• The Journal of Engineering Research
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• v.5 no.1
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• pp.5-16
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• 2004

In the era which computer communication changes from auxiliary means of communication to main means of communication, the messenger system becomes the leader of communication. The multi messenger implemented in this paper used .NET and strong MFC as a language of next generation to put n higher competitiveness than current another messenger systems. In addition, it included face to face chatting function as well as messenger function.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.52.4-52.4
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• 2021

The 7-dimensional Telescope (7DT) is an innovative multiple telescope system that can perform a rapid identification of optical counterparts of gravitational-wave (GW) sources and a wide variety of other astronomical projects. This telescope is being developed as a part of the recently approved National Challenge program, the GW Universe project, with a full operation planned at the end of 2023. The word 7-dimension stands for x, y, z positions, the radial velocity, the time, the wavelength, and the flux of astronomical sources, implying the telescope's capability of performing time-series wide-field, IFU-type spectroscopic observations. The 7DT is composed of about twenty 0.5-m wide-field telescopes, and it can obtain spectral-imaging data at 40 different wavelengths to the depth of 20 AB mag with 3 min exposure for a given epoch. In this talk, we will introduce the telescope system, and outline its scientific capabilities with an emphasis on multi-messenger astronomy and a few other key science topics.

• (The)Study of the Eastern Classic
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• no.69
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• pp.419-450
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• 2017

This study aims to discover the clue of the current modern postal system development by looking at the delivery patterns of Korean letters during the Joseon Dynasty. A letter is a text medium that the sender sends to a recipient by sending a message of news. The form and contents of the letter are influenced by the various surrounding factors and are adapted to circumstances. The study aims to clear up the method of delivery and the nature of the transmitter among the environmental factors which affects the format and contents of Korean letters. Depending on the public or private matters, the delivery method is divided into a public agency and a private messenger, or divided into one-phase delivery and the multi-phase delivery depending on whether or not a phase is divided into stages. It is also divided into a one-way and a round-transmission depending on whether or not it is round-switched. The transmitter is divided into a verbal communication, the letter and verbal communication, and the letter communication according to whether or not it is by verbal, and divided into the relational and the non-relational person according to the relationship with the sender. Also depending on whether the transmitter is exclusive or not, it is divided into the exclusive messenger and the messenger who deliver a letter incidentally while come and go. In the aspect of the delivery method, We can see the possibility of developing to a modern mail system through the public method, the multi-phase delivery, one-way delivery and in the aspect of the transmitter, we can see the possibility through the letter delivery, non-related transmitter, and the exclusive messenger.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.431-436
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• 2009

As the telecommunication lines bring into widespread use, one of the most important aspects related to power distribution systems is effectively to evaluate the effect on the telecommunication lines from power lines. One of the efficient methods to evaluate the effect is to measure the induced voltage of a telecommunication line as a result of a ground-loop. If the power lines cause high induced voltage, the ground reference in the telecommunication lines is no longer a stable potential, so signals may ride on the noise. A ground loop is common wiring conditions where a ground current may take more than one path to return to the grounding electrode at the arrangement between the power lines and telecommunication lines. When a multi-path connection between the power lines and telecommunication line circuits exists, the resulting arrangement is known as a ground loop. Whenever a ground loop exists, there are potential for damages or abnormal operations of the telecommunication lines. The power lines can induce the voltage on the communication line. The effects can be calculated by considering the inductances and capacitances. However, if we assume that there are only power lines, it doesn't have a practical meaning because there are conductors with other purpose in the neighborhood of the lines. If we consider that case, we need more complex system. Therefore we suggest more complex system considering the conductors with other purpose in the neighborhood of the lines. The neutral wires and the overhead ground wires are considered for calculating the induced voltage. We assume that there are the messenger wires beside the power line as a result of increased use of them. The main purpose of this paper is a study on a shielding effect of messenger wires in the distribution lines. EMTP(Electro-Magnetic Transients Program) program is used for the induced voltage calculation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1711-1716
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• 2018

Unlike conventional transmission and distribution lines, catenary system for operating electric railway vehicles are composed of multi-conductor groups (feeder line, contact wire, messenger wire, protection wire) and are used for railway employees, public or passengers in the station yards. Electric shock hazards are exposed and electric shocks such as death or serious injury are occurring in electric railway vehicles, railway high-voltage distribution lines, and catenary system. In order to analyze the types of electric shock accidents on railway by systematic approach method, we modeled 'unsafe behavior classification' method using swiss cheese model. Based on this method, we derived the type of electric shock accidents about railway accidents during the last 5 years by analyzing the frequency of occurrence of human errors and unsafe acts, laws and regulations related to violations, and so on.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.62.3-62.3
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• 2019

