• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.661-668
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• 2004

A novel method to reject the spurious signals which are occurred at Weaver-type low-IF transmitter was proposed in this paper. The spurious signals are generated by the gain and phase imbalances of I/Q channel or imperfect characteristics of 90$^{\circ}$ phase shifter in local oscillator for I/Q channel source. By deriving the gain and phase-based functions from RF spurious signal with the channel imbalance information, the lie channel imbalances were deduced as functions with magnitude and sign dependent on I/Q channel imbalance degree. The proposed method compensates the estimated I/Q channel imbalances by correlation values between the down-converted signal obtained by squaring the output signal itself using a simple mixer and the modified baseband signal. By comparing two signals after A/D conversion, the magnitude and sign of each type of imbalances can be determined separately and simultaneously. Based on the I/Q channel imbalance compensation, the spurious signals can be reduced by adjusting the gain and phase values of I or Q channel signal. The way to estimate the channel imbalances of the up-conversion mixer was presented and verified by using theoretical derivations and computer simulations.

• The Korean Journal of Archival Studies
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• no.45
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• pp.51-82
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• 2015

Maeul-making, which is to restore inherent characteristics of maeul as a living community has been proceeded by local communities themselves since the 1990s when political democracy and local government in Korean society has been progressed in full-scale. Although New Maeul Movement has been done in the 1970s before and after, it is different from maeul-making because it was focused mainly on improving physical environments of rural communities and initiated by government. The development of maeul community archives in Korea has been related closely to such a maeul-making since the 1990s. Maeul-based community archives, maeul community archives had been begun to build as part of maeul-making and grass-root movement by the 2000s. Initiated by self-motivated communities, maeul community archives were carried out through cooperations between civic activists and residents in maeul communities and voluntary professional archivists from outside. Although records about the maeul community has been collected by mainstream cultural institutions such as public archives, museum, local historical association, and local cultural center, it was at this time to collect records of the maeul community by self-motivated local residents. This tendency of 'independent' maeul community archives, however, is currently entering upon a new phase with the city of Seoul's project (2012) to support making a maeul community, that is, the governance phase based on private-government partnership. At this point of time, it is important for maeul community archives to be built on privately-led governance model that guarantees their autonomy and at the same time bring government's knowhow and supports into them, as opposed to the way captured or driven unilaterally by government. This article explores the growth of maeul community archives and collections in Korean society through a range of self-motivated bodies; the interaction with government; and as a result of those interactions, the creation of maeul community archives based on governance. To introduce and explicate the motivations behind maeul archiving endeavors, this article will first sketch something of the historical, social, and political context in which 'maeul' communities have arisen, collapsed, and restored. It will then examine in more detail some specific examples of maeul community archives as grass-root movement of maeul community. The third section will attempt to identify the governance model of maeul community archives under the auspices of the city of Seoul and its limitations. Finally through these activities, it will suggest the ways in which maeul community archives commit themselves to their duty of grass-root movement of community and at the same time, secure sustainability, that is, concrete ways of privately initiated governance model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.3116-3133
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• 2020

Based on the teleportation by quantum walk, a quantum secret sharing scheme with credible authentication is proposed. Using the Hash function and quantum local operation, combined with the two-step quantum walks circuit on the line, the identity authentication and the teleportation of the secret information in distribution phase are realized. Participants collaborate honestly to recover secret information based on particle measurement results, preventing untrusted agents and external attacks from obtaining useful information. Due to the application of quantum walk, the sender does not need to prepare the necessary entangled state in advance, simply encodes the information to be sent in the coin state, and applies the conditional shift operator between the coin space and the position space to produce the entangled state necessary for quantum teleportation. Security analysis shows that the protocol can effectively resist intercept/resend attacks, entanglement attacks, participant attacks, and impersonation attacks. In addition, the quantum walk circuit used has been implemented in many different physical systems and experiments, so this quantum secret sharing scheme may be achievable in the future.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1318-1321
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• 1997

A method for two-dimensional position measurement using an enclosing field has been studied and reported. The feature of this mehtod is zooming functional measurement by operating both the initial phase shift and the brightness ratio of the lighting function. An experimental system was developed and the experimental results on zooming effects are shown in this paper. This system is also an example of a "progressive learning measurement system".tem".uot;.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.980-986
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• 2012

