• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.51-56
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• 2014

TETRA(TErrestrial Trunked RAdio) provide specialized disaster radio communication services as a standard European for digital TRS(Trunked Radio System). Especially, DMO(Direct Mode Operation) feature is used effectively in the radio shadow areas which base station does not propagate radio signal because it can communicate directly with terminal to terminal without base station's relay function. However, to effectively used DMO feature, radio coverage prediction information should be provided to users. Therefore in this paper, we were calculated link budget of TETRA DMO terminals which were distributing and operating in the country and then predicted reaching distance about radio propagation to be applied with path loss model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.4
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• pp.403-414
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• 1997

The distribution of the space debris caused by any source affects the DBS & FSS wave propagation for satellite communication. In this paper, the normalized expansion coefficients are evaluated with varying the volume distribution density of space debris and the operating frequency, and then the attenuation and phase shift are calculated by using the normalized expansion coefficients. Conclusively, the attenuation and phase shift are mostly affected with the real and imaginary part of the amplitude function, respectively, which represented by electric field component of the Bessel function. The results of this paper adapted for the design of the link budget for satellite communication system and the reconsideration of space environment as the space debris increses by geometric progression.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.889-895
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• 2010

In this paper, we have studied the implementation and adaptation of a smart antenna system for mobile terminals. We have designed a smart antenna system with switching beam structure in order to reduce the hardware and computational complexity. Additionally we have analyzed the reduction of the effect of multipath fading due to beamforming using real measurement data from commercial CDMA cellular channel environments. After analyzing the measurement data, we found out that the effect of fading reduces by ~3dB due to the effect of $2{\times}2$ beamforming in mobile terminals with 6dB beamforming gain.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.12
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• pp.55-64
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• 2018

The purpose of this study is to examine the status and limitations of the activation plan as a result of the change in urban regeneration paradigm. In particular, the change in housing life was considered following the guidelines of the New Deal project. Specifically, the three types - General Neighborhood, Housing Support, and DongneSaligi - were analyzed from the perspective of organization, space and program. In addition, the master plan and unit project, the organization and progress, and the budget plan were reviewed. As a result, the New Deal project for urban regeneration is importance on economic regeneration, which, unlike the integrated and continuous guide proposed by the government, could limit the individual progress of transitional organizations, 2-dimensional planing and various programs. Thus, first, in order to supplement the organization's verticality and inefficiency in progress, the annual business assessment should be discouraged and the permit and progress of the project should be determined at the local government level. Second, integrated and multidimensional planning is necessary to produce synergy effects in the physical environment. Finally, the link between program unit projects and the economic effects can be considered.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.197-203
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• 2016

In this paper, the dipole antenna that can control a beam steering were designed for attaching on LEO(Low Earth Orbit) small satellite. The proposed antenna was based on Yagi-Uda antenna. The parasitic element was proposed as a T-shape. Depending on the state of open or short at the end of a vertical element, we can choose a characteristic of the parasitic element with fixing a vertical element length of the parasitic element. Using this characteristic, we designed the director element and reflector element. The proposed antenna was designed to receive UHF 436.5 MHz. Antenna gain was chosen by link budget between one satellite and the other satellite or between the satellite and the ground station. By changing a vertical element length which is the largest variable that chooses an antenna characteristic, we confirmed that ${\lambda}/2$ length transformer has a result that improve 0.5 dB in comparison ${\lambda}/4$ length transformer from maximum gain direction. In production, we made an on/off switch composed of a diode, capacitor, and inductor control an open and short at the end of the parasitic element. As a result, the gain of antenna used in a link between one satellite and the other satellite had average 5.92 dBi. And the gain of antenna used in a link between the satellite and the ground station had average 0.99 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.868-882
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• 2009

In this paper, channel model and wireless link performance analysis for the short-range wireless communication system applications in the terahertz frequency which is currently interested in many countries will be described. In order to realize high data rates above 10 Gbps, the more wide bandwidths will be required than the currently available bandwidths of millimeter-wave frequencies, therefore, the carrier frequencies will be pushed to THz range to obtain larger bandwidths. From the THz atmospheric propagation characteristics based on ITU-R P.676-7, the available bandwidths were calculated to be 68, 48 and 45 GHz at the center frequencies of 220, 300 and 350 GHz, respectively. With these larger bandwidths, it was shown from the simulation that higher data rate above 10 Gbps can be achieved using lower order modulation schemes which have spectral efficiency of below 1. The indoor propagation delay spread characteristics were analyzed using a simplified PDP model with respect to building materials. The RMS delay spread was calculated to be 9.23 ns in a room size of $6\;m(L){\times}5\;m(W){\times}2.5\;m(H)$ for the concrete plaster with TE polarization, which is a similar result of below 10 ns from the Ray-Tracing simulation in the reference paper. The indoor wireless link performance analysis results showed that receiver sensitivity was $-56{\sim}-46\;dBm$ over bandwidth of $5{\sim}50\;GHz$ and antenna gain was calculated to be $26.6{\sim}31.6\;dBi$ at link distance of 10m under the BPSK modulation scheme. The maximum achievable data rates were estimated to be 30, 16 and 12 Gbps at the carrier frequencies of 220, 300 and 350 GHz, respectively, under the A WGN and LOS conditions, where it was assumed that the output power of the transmitter is -15 dBm and link distance of 1 m with BER of $10^{-12}$. If the output power of transmitter is increased, the more higher data rate can be achieved than the above results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1710-1714
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• 2010

