• Korean Journal of Optics and Photonics
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• v.22 no.2
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• pp.83-89
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• 2011

In order to improve the calculation speed of an integrating-sphere simulator based on a ray-tracing method, parallel processing with OpenMP directive was implemented into the simulator and the randomness of Monte Carlo method was guaranteed by utilizing a parallel random number generator. It was confirmed that simulation results obtained with more than $10^7$ rays showed good agreement with theoretical results within the error range of 0.5%, and that the calculation speed improved as the number of threads increased. Finally, the spatial response distribution functions of a real integrating sphere were simulated and compared with previous results.

• KIPS Transactions on Computer and Communication Systems
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• v.13 no.1
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• pp.31-37
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• 2024

Conventional secret sharing techniques often derive shares from randomly generated polynomials or planes, resulting in lengthy and complex shares that are challenging to memorize and/or manage without the aid of a separate computer or specialized device. Modifying existing secret sharing methods to use a predetermined value, such as a memorizable password or bio-metric information, offers a solution. However, this approach raises concerns about security, especially when the predetermined value lacks randomness or has low entropy. In such cases, adversaries may deduce a secret S with just (t - 1) shares by guessing the predetermined value or employing brute force attacks. In this paper, we introduce a share hardening method designed to ensure the security of secret sharing while enabling the use of memorizable passwords or biometric information as predetermined shares.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.103-114
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• 2014

Significant research has been devoted to the consistency index of the Analytic Hierarchy Process(AHP) from several perspectives. Critics of the consistency index in AHP state that the critical value of consistency index depends on an average of the random index based simulation study using a 9 scale comparison matrix. We found that the distribution of the consistency index followed the skew distribution according to the dimension of the comparison matrix based on a simulation study with a 9 scale comparison matrix. From the simulation study, we suggest a consistency index quantile table to assist the decision-making process in AHP; in addition, we can approximate the distribution of the consistency index to the gamma distribution under the limited assumptions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.2
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• pp.51-57
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• 1985

In the design of civil engineering structures, the designers are invariably faced to the uncertainties and the randomness of the design parameters such as material properties and loads. Even when the structures are built, the actual geometries of the structures are also subject to their random variations from their nominal design values. Thus, the reliability of a structure in terms of these uncertainties and variations becomes a matter of great concern to the structural designers. This study employs the First Order Second Moment Method to evluate numerically the reliability of a simple tension member and discusses the influence on the final failure probability of that structure due to: 1) use of equivalent normal distribution in place of non-normal distribution, 2) linearization of non linear limit state equation. A discussion is also made on the necessity of fundamental studies on the distrubution characteristics of the strength of locally produced construction materials and those of the loads frequently encountered in the structural design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.108-115
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• 2021

The purpose of this study was to investigate the therapeutic effect of fludrocortisone in patients suffering from cervical spinal cord injury (SCI) with orthostatic hypotension (OH). Twenty-six patients with cervical SCI diagnosed with OH through a head-up tilt test were randomly assigned, and they were given either conservative treatment or additional fludrocortisone treatment. Fludrocortisone was administered for 2 weeks, increasing from 0.1 mg to 0.2 mg week . Blood pressure (BP), heart rate (HR), and blood parameters were measured at the beginning and after 2 weeks. After 2 weeks of treatment, there was a significant increase in the baseline BP of the treatment groups (p<.05). When analyzing the drop ratio, there was a tendency for a lower orthostatic BP drop in the treatment groups. Mild adverse events were reported in 7.69% of the treatment groups. Fludrocortisone exhibited therapeutic effects such as preventing cardiovascular complications and continuing rehabilitation through increased baseline BP and reduced OH, and can therefore be considered as a treatment option for OH in patients with SCI.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.4
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• pp.53-66
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• 1990

Rainfall is a phenomenon that shows a high variability both in space and time, Hy drologists are usually interested in the description of spatial distribution of rainfall over watershed. The theory of Kriging, generalized covariance technique using nonstationary mean in the regions under orographic effect, was chosen to construct random surface of total storm depth. For the constructed random surface, the double Fourier analysis of the total storm depths was performed, and the principal harmonics of storm were determined. The local component, or storm residuals was obtained by subtracting the periodic component of the storm from total storm depths. It is assumed that the residuals are a sample function of a homogeneous random field. This random field can be characterized by an isotropic one dimensional autocorrelation function or its corresponding spectral density function. Under this assumption, this study proposed a theorectical model for spectral density function adapted to two watersheds.

