is pushing for more precise and accurate underground spatial information to be secured and utilized. Therefore, we need to pay more attention to subsurface geospatial data. In the future, the Ministry of Land, Infrastructure and Transport will actively utilize the 15 types of Integrated Underground Geospatial Information Map(6 types of underground facilities, 6 types of underground structures, 3 types of ground) that the Ministry of Land, Infrastructure and Transport is building as three-dimensional underground spatial information, and contribute greatly to improving national safety and convenience in underground construction. expected to do However, when a site manager requests an Integrated Underground Geospatial Information Map with a mobile device, if the large-capacity integrated underground space map is not quickly transmitted over the wireless section and is not serviced, it causes inconvenience to the site manager and delays work. In this paper, the goal of this paper is to enable field managers to quickly receive a tiled Integrated Underground Geospatial Information Map with minimal information exchange. Therefore, the tiling system is configured according to the dataset for high-speed Mobile Integrated Underground Geospatial Information Map transmission. In addition, a transmission system for the Mobile Integrated Underground Geospatial Information Map is established, and a TCP/IP (Transmission Control Protocol/Internet Protocol)-based spatial information tiling transmission protocol dedicated to the on-site Integrated Underground Geospatial Information Map is developed.

• Journal of Korean Physical Therapy Science
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• v.29 no.3
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• pp.12-20
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• 2022

Background: The purpose of this study was to investigate the changes of trunk and lower extremity muscle activity according to the compensation of arm during bridge movement of healthy subject. Design: Cross-sectional Study. Methods: Twenty healthy subjects participated in this study. The subjects performed bridge exercise with 3 different arm positions(arm abduction 45°, 90° and cross-arms) and measured the muscle activity of the trunk and lower extrimity. During bridge exercise with 3 different arm positions, trunk (rectus abdominis, erector spinae) and lower extrimity muscle activity (gluteus medius, biceps femoris, tibialis anterior) were measured using wireless surface EMG. Results: Rectus abdominis and gluteus medius muscle were most activated during bridge exercise with arm abduction 90° and erector spinae and biceps femoris muscle were most activated during bridge exercise with arm abduction 45°. In addition, tibialis anterior muscle was most activated during bridge exercise with arm cross. However, these difference in muscle activity according to the arm position was not statistically significant. Conclusion: As a result of this study, we think that the change in arm position does not induce sufficient instability to increase the muscle activity of the trunk and lower extremity muscles. Therefore, various approaches for inducing instability of the support surface for increasing muscle activity when applying bridge movement in clinical practice should be explored.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.569-575
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• 2022

It is most desirable to build a crane training program in the same evvironment as the actual port, but it has problem such as time constraint and cost. To overcome these limitations, next-generation training programs based on AR/VR are receiving a lot of attention. In this paper, a prototype of a harbor crane training system based on virtual reality was designed and implemented. The system implemented in this paper consists of two elements: an Arduino-based IoT terminal and an HMD equipped with a Unity application program. The IoT terminal consists of 2 controllers, 2 toggle switches, and 8 button switches to process data generated according to the user's operation. The HMD uses Oculus Quest2 and is connected to the IoT terminal through wireless communication to provide user convenience. The training system implemented in this paper is expected to provide trainees with a training environment independent of time and place through virtual reality and to save time and money.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.23-30
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• 2023

This study was conducted to analyze the correlation between egg breakage rate and cumulative external forces on eggs during the egg transfer system in 12 commercial layers farms. The commercially available electronic egg device was used to detect the external forces on eggs during egg collection systems. In addition, egg breakage rate per farm was collected. It was found that the external force on eggs were greater in the order of washer and dryer connection part, conveyor connection part, transfer, sorter, collecting elevator, packer, egg transfer connection part, and egg tray. A positive relationship between the external forces on eggs during egg transit system and the incidence of cracked eggs per farm was noted. The external forces on eggs varied from 5G to 38G depending on the location and the egg breakage rate ranged from 3.2 to 14.5% per farm. Although efforts to produce eggs with high eggshell quality are considered important, extra care should be made to lower the external forces on eggs during the egg transfer system from laying house to egg packing center.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.125-131
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• 2023