After first identification of electromagnetic counterpart of gravitational wave source (GW170817), era of multi-messenger astronomy has begun. For specifying coordinate, magnitude, and host galaxy information, optical follow-up observation of GW source becomes important. With following engineering run and O3 run of LIGO and VIRGO starting in March 2019, we present searching strategy for optical counterpart of GW source using KMTNet. 24 hours monitoring system and large field of view (4 square-degree) of KMTNet are advantage to discover a transient like GW event. By performing tiling observation of high probability area in GW localization map, we expect to observe early light-curve of GW optical counterpart. After identification, follow-up observation with various KMTNet bands and other telescopes like Gemini and UKIRT will also be performed. We will study collision mechanism, progenitor, and characteristics of host galaxy using observation data of GW source.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.61.2-61.2
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• 2019

A total of 10,317 hours of the KMTNet telescope time were allocated for the predefined science programs, and 7,765 hours have been used for science exposures in Chile, Australia and South Africa last year. The success rate of science observation has increased from 70.7% to 75.3%, and the system operation rate has also increased from 97.6% to 99.6%. There were many improvements in mechanical parts of the dome structure and telescope system, and newly installed filter driers of the CCD camera increased the stability of the system by preventing contamination of oil in the gas line in advance. In order to prepare for the time domain astronomy and multi messenger astronomy era, a pilot program was designed and is now being tested. It targets for fast follow-up observations of optical transient events, however it runs during twilight times only so it does not interrupt any granted science program. A total of 32 SCI papers were published using the system in 2018 and it is a good indication of the high science performance of KMTNet. The selection process of the next observation programs starting from October 2020 and its timeline will be discussed in this meeting.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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• pp.859-876
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• 2010

In this paper, we propose a hierarchical application traffic classification system as an alternative means to overcome the limitations of the port number and payload based methodologies, which are traditionally considered traffic classification methods. The proposed system is a new classification model that hierarchically combines a binary classifier SVM and Support Vector Data Descriptions (SVDDs). The proposed system selects an optimal attribute subset from the bi-directional traffic flows generated by our traffic analysis system (KU-MON) that enables real-time collection and analysis of campus traffic. The system is composed of three layers: The first layer is a binary classifier SVM that performs rapid classification between P2P and non-P2P traffic. The second layer classifies P2P traffic into file-sharing, messenger and TV, based on three SVDDs. The third layer performs specialized classification of all individual application traffic types. Since the proposed system enables both coarse- and fine-grained classification, it can guarantee efficient resource management, such as a stable network environment, seamless bandwidth guarantee and appropriate QoS. Moreover, even when a new application emerges, it can be easily adapted for incremental updating and scaling. Only additional training for the new part of the application traffic is needed instead of retraining the entire system. The performance of the proposed system is validated via experiments which confirm that its recall and precision measures are satisfactory.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2007.02a
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• pp.41-44
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• 2007

최근 유비쿼터스 환경이 도래함에 따라, 모바일 장비의 이용이 급격하게 증가하였다. 또한 이러한 모바일 장비와 더불어 각종 모바일 기반의 서비스 들이 나타나고 있다. 특히, 모바일 기반의 대표적인 서비스 중에서 메신저 서비스는 다중사용자간의 대화, 파일 전송, 위치 추적 등의 다양한 서비스를 제공한다. 그러나 이러한 메신저 서비스의 수가 증가함에 따라, 사용자에게 선택의 어려움을 줄 수 있다. 또한, 이러한 각각의 메신저 벤더간의 프로토콜이 다르므로, 메신저간의 통합이 어렵다. 따라서 본 논문에서는 이기종 메신저간의 통합을 위한 에이전트 기반의 모바일 메신저 서비스의 아키텍처를 소개한다. 제안하는 메신저 서비스는 멀티 에이전트로 구성되며, 각각의 메신저 서비스의 사용자를 에이전트화 하여 에이전트간의 협업과 통신을 통한 메시지 송, 수신 및 파일 전송 등의 다양한 기능을 수행한다. 또한 제안하는 메신저 서비스는 에이전트 표준인 FIPA-ACL통신 규약을 준수함으로써, 에이전트 기반의 이기종 메신저 서비스와의 통신을 통한 통합 프레임워크를 제공한다.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.643-658
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• 2018

In this paper, we introduce a new framework for running the finite element (FE) packages inside an online Loop together with MATLAB. Contrary to the Hardware-in-the-Loop techniques (HiL), in the proposed Software-in-the-Loop framework (SiL), the FE package represents a simulation platform replicating the real system which can be out of access due to several strategic reasons, e.g., costs and accessibility. Practically, SiL for sophisticated structural design and multi-physical simulations provides a platform for preliminary tests before prototyping and mass production. This feature may reduce the new product's costs significantly and may add several flexibilities in implementing different instruments with the goal of shortlisting the most cost-effective ones before moving to real-time experiments for the civil and mechanical systems. The proposed SiL interconnection is not limited to ABAQUS as long as the host FE package is capable of executing user-defined commands in FORTRAN language. The focal point of this research is on using the compiled FORTRAN subroutine as a messenger between ABAQUS/CAE kernel and MATLAB Engine. In order to show the generality of the proposed scheme, the limitations of the available SiL schemes in the literature are addressed in this paper. Additionally, all technical details for establishing the connection between FEM and MATLAB are provided for the interested reader. Finally, two numerical sub-problems are defined for offline and online post-processing, i.e., offline optimization and closed-loop system performance analysis in control theory.