• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.742-756
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• 2022

A flood of information has occurred with the rise of the internet and digital devices in the fourth industrial revolution era. Every millisecond, massive amounts of structured and unstructured data are generated; smartphones, wearable devices, sensors, and self-driving cars are just a few examples of devices that currently generate massive amounts of data in our daily. Machine learning has been considered an approach to support and recognize patterns in data in many areas to provide a convenient way to other sectors, including the healthcare sector, government sector, banks, military sector, and more. However, the conventional machine learning model requires the data owner to upload their information to train the model in one central location to perform the model training. This classical model has caused data owners to worry about the risks of transferring private information because traditional machine learning is required to push their data to the cloud to process the model training. Furthermore, the training of machine learning and deep learning models requires massive computing resources. Thus, many researchers have jumped to a new model known as "Federated Learning". Federated learning is emerging to train Artificial Intelligence models over distributed clients, and it provides secure privacy information to the data owner. Hence, this paper implements Federated Averaging with a Deep Neural Network to classify the handwriting image and protect the sensitive data. Moreover, we compare the centralized machine learning model with federated averaging. The result shows the centralized machine learning model outperforms federated learning in terms of accuracy, but this classical model produces another risk, like privacy concern, due to the data being stored in the data center. The MNIST dataset was used in this experiment.

• The Journal of Art Theory & Practice
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• no.13
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• pp.7-33
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• 2012

The memory of the Korean War is about the time period when people lived toughly during evacuation, due to being exposed to the natural climate such as intense cold or heat without any protection, leaving their comfortable home and living in temporary built shelters which were barely enough to avoid the wind. 'Death is concealed and only the figures of evacuation for survival were expressed, just as how the government ordered. Since the experience of the battlefield is personal and fragmentary, that is broken into pieces, it does not have compatibility. As war is a distorted experience that cannot be placed in a big picture, it is not possible to take a view of the war's big picture. Having this individualized experience as a common collective memory is an issue and it is the will that people tries to pursue. The reason why the evacuees from north to south, and as well as from the south to further south were all able to be adopted as the theme of artworks due to the military action that emptied the occupied territories of the North Korean Army under the forced removal command. In such situations, the natural state of the 'snow' was like a symbol of the 1.4 Recession. The group of people who were thrown into the intense cold displaced the war damage of loosing their base livelihood, and symbolized the obedient citizens who faithfully follow their government's command. The figure of advocating anti-communism is projected as a figure of a refugee during cold winter-time and it contains ones past which he or she obeyed its own country's commands. Evacuation, especially the evacuation during the winter is a visual device that can confirm these kinds of country's command. The consequences were same for the artists as well. Therefore, the situation being communal could be found due to the individual experiences during war are ideological. The image of the refuge shown in the picture played the role of strengthening the consciousness of defecting to South Korea into the meaning of the 'Finding Freedom.' I would like to express that the reason of them leave their home during the harsh winter is in order to avoid the oppression of the Communist Party. The evacuation that people went through was not to 'Finding Freedom', but 'To Survive'. Later, this evacuation has been imprinted as a behavior of choosing free Republic of Korea, which was an ideological issue. Anti-communism was the rule of survival in South Korea society, and people have the tendency to remember what they want to remember. As it is not the people who possesses an incident, but the memory that possesses ones, people cover their memory with disguised plots in order to forget the violence and to live a different prologue. They share the incident of violence as a hurtful memory. The tragedy of the Korean War was the result of Ideology and being in between the powerful nations' rights, but the violence during the war has been depicted as a natural disaster, which was the evacuation in heavy snow.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.1
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• pp.23-29
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• 2014