In this paper, research was conducted to solve the problem of reducing the dimming level and flicker that occurs in the visible light communication system. Visible light communication is a convergence technology that provides both communication and lighting, and must satisfy not only communication performance but also lighting performance. However, since the existing data transmission method transmits without considering the transmission data sequence, it reduces the dimming level and causes a flicker phenomenon. To solve this problem, in this paper, the Dimming Improvement and Flicker Reduction Mapping technique was studied. Existing systems simply transmitted data of '0' and '1', but in this system, original data transmission channels and DIFR (Dimming Improvement and Flicker Reduction) transmission channels are assigned to RGB channels. Original data is allocated to the R channel and original data or inverse original data is allocated to the DIFR-G channel, and the DIFR-B channel maintains the maximum dimming level by transmitting through the logical operation of the R channel and the G channel. At the same time, the flicker phenomenon is prevented by preventing continuous occurrence of 'OFF' patterns. Through this, we proposed an adaptive data allocation algorithm that can faithfully play a role as a light as well as a communication function.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.133-143
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• 2023

As drones (also known as UAV) become popular with advanced information and communication technology (ICT), they have been utilized for various fields (agriculture, architecture, and so on). However, malicious attackers with advanced drones may pose a threat to critical national infrastructures. Thus, anti-drone systems have been developed to respond to drone threats. In particular, remote identification data (R-ID)-based UAV detection and identification systems that detect and identify illegal drones with R-ID broadcasted by drones have been developed, and are widely employed worldwide. However, this R-ID-based UAV detection/identification system is vulnerable to security due to wireless broadcast characteristics. In this paper, we analyze the security vulnerabilities of DJI Aeroscope, a representative example of the R-ID-based UAV detection and identification system, and propose a replay-attack-based neutralization method using the analyzed vulnerabilities. To validate the proposed method, it is implemented as a software program, and verified against four types of attacks in real test environments. The results demonstrate that the proposed neutralization method is an effective neutralization method for R-ID-based UAV detection and identification systems.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.1
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• pp.1-8
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• 2009

The objective of this study is to design a system that automatically monitors the state of interior spaces like offices where lots of people are coming and going through image data and environment data, which includes temperature, humidity, and other conditions, and implement and test related application programs. In practice, there are lots of image data automatically obtained by unmanned equipments, such as certain types of CCTVs, for monitoring situation in usual interior spaces. This image data can be used as a more effective manner by establishing a system that recognizes situation in specific interior spaces based on the relationship between image and environment data. For instance, it is possible to perform unmanned on/off controls for various electronic equipments, such as air conditioners, lights, and other devices, through analyzing the data acquisited from environment sensors (temperature, humidity, and illumination) as dynamic states are not maintained for a specified period of time. For implementing these controls, this study analyzes environment data acquisited from temperature and humidity sensors and image data input from wireless cameras to recognize situation and that can be used to automatically control environment variables configured by users. Experiments were applied in a laboratory where unmanned controls were effectively performed as automatic on/off controls for the air conditioner and lights installed in the laboratory as certain motions were detected or undetected for a specified period of time.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.619-625
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• 2023

In this paper, the remote care of medical beds with multiple body pressure sensors is described. Falling is one of the factors that seriously threaten the safety of patients and harm their health. In this study, a new bed was developed to overcome this. The bed system consists of a keyboard that can operate, a keyboard controller that manages the movement of the keyboard, a sensor that measures body pressure, a sensor controller that transmits and receives sensor values, a main controller that checks it and operates automatically or manually according to the algorithm, and a server that oversees all these information. The bed system checks the patient's location through a sensor and wirelessly alerts the server through the main controller when the patient determines that there is a risk of falling, so that the nurse or nurse can recognize the patient's dangerous condition. The server may receive state data transmitted from the wired/wireless terminal to monitor whether the bed system is operating normally. The controller of the keyboard operates a keyboard-type mechanism and automatically controls the prevention of bedsores connected by body pressure sensors to physically separate the area to which the patient's pressure is applied to prevent bedsores. The main controller checks the presence of the patient's bed and transmits it to the server. In conclusion, the proposed system can smart monitor the user's state and perform remote care.