• Journal of the Korean Statistical Society
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• v.32 no.4
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• pp.411-423
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• 2003

In this paper we develop a method for calculating a probability that a particular generalized variance is the smallest of all the K multivariate normal generalized variances. The method gives a way of comparing K multivariate populations in terms of their dispersion or spread, because the generalized variance is a scalar measure of the overall multivariate scatter. Fully parametric frequentist approach for the probability is intractable and thus a Bayesian method is pursued using a variant of weighted Monte Carlo (WMC) sampling based approach. Necessary theory involved in the method and computation is provided.

• Journal of the military operations research society of Korea
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• v.29 no.2
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• pp.26-44
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• 2003

This study Is to forecast the damage of smallpox as a biological weapon and to measure the effect of potential responses (quarantine, vaccination and cure) to the spread of smallpox infection when a smallpox bioterrorism attack occurs. We designed the smallpox spreading simulation model through the literature study on a basis of some existing infectious disease models such as SIR, SEIR model by using Vensim program. In order to evaluate the performance of responses to smallpox, we measure the total infection population, infection sustaining duration, average infection rate and the infection spreading behavior of the smallpox. This study can help those who are related to the bioterrorism forecast the present and possible demage, and take more effective actions for minimizing the damage by smallpox bioterrorism.

• Knowledge Management Research
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• v.21 no.2
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• pp.1-19
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• 2020

The purpose of this study is to suggest a practical way to measure and report corporate social performance as public interest in corporate social value pursuits increases. In particular, we will look for ways to measure and report on the financial and social performance of a company based on the concept of the Double Bottom Line (DBL), which has recently spread to big companies. For this purpose, this study analyzed the theoretical background and practical techniques related to measuring and reporting corporate social performance, and examined methods for measuring and reporting social performance in the existing financial performance measurement system. As a result, SROI was the most suitable method for measuring social performance of a company. It is recommended that social performance reporting follows the disclosure method of the accounting system, and the details of reporting suggest that using the standard of GRI Standard, an international standard related to sustainability reporting, is the most reasonable alternative to 'Double Bottom Line' performance reporting.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.305-309
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• 2007

We live in high level of knowledge and information society spread of computer and rapid expansion of internet. Computer crime is various, complicated and inscrutable. we call it cybercrime. Therefore we should draw up a preventive device of the high-technology industry drain. This study is focused on the legal trend of preventive measure on the high-technology industry drain.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.328-334
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• 2024

The activation method of metallic foils is an important technique to measure the flux and energy of proton beams. In this paper, the method was used to measure the CSNS APEP proton flux at seven nominal proton energies ranging from 10 MeV to 70 MeV for beam spot sizes of the 20 mm × 20 mm and 50 mm × 50 mm. The reactions of ^natTi(p, x)⁴⁸V, ^natNi(p, x)⁵⁷Ni, ^natCu(p, x)⁵⁸Co, and ²⁷Al(p, x)²⁴Na were employed to measure the proton beam flux with a range of 10⁷-10⁹ p/cm²/s. Furthermore, we also proposed a method using the activity ratio with a stacked-foil target to determine the energy spread of a Gaussian-like distribution for different nominal proton energies. The optimal combinations of Al, Cu, Ti, Ni, Mo, Fe, Nb, and In foils were adopted for the proton energies. The measured energy spreads for degraded beams of 30 MeV-70 MeV were found to be smaller than 10.00%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.88-94
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• 2007

This paper deals with the performance analysis of 3-dimensional array antenna by DOA estimation and beamforming in GPS receiver for performance improvement by interference elimination. The array antenna in GPS receiver can improve the system performance by estimating DOA of arriving signal direction, making the main beam for desired direction and elimate the jammer signal by nulling while keeping the GPS signal direction by spatial filtering. In this paper, we propose five types of 3-dimensional array antenna and analyze the estimation error via MUSIC algorithm which is used for the estimation of DOA of arrived signal and beamforming performance. In analyzing DOA performance, we measure DOA estimation error, while in analyzing beamformig performance, we measure BER. In beamforming performance analyzing, we use various jammer power and the existence of GPS signal and angle spread. By performing through the computer simulation, Curved (B) 7-element antenna in proposed 3-dimensional array antenna exhibits the superior performance in the DOA estimation, estimation error, BER characteristic and angle spread compared to the rest four array antenna types.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.199-208
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• 2022

The world health organization classified the emerging coronavirus (known as Covid-19) as a pandemic after confirming the extent of spread and scale. As a matter of fact, outbreaks of similar scale or even worse have been witnessed throughout history. Thus, the development of prevention strategies exists to protect against such calamaties. One of the widely proven measures that controls the spread of any contagious diseases is social distancing. As a result, this paper will demonstrate the concept of an application "Be Aware" on enabling the implementation of this preventive measure. In particular "Be aware" evaluates the extent of congestion in public places using current time data. The proposed project will use Global Positioning System (GPS), and Application Programming Interface (API), to ensure information accuracy, and the API use Crowdsourcing to collect Real-Time Data (RTD) from the selected places. One line

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.92-99
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• 2001

To measure temporal variability of long- range transmission in northern part of the East Sea of Korea, low frequency acoustic sources were deployed on the continental shelf 0.4km south of Cape Shultz near the port of Vladivostok during October 1999. The transmissions of the phase modulated signals were recorded by VLA moored on the northern slope of Ulleung-do. The measured signals were processed for the acoustic arrivals and their variability in time. The temporal signal processing involves pulse compression of the phase-encoded signal, time spread and temporal coherence processing. Variability of the ocean sound speed field in time scales of short period seems to be dominated by random fluctuations caused by sound speed perturbation due to the vertical displacements associated with internal waves.

• Journal of Navigation and Port Research
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• v.44 no.5
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• pp.414-422
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• 2020

In this study, an empirical analysis of 55 ship finance cases executed by a specific ship finance bank from 2009 to 2016 during the recession period was conducted. The purpose of this study was to find the factors affecting changes in the debt performance of Korean shipping companies. The main factors were the loan nature (investment purpose, loan-to-value (LTV), syndicated loans, loan terms, put-option, balloon, and spread), financial nature (total assets turnover, net profit-to-sales ratio, debt ratio, quick ratio, total borrowing, bonds payable to total assets, interest expenses-to-sales ratio, debt service coverage ratio (DSCR), and total assets), and the company nature (company age, chief executive officer's (CEO's) shares, and listing status). In this study, the factors affecting the debt repayment capability of domestic shipping companies (loan nature, financial nature, and company nature) were verified. The credit rating was used to measure the dependent variable, debt repayment ability. The variables of investment purpose, put-option, balloon, and spread in the loan nature, debt ratio in the financial nature, and the CEO's shares and company age in the company nature were found to be significant.

• ETRI Journal
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• v.34 no.6
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• pp.911-921
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• 2012

In high-speed wireless communications, an analysis of the propagation characteristics is an important process. Information on the propagation characteristics suitable for each environment significantly helps in the design of mobile communications. This paper presents the analysis results of radio propagation characteristics in outdoor environments for a new mobile wireless system at 781 MHz. To avoid the interference of Korean DTV broadcasting, we measure the channel characteristics in urban, suburban, and rural areas on Jeju Island, Republic of Korea, using a channel sounder and $4{\times}4$ antenna. The path loss (PL) measurement results differ from those of existing propagation models by more than 10 dB. To analyze the frequency characteristics for Korean propagation environments, we derive various propagation characteristic parameters: PL, delay spread, angular spread, and K-factor. Finally, we verify the validity of the measurement results by comparing them with the actual measurement results and 3D ray-tracing simulation results.