• Journal of Preventive Medicine and Public Health
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• v.33 no.1
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• pp.51-55
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• 2000

Objectives . In large-scale field trials, randomization by cluster is frequently used because of the administrative convenience, a desire to reduce the effect of treatment contamination, and the need to avoid ethical issues that might of otherwise arise. Cluster randomization trials are experiments in which intact social unit, e.g., families, schools, cities, rather than independent individuals are randomly allocated to intervention groups. The positive correlation among responses of subjects from the same cluster is in matter in cluster randomization. This thesis is to compare the results of three randomization methods by standard error of estimator of treatment effect. Methods : We simulated cholesterol data varing the size of the cluster and the level of the correlation in clusters and analyzed the effect of cholesterol-lowering agent. Results : In intra-cluster randomization the standard error of the estimator of treatment effect is smallest relative to that in inter-cluster randomization and that in individual randomization. Conclusions : Infra-cluster randomization is the most efficient in its standard error of estimator of treatment effect but other factor should be considered when selecting a specific randomization method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.227-230
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• 2007

본 논문에서는 로봇의 목표물 추적을 위하여 SVM을 이용한 12각형 기반의 Q-learning 알고리즘을 제안한다. 제안한 알고리즘의 유효성을 보이기 위해 본 논문에서는 두 대의 로봇과 장애물 그리고 하나의 목표물로 정하고, 각각의 로봇이 숨겨진 목표물을 찾아내는 실험을 가정하여 무작위, DBAM과 AMAB의 융합 모델, 마지막으로는 본 논문에서 제안한 SVM과 12각형 기반의 Q-learning 알고리즘을 이용하여 실험을 수행하고, 이 3가지 방법을 비교하여 본 논문의 유효성을 검증하였다.

• Review of KIISC
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• v.28 no.1
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• pp.16-21
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• 2018

개인식별번호(personal identification number: PIN)는 숫자로 이루어진 짧은 패스워드로서, 은행 ATM, 디지털 도어락, 스마트 디바이스 등에서 사용자 인증을 위해 널리 쓰이고 있다. PIN을 입력하기 위한 전통적인 키패드 방식의 인터페이스는 엿보기나 녹화 등의 공격에 취약하며, 이를 방지하기 위해 다양한 PIN 입력 방식들이 제안된 바 있다. 그러나, 잘못 설계된 PIN 입력 방식은 무작위 대입 공격 등 다른 공격에 대한 안전성이나 사용자 편의성을 떨어뜨릴 수 있다. 이 논문에서는 특히 스마트 디바이스 상에서 PIN을 안전하게 입력하기 위한 다양한 방식들을 조사하고 이들의 특성을 분석함으로써 안전하고 편리한 PIN 입력 방식의 설계를 위한 방향을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.446-448
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• 2000

본 논문에서는 배전설비도면의 주요 기호인 전주와 전선인식 방법에 관하여 기술한다. 본 논문에서는 원형성에 근거하여 전주후보를 추출한 후 이들 사이의 연결성에 근거하여 전선을 인식한 다음, 전주후보들 중에서 전주를 확인함으로서 전주와 전선을 인식하는 방법을 제안한다. 제안된 방법은 한국전력공사의 배전설비도면들 중에서 무작위로 추출한 표본 약 30매를 대상으로 실험하고 그 결과를 제시한다.