The emergence of high resolution satellite images and the evolution of spatial resolution facilitate various studies using high resolution satellite images. Above all, target detection algorithms are effective for monitoring of traffic flow and military surveillance and reconnaissance because vehicles, airplanes, and ships on broad area could be detected easily using high resolution satellite images. Recently, many satellites are launched from global countries and the diversity of satellite images are also increased. On the contrary, studies on comparison about the spatial resolution or target detection, especially, are insufficient in domestic and foreign countries. Therefore, in this study, effects of spatial resolution on target detection are analyzed using the PSO target detection algorithm. The resampling techniques such as nearest neighbor, bilinear, and cubic convolution are adopted to resize the original image into 0.5m, 1m, 2m, 4m spatial resolutions. Then, accuracy of target detection is assessed according to not only spatial resolution but also resampling method. As a result of the study, the resolution of 0.5m and nearest neighbor among the resampling methods have the best accuracy. Additionally, it is necessary to satisfy the criteria of 2m and 4m resolution for the detection of airplane and ship, respectively. The detection of airplane need more high spatial resolution than ship because of their complexity of shape. This research suggests the appropriate spatial resolution for the plane and ship target detection and contributes to the criteria of satellite sensor design.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.341-369
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• 2005

Hyperspectral images have emerged as a new and promising remote sensing data that can overcome the limitations of existing optical image data. This study was designed to provide a comprehensive review on definition, data processing methods, and applications of hyperspectral data. Various types of airborne, spaceborne, and field hyperspectral image sensors were surveyed from the available literatures and internet search. To understand the current status of hyperspectral remote sensing technology and research development, we collected several hundreds research papers from international journals (IEEE Transactions on Geoscience and Remote Sensing, International Journal of Remote Sensing, Remote Sensing of Environment and AVIRIS Workshop Proceedings), and categorized them by sensor types, data processing techniques, and applications. Although several hyperspectral sensors have been developing, AVIRIS has been a primary data source that the most hyperspectral remote sensing researches were relied on. Since hyperspectral data have very large data volume with many spectral bands, several data processing techniques that are particularly oriented to hyperspectral data have been developed. Although atmospheric correction, spectral mixture analysis, and spectral feature extraction are among those processing techniques, they are still in experimental stage and need further refinement until the fully operational adaptation. Geology and mineral exploration were major application in early stage of hyperspectral sensing because of the distinct spectral features of rock and minerals that could be easily observed with hyperspectral data. The applications of hyperspectral sensing have been expanding to vegetation, water resources, and military areas where the multispectral sensing was not very effective to extract necessary information.

• Journal of Science and Technology Studies
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• v.6 no.1 s.11
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• pp.89-118
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• 2006

The formation of early korean scientific community is a dynamic process of korean modern history in which colonialization, liberation, United States Army Military Government and Korean War is included. Particularly, scientist's crossing over the border into north korea and south korea have profound effect on the early stage of our scientific community. This period is so important to understand the nature of korean scientific community that we need to re-interpret the role of 'ideology' in the development of scientific community. On the other hand, war is a important element in our formation of the image of the science. This study purported to interpret the problem of political ideology, it's role in the formation of early scientific society, it's implication on our idea of science positively. Also the study is a an attempt to re-construct the scientist's struggle(1945-1950) to demarcate new science from old, colonial science.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.185-196
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• 1997

By considering the definition and application of resolution as well as the concept and theory of SAR, the essential contents of the SAR design and analysis are described. This paper is to compare and analyze the resolution performance capability of three techniques for achieving azimuth resolution such as the real aperture, the unfocused and the focused techniques, through the simulation. Simulation is performed to make the restricted conditions for the unfocused technique that can be implemented by the less commputing load of signal processingand the lower cost. Through the mission analysis, the use of SAR image can be applied for estimation of whole situation at the regional area in the field of military demands for tactical purpose as well as civilian demands for the damage of disaster. RPV and sall or medium aircraft are selected to carry the SAR for these purposes and the proper resolution turns ou 5~15 m. The trade-off study of variables through the simulations results in the proper conditions such that range is less 3, 000 m, Wavelength is 1~10 m, and the raw signals and results processed by three techniques for two point targets are exhibited undr such conditions. Therefore, at some points, the result of this paper si proposed for useful applications of unforcused technique in the restricted conditions except the identification of the small target at a long range re- quired for high resolution.