The budget for the acquisition and R&D for the national defence systems has come out of tax payers' pockets. On the other hand, the weapon systems become more complex and thus the underlying costs tend to increase continuously. As such, the need for efficiently managing the budget has drastically increased. In accordance with this necessity, the Defence Acquisition Program Administration (DAPA) of Korea has issued the instruction No.65 dictating that systems engineering (SE) must be applied when weapon systems are acquired or developed in Korea. Specifically, a list of the products that should be generated from the acquisition programs is provided. The problem is that the unexperienced companies in the defence systems industry cannot easily know how to approach the new regulation. The purpose of this study is to devise a possible remedy to solve the problem. To do so, we first review the list of the products that are required by DAPA. Then, an appropriate systems engineering processes is studied for each product. Then, a necessary link between each product and SE process activity is identified and summarized. The result obtained may be useful as a stepping stone to develop more efficient method for the list of the products.

• Korean Journal of Construction Engineering and Management
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• v.8 no.4
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• pp.110-118
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• 2007

For deciding the owner's budget of the building construction in the predesign stage, the probabilistic methodologies for estimating the cost are often studied, however these parameter-based conceptual estimating methodology has limitation of applying it to the practical business because it hardly can link the design decision-making and the cost estimating and control. Besides if the result of detail estimating after detail design is over the budget, locally and arbitrarily control the level of interior design and fix the design. This research proposed the prototype-based cost estimating model for building interior construction which leads to estimate the interior cost easily linking with design decision-making and supports to evaluate the design alternatives in the schematic design and the design development stage for office buildings. The model divides the building on the design process by Element Breakdown Structure and presents the design alternative by selecting the elements of each room from the database accumulated the historical office buildings' prototypes and estimates the cost. The 2 case studies presented to validate the effectiveness of as the linking tool integrating the design and construction data and applicability to the practical design on the presented prototype-based model.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.19-32
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• 2014

This study evaluated economic value recognized by the residents for the pleasant urban park management using contingent valuation method(CVM) to APEC Memorial Park in Pusan in terms of private fund development for the management of the city park. As a result, the estimated amount payable by each household for the management of APEC Memorial Park in Busan was between 5,673 won and 8,358 won. If such amount is expanded to households in park hosting area, it was 2.2~2.3 times of the park management budget in 2012, which demonstrates the willingness to pay (WTP) of residents for pleasant park was higher than the management budget. Social factors of respondents affecting WTP for city park management operation included age, educational level and income level. Those with high age and high education level had higher WTP. And, WTP was much affected by the use of park and recognition of residents. In particular, those with high frequency in the use of parks had higher WTP, and the users with more than once per week had 1.1 times higher WTP than overall WTP. Then, the satisfaction of park rather than recognition of necessity of park had led to higher WTP. Accordingly, it is necessary to manage park facility management and use program operation to enhance park satisfaction and it is also required to develop a park culture distribution policy to link such recognition to donation.

• Korean Journal of Remote Sensing
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• v.34 no.6_2
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• pp.1193-1202
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• 2018

It is important to quantitatively analyze the energy budget for understanding of long-term climate change in Arctic. High-quality and long-term radiative parameters are needed to understand the energy budget. Since most of radiative flux components based on satellite are provide for a short period, several data must be used together. It is important to acquaint differences between data to link for conjunction with several data. In this study, we investigated the comparative analysis of Arctic radiative flux product such as CERES and GEWEX to provide basic information for data linkage and analysis of changes in Arctic climate. As a result, GEWEX was underestimated the radiative variables, and it difference between the two data was about $3{\sim}25W/m^2$. In addition, the difference in high-latitude and sea ice regions have increased. In case of comparing with monthly means, the other variables except for longwave downward flux represent high difference of $9.26{\sim}26.71W/m^2$ in spring-summer season. The results of this study can be used standard data for blending and selecting GEWEX and CERES radiative flux data due to recognition of characteristics according to ice-ocean area, season, and regions.