• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.349-358
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• 2015

The research and development trend of Trajectory-based Operations(TBO), which is considered as a key concept of future Air Traffic Management(ATM), is presented in this paper. The operational concepts of TBO in ASBU(Aviation System Block Upgrade) from ICAO(International Civil Aviation Organization) have been summarized, and the detailed operational concepts and procedures, which can be realized in the near future, are described through the investigations of operational concept development and related research/development activities of TBO in USA and Europe. The technical enablers, which have been identified based on understanding of TBO operational concepts, are introduced, and related research/development status of each technical enabler has been presented.

• Korean Medical Education Review
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• v.11 no.1
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• pp.21-33
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• 2009

The purpose of this study is to review a variety of e-learning use in medical education, and to analyze the e-learning related research in medical education, finally to discuss possibilities and limitations of e-learning in future. Subjects of this research are 46 papers published in Korean Medical Database, PubMed, MEDLIS, RISS4U. Content analysis of 46 papers have been conducted based on the period of research, research methods, research subjects, study personnel, effectiveness. The results are as follows. First, various e-learning, such as hyper-media, simulation-based medical education (SBME), game-based learning, web-based learning, computer-based test (CBT) are implemented in medical education. Second, 35 research (76.1%) has verified the positive effect of e-learning. Third, in the case of Korean studies, experimental studies (46.2%) in a short period (46.2%) of 50-100 people (42.3%) to take the most. As a result, it is reported a lack of theoretical discussion and insight on e-learning compared to foreign research. Educational paradigms are currently shifting from off-line to on-line, from traditional classroom lecture to e-learning. But e-learning is not a substitution to traditional teaching, but a matter of choice. The choice is up to medical professors and students.

• ETRI Journal
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• v.42 no.2
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• pp.272-281
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• 2020

Three-dimensional (3D) selfie services, one of the major 3D printing services, print 3D models of an individual's face via scanning. However, most of these services require expensive full-color supporting 3D printers. The high cost of such printers poses a challenge in launching a variety of 3D printing application services. This paper presents a stencil-based 3D facial relief creation method employing a low-cost RGBD sensor and a 3D printer. Stencil-based 3D facial relief is an artwork in which some parts are holes, similar to that in a stencil, and other parts stand out, as in a relief. The proposed method creates a new type of relief by combining the existing stencil techniques and relief techniques. As a result, the 3D printed product resembles a two-colored object rather than a one-colored object even when a monochrome 3D printer is used. Unlike existing personalization-based 3D printing services, the proposed method enables the printing and delivery of products to customers in a short period of time. Experimental results reveal that, compared to existing 3D selfie products printed by monochrome 3D printers, our products have a higher degree of similarity and are more profitable.

• ETRI Journal
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• v.46 no.2
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• pp.333-346
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• 2024

Various techniques for noninvasively focus microwave energy on lesions have been proposed for thermotherapy. To focus the microwave energy on the lesion, a focusing parameter, which is referred to as the magnitude and phase of microwaves radiated from an external array antenna, is very important. Although the finite-difference time-domain (FDTD)-based time-reversal (TR) focusing algorithm is widely used, it has a long processing time if the focusing target position changes or if optimization is needed. We propose a technique to obtain multistatic data (MSD) based on Green's function and use it to derive the focusing parameters. Computer simulations were used to evaluate the electric fields inside the object using the FDTD method and Green's function as well as to compare the focusing parameters using FDTD- and MSD-based TR focusing algorithms. Regardless of the use of Green's function, the processing time of MSD-based TR focusing algorithms reduces to approximately 1/2 or 1/590 compared with the FDTD-based algorithm. In addition, we optimize the focusing parameters to eliminate hotspots, which are unnecessary focusing positions, by adding phase-reversed electric fields and confirm hotspot suppression through simulations.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.249-252
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• 2005

In this paper, we propose a Digital Living Network Alliance (DLNA) proxy system, to provide services for accessing and sharing various DLNA-based media contents which are distributed over his/her or other's home facilities via home network or internet. The proposed system based on DLNA[1] and SIP Notification mechanism[2] so that data such as contents can be transferred from home network consisted with private IP from outside public IP networks.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.459-460
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• 2006

In this paper we introduce the implementation of PC-based receiver platform to verify T-DMB middleware APIs. Recently, generic APIs in T-DMB middleware (called DMB MATE API) have been designed to enable inter-operable applications to be downloaded from both the broadcast and telecommunication networks in advance and to be executed on T-DMB receivers from any manufacturers. We also verify the designed MATE API through execution of several applications at the PC-based receiver. In future, the T-DMB middleware verified in PC can be implemented at various receivers such as T-DMB phone and portable T-DMB receiver.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.402-410
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• 2017

Acoustic based localization is essential to operate autonomous robotic systems in underwater environment where the use of sensorial data is limited. This paper proposes a localization method using artificial underwater acoustic sources. The proposed method acquires directional angles of acoustic sources using time difference of arrivals of two hydrophones. For this purpose, a probabilistic approach is used for accurate estimation of the time delay. Then, Gaussian sum filter based SLAM technique is used to localize both acoustic sources and underwater vehicle. It is performed by using bearing of acoustic sources as measurement and inertial sensors as prediction model. The proposed method can handle directional ambiguity of time difference based source localization by generating Gaussian models corresponding to possible locations of both front and back sides. Through these processes, the proposed method can provide reliable localization method for underwater vehicles without any prior information of source locations. The performance of the proposed method is verified by experimental results conducted in a real sea environment.

• ETRI Journal
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• v.45 no.4
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• pp.636-649
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• 2023

Renewable energy generation cannot be consistently predicted or controlled. Therefore, it is currently not widely used in the electricity market, which requires dependable production. In this study, reliability- and variance-based controls of energy storage strategies are proposed to utilize renewable energy as a steady contributor to the electricity market. For reliability-based control, photovoltaic (PV) generation is assumed to be registered in the power generation plan. PV generation yields a reliable output using energy storage units to compensate for PV prediction errors. We also propose a runtime state-ofcharge management method for sustainable operations. With variance-based controls, changes in rapid power generation are limited through ramp rate control. This study introduces new reliability and variance indices as indicators for evaluating these strategies. The reliability index quantifies the degree to which the actual generation realizes the plan, and the variance index quantifies the degree of power change. The two strategies are verified based on simulations and experiments. The reliability index improved by 3.1 times on average over 21 days at a real power plant.

• ETRI Journal
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• v.25 no.6
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• pp.527-530
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• 2003

In this study, we consider distance-based registration (DBR) and propose a DBR with implicit registration (DBIR) in order to improve the performance of the DBR. With analytical models based on a 2-dimensional random walk in a hexagonal cell configuration, we analyzed the performance of the DBR and DBIR. Our results showed that the DBIR always outperforms the DBR.

• ETRI Journal
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• v.29 no.4
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• pp.527-529
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• 2007

In this paper, a decision-tree-based Markov model for phrase break prediction is proposed. The model takes advantage of the non-homogeneous-features-based classification ability of decision tree and temporal break sequence modeling based on the Markov process. For this experiment, a text corpus tagged with parts-of-speech and three break strength levels is prepared and evaluated. The complex feature set, textual conditions, and prior knowledge are utilized; and chunking rules are applied to the search results. The proposed model shows an error reduction rate of about 11.6% compared to the conventional classification model.