• Journal of Korea Multimedia Society
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• v.11 no.9
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• pp.1204-1212
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• 2008

The vehicle simulation (flight simulator) in 1920's was the first in the virtual reality. With the development of precise optical and electromagnetic equipment, the virtual reality widened its application for other purposes than military one. Based on the realistic display technology, it is more and more common in the various areas such as entertainment, medical profession, learning, film, architectural design, tourism and etc. In 1989, Jaron Ranier was the first to use the terminology 'Virtual Reality'. With this term, all virtual projects could be classified in a single item. But even before the term was used, the virtual reality has been studied up to now. As a part of virtual reality, the human thirst for the impossible thing has led to the development of ride film. The ride film consists of the special technical elements as well as the psychological analysis of human being. The ultimate purpose of virtual reality is engrossment through interaction. Even though the real interaction requires interface, input sensor and reaction ability, the ride film is not an element of the typical interaction. The virtual reality is mostly defined in technical terms now. But in this study, we will analyze the concepts worked out by Professor Michael Haim who is called a philosopher in the cyberspace in aspect of experience-oriented definition. We will analyze the adaptability of virtual reality based on his concepts such as artificial reality/ interaction/ engrossment/ networked world/ remote display/ simulation/ onmon engrossment. And also, we aim to suggest the directions of developing the ride films for perfect engrossment and to draw optimized conclusion thereon. In this viewpoint, we consider that the study of ride film on which there were few case studies will contribute to level up the basic frameworks of IT technology and the digital image.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.98-105
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• 2013

This paper presents a finite-difference time-domain(FDTD) simulation and a data processing technique for radar sensing of the internal structure of a wall using an ultra-wide band antenna. We first designed an ultra-wide band anti-podal vivaldi antenna with a frequency range of 0.3~7 GHz which is chosen to be relatively low after considering the characteristics of wave attenuation, wall penetration, and range resolution. In this study the two-dimensional FDTD technique was used to simulate a wall-penetration-radar experiment under practical conditions. The next, the measured radiation pattern of the practical antenna is considered as an equivalent source in the FDTD simulation, and the reflection data of a concrete wall and targets are obtained by using the simulation. Then, a data processing technique has been applied to the FDTD reflection data to get a radar image for remote sensing of the internal structure of the wall. We compared the two different source excitations in the FDTD simulation; (1) commonly-used isotropic point sources and (2) polynomial curve fitting sources of the measured radiation pattern. As a result, when we apply the measured antenna pattern into the FDTD simulation, we could obtain about 2.5 dB higher signal to noise level than using a plane wave incidence with isotropic sources.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.127-136
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• 2002

DEM(Digital Elevation Model) is used widely in image processing, water resources, construction, GIS, landscape architecture, telecommunication, military operations and other related areas. And it is used especially in producing ortho-photo based on specific DEM and developing 3D GIS database vividly. As LiDAR(Light and Detection And Ranging) system emerged recently, DEM could be developed in urban area more efficiently and more economically, compared to the conventional DEM Production. Traditional method using check points for elevation has tome limitations in structure's height accuracy by LiDAR, because it uses only terrain height. Accordingly after the downtown of Chungju city was selected as a test field in this paper and DEM and digital ortho images was produced by way of LiDar survey, the accuracy was evaluated through analytical plotting map. The result shows that in case of buildings in LiDAR DEM, the accuracy is 0.30 m in X, 0.62 m in Y and RMS is 1.17 m. The difference distribution between DEM and plotting map in range of $\pm$10 cm was 36.2% and $\pm$10 cm $\pm$20 cm was 43.53%. The accuracy of LiDAR in this study meets 1/5,000 which is the regulation for map of NGI(National Geography Institute) and LiDAR can be possibly used in many other applied area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.1021-1029
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• 2018

The marine buoys are operated in various domains, which are navigation route and danger maker, weather and environment monitoring, military strategical element, etc. If the marine buoy is damaged, there consumes many cost and time for recovery or replacement, because of severe environmental condition, and causes a risk possibility of secondary accident. In this paper, we developed an active monitoring and approach alarm providing system using trail cameras and AIS for protection for the marine buoys. To do this, we analyzed existing researches and similar systems, extracted requirements for enhancement, and designed the system architecture that applied the enhanced elements. The main considerations of system enhancement are: integration of AIS and trail cameras, adopting of phased alarm technique by approaching ships, applying of selective communication module, conducting the image processing of ships for providing alarm, and applying thermal cameras. After that, we developed the system using designed architecture and verified effectiveness of the system based on laboratory or field-level tests.