• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.561-569
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• 2008

Currently, satellite image, aerial image and airborne laser scanning data are mostly used to build 3D image models. However, we are in need of quality 3D image models as current models cannot express topographic and features most elaborately and realistically. When making 3D image models, the model is first built and textures from terrestrial photos are applied to add realistic features to the model. This study analyzed techniques to use photogrammetry and laser scanning data to create a 3D image models with topography, building and statue that emphasize spatial accuracy, delicate depiction and photo-realistic imaging. 3D image models with spatial accuracy and photographic texture were built to be served via 3D image map services systems on the internet. The 3D image models can be used for various purposes, such as daylight and view right analysis, landscape analysis, facility management system.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.55-63
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• 2019

Recently, the use of real-world image data has been increasing to express realistic virtual environments in various application fields such as education, manufacturing, and construction. In particular, with increasing interest in digital twins like smart cities, realistic 3D urban models are being built using real-world images, such as aerial images. However, the captured aerial image includes shadows from the sun, and the 3D city model including the shadows has a problem of distorting and expressing information to the user. Many studies have been conducted to remove the shadow, but it is recognized as a challenging problem that is still difficult to solve. In this paper, we construct a virtual environment dataset including the height map of buildings using 3D spatial information provided by VWorld, and We propose a new shadow detection method using height map and deep learning. According to the experimental results, We can observed that the shadow detection error rate is reduced when using the height map.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.281-288
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• 2014

QR code (abbreviated from Quick Response Code) is code system that is strong in against to apply image processing techniques (skew, warp, blur, and rotate) as QR codes can store several hundred times the amount of information carried by ordinary bar codes. For this reason, QR code is used in various fields, e.g., air ticket (boarding control system), food(vegetables, meat etc.) tracking system, contact lenses management, prescription management, patient wrist band (patient management) etc. In this paper, we proposed reversible data hiding for binary images. A reversible data hiding algorithm, which can recover the original image without any distortion from the marked (stego) image after the hidden data have been extracted, because it is possible to use various kinds of purposes. QR code can be used to generate by anyone so it can be easily used for crime. In order to prevent crimes related QR code, reversible data hiding can confirm if QR code is counterfeit or not as including authentication information. In this paper, we proved proposed method as experiments.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.221-230
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• 2020

The effects-based operation, which would reduce unnecessary efforts and meaningless sacrifices incurred during a war and simultaneously reach the will of the enemy leadership by strategic attacks, was discarded for the reason that it was difficult to apply it to military power except for airpower. However, cyberspace, which can be thoroughly logical and calculated, can be suitable for conducting effects-based operations. This study examined a way to carry out effects-based operations in such cyberspaces. It laid the foundation for overcoming the limitations of effects-based operations revealed in previous battle cases and executing the operations in cyber battlespace where the boundary between physical and cyberspaces gradually disappeared. Futhermore, it demonstrated that effects-based operations could be carried out in cyberspace by establishing a military strategy, which could conduct the operations through an analysis of previous cyber-attack cases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.1-9
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• 2012

In this paper, we presents the modeling and implementation of the DDS(Direct Digital synthesizer) driven offset PLL(Pghase Locked Loop) with DAC(Digital Analog Converter) for coarse tune. The PLL synthesizer was designed for minimizing the size and offset frequency and DDS technique was used for ultra low noise and fast lock up time, also DAC was used for coarse tune. The output phase noise was analyzed by superposition theory with the phase noise transfer function and noise source modeling. the phase noise prediction was evaluated by comparing with the measured data. The designed synthesizer has ultra fast lock time within 6 usec and ultra low phase noise performance of -120 dBc/Hz at 10KHz offset frequency.

• Journal of Internet Computing and Services
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• v.13 no.5
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• pp.21-31
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• 2012

Threat Evaluation(TE) which has air intelligence attained by identifying friend or foe evaluates the target's threat degree, so it provides information to Weapon Assignment(WA) step. Most of TE data are passed by sensor measured values, but existing techniques(fuzzy, bayesian network, and so on) have many weaknesses that erroneous linkages and missing data may fall into confusion in decision making. Therefore we need to efficient Threat Evaluation system that can refine various sensor data's linkages and calculate reliable threat values under unpredictable war situations. In this paper, we suggest new threat evaluation system based on information fusion JDL model, and it is principle that combine fuzzy which is favorable to refine ambiguous relationships with bayesian network useful to inference battled situation having insufficient evidence and to use learning algorithm. Finally, the system's performance by getting threat evaluation on an air defense scenario is presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.97-104
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• 2018

In the conventional direction finding, the antenna is installed at a high position on the ground to detect the position of the target with the environment of the LOS(Line of Sight) as much as the signal receiving environment. However, in order to configure such environment, high cost and installation time were required. In this paper, we use TDOA(Time Difference of Arrival) technique to utilize drones in direction finding, so that four drones can be used for directions finding simulation. Simulations based on drone and TDOA direction finding were constructed using additional signal processing Taylor series and Exact Interactive Algorithm. In the simulation, the receiving power is defined by using the 800MHz path-loss model using the GPS information of the ground direction detection, and the position estimation performance is analyzed when the TDOA technique, the Taylor series, and the Exact Interactive Alogrithm are applied.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.1-11
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• 2019

Today's software systems are becoming larger and more complicated, and the risk of accidents and failures have also grown larger. Software failures and accidents in industrial fields such as automobiles, nuclear power plants, railroad industries, etc. may lead to severe damage of property and human life. The safety-related international standards, such as IEC 61508 have been established and applied to industries for decades. The safety life cycle specified in the standards emphasize the activities to develop safety requirements through hazard and risk analysis in the early stage of software development. In this paper, we propose 'Hazard Analysis Process based on STPA using SysML' in order to ensure the safety of software at the early stage of software development. The proposed hazard analysis can be effectively performed minimizing the loss of hazard by using the BDD and the IBD of SysML to define the control structure of a system. The proposed method also improves the specification of the safety constraints(requirement) by using SD. As a result, it is possible to identify the hazard without missing and identify the hazard scenarios in detail, and safety can be sufficiently ensured in the early stage of software development.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.107-115
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• 2019

Effective construction safety management systems are desperately required for reducing damage caused by increasing safety accidents in construction sites. Safety accidents in construction sites can effectively protect if proactive measures are taken to prevent unauthorized worker access the expected hazardous area. In this study, we have developed a IoT(Internet of Things)-based dangerous zone alarming system for safety management in construction sites, which can be operated at low cost in large-scale sites as well as small and medium-sized construction sites. The development system utilizes a Zigbee-based beacon technology and cellular mobile communication technology to detect when authorized workers, unauthorized field workers or outsiders approaches hazardous zones. If somebody approaches the dangerous zones the system notifies immediately to the safety manager with a danger warning signal. It is expected that this system can effectively prevent safety accidents when applied to construction sites.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.113-124
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• 2022

In wartime conditions, the communication system of military aircraft is exposed to jamming, and it is necessary to mount communication equipment with high anti-jamming performance in order to perform air operations smoothly even in an environment where jamming attempts are made. In this paper, we check in detail the jamming and anti-jamming technology that can be applied to wireless communication, and the data disclosed on the difference in specifications of the next-generation anti-jamming radio with frequency hopping method and the improvement of anti-jamming performance according to these changes. It was briefly analyzed within the scope. In addition, the points to be considered when designing a new domestic aircraft and the possibility of installing the next-generation anti-jamming communication equipment on the currently operating aircraft were confirmed, and the tactical usefulness of improving the anti-jamming capability of the next-generation anti-jamming communication equipment was confirmed.