In this paper we develop a minimalist model of single molecule spectroscopy in a dynamic environment. Our model is based upon a lattice system consisting of a probe molecule embedded in an Ising-model like environment. We assume that the probe molecule interacts with the Ising spins via a dipole-dipole potential, and calculate free energy curves and lineshapes of the system. To investigate fluctuation behavior of the system we exploit the metadynamics sampling method. In particular, using the method, we calculate the free energy curve of magnetization of the lattice and that of the transition energy of the probe molecule. Furthermore, we compare efficiencies of three different sampling methods used; unbiased, umbrella, and metadynamics sampling methods. Finally, we explore the lineshape behavior of the probe molecule as the system undergoes a phase transition from a sub-critical and to a super-critical temperature. We show that the transition energy of a probe molecule is broadly distributed due to the heterogeneous, local environments.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.285-291
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• 2005

In this paper, the author proposes a fatigue damage parameter of spot welded joints under proportional loading. The proposed fatigue damage parameter is developed based on von Mises' equivalent stress and local structural stress at the edge of spot weld nugget. The structural stress at the edges of the weld nugget in each sheet is calculated using the forces and moments that are determined by finite element analysis. A structural equivalent stress is then calculated by von Mises' equivalent stress equation. The structural equivalent stresses are correlated to experimental fatigue life of the spot welded joints. The proposed parameter is evaluated with fatigue test data of spot welds subjected to multi axial and tensile-shear loads. Sheppard's parameter and Rupp and co-workers' parameter are also evaluated with the same test data to compare with the author's parameter. This proposed parameter presents a better correlation with experimental fatigue data than those of Sheppard's and Rupp and co-workers' parameter. The proposed parameter should be very effective for durability calculations during the early design phase since coarsely meshed finite element models can be employed.

• Journal of the military operations research society of Korea
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• v.2 no.1
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• pp.185-194
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• 1976

A terminal response time analysis for a general class of terminals-to-computer subsystem is presented in this paper. On the point of the front view, it should be considered for R.O.K. Military Defense to set up the communication network in order to facilitate for the currency of the information and the data communication system. The model used to study is based on the advanced data communications system in which terminals are connected to Terminal Control Units(TCU) that are in turn connected to local Front-End Processor(FEP). The line control procedures used to interface a TCU and an FEP may be half-duplex Binary Synchronous Communication(BSC), half-duplex Synchronous Data Link Control(SDLC), or full-duplex SLDC. This paper will contribute to facilitate the initial phase of system design and configuration for the Military Defense Communication Network System in future.

• 한국정보교육학회:학술대회논문집
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• 2010.08a
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• pp.221-226
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• 2010

Culture is like living organisms based on local and history. Therefore, we don't understand the whole phase of the culture if we neglect the information of the time and space. In this paper, we describe a preliminary study building of a 3D electronic cultural atlas about the national education center for Korean traditional music.

• International Journal of Contents
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• v.5 no.2
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• pp.59-63
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• 2009

Since it is hard to use GPS for tracking mobile user in indoor environments, much research has focused on techniques using existing wireless local area network infrastructure. Signal strength received at a fixed location is not constant, so fingerprinting approach which use pattern matching is popular. But this approach has to pay additional costs to determine user location. This paper proposes a new approach to find user's location efficiently using an index scheme. After analyzing characteristics of RF signals, the paper suggests the data processing method how the signal strength values for each of the access points are recorded in a radio map. To reduce computational cost during the location determination phase, multidimensional indexes for radio map with the important information which is the order of the strongest access points are used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.231-233
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• 2001

Axial magnetic field(AMF) type electrodes can be increase the interrupting capability of vacuum interrupters. Depending on the design, the principle of the local axial magnetic field arrangement are different. In this paper, a new AMF contact design based on a unipolar field arrangement and its characteristics are introduced. The influence of the unipolar AMF on the arc behavior is described by high-speed video camera. In addition, three-dimensional AMF simulations have been peformed by means of a finite element analysis(FEM) program to analyze the influence of magnetic field distribution on the AMF performance. The high interrupting capability of the unipolar AMF type electrode has been confirmed by three-phase test.