• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
• /
• pp.102-107
• /
• 1997

A stiffness in a dynamical system is numerically studied to investigate a sensitivity of a reactor to the delayed neutron spectra with the Doppler feedback. To test numerical procedure, we adopted a case of a reactivity accident in a point reactor model. We found that the stiffness is sensitive to a reactivity insertion rate and the delayed neutron spectra in the Doppler feedback phase. Our numerical results show that global reactor characteristics are not very sensitive to the delayed neutron spectra even though their instantaneous ones are sensitive. We present the time evolution of each precursor group explicitly.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2000년도 추계학술대회 논문집
• /
• pp.231-232
• /
• 2000

세계기상기구(World Meteorological Organigation : WMO)에서는 추진하고 있는 지구대기감시(Global Atmosphere Watch : GAW)계획을 효율적으로 수행하기 위하여 기상청에서는 안면도 위치한 기존의 배경대기관측소를 2000년 8월부터 지구대기감시관측소로 개칭하고 업무의 추진을 강화하고 있으며 온실기체는 CFCs, CH$_4$, $N_2$O의 경우 1998년 4월부터, $CO_2$는 8월부터 연속 관측을 실시하고있다. (중략)

• 대한수학회논문집
• /
• 제10권2호
• /
• pp.357-363
• /
• 1995

We study non-existence of $L^2$-harmonic p-forms on a complete, non-compact Riemannian manifold without boundary as extension of results of K. Yano in the case of compact.

• Journal of the Korean Data and Information Science Society
• /
• 제5권1호
• /
• pp.11-20
• /
• 1994

In recent years, nonparametric kernel estimation of regresion function are abundant and widely applicable to many areas of statistics. Most of modern researches concerned with the fixed global bandwidth selection which can be used in the estimation of regression function with all the same value for all x. In this paper, we propose a method for selecting locally varing bandwidth based on bootstrap method in kernel estimation of fixed design regression. Performance of proposed bandwidth selection method for finite sample case is conducted via Monte Carlo simulation study.

• 대한수학회논문집
• /
• 제28권4호
• /
• pp.751-766
• /
• 2013

We study the existence and long-time behavior of solutions to the following semilinear degenerate parabolic equation on $\mathbb{R}^N$: $$\frac{{\partial}u}{{\partial}t}-div({\sigma}(x){\nabla}u+{\lambda}u+f(u)=g(x)$$, under a new condition concerning a variable non-negative diffusivity ${\sigma}({\cdot})$. Some essential difficulty caused by the lack of compactness of Sobolev embeddings is overcome here by exploiting the tail-estimates method.

• 대한수학회지
• /
• 제56권5호
• /
• pp.1309-1331
• /
• 2019

We study the homogeneous Dirichlet boundary value problem of generalized Laplacian systems with a singular weight which may not be in $L^1$. Using the well-known fixed point theorem on cones, we obtain the multiplicity results of positive solutions under two different asymptotic behaviors of the nonlinearities at 0 and ${\infty}$. Furthermore, a global result of positive solutions for one special case with respect to a parameter is also obtained.

• 한국지리정보학회지
• /
• 제17권1호
• /
• pp.107-118
• /
• 2014

본 연구는 전지구 위성 강우자료와 글로벌 지형자료를 이용하여 유출분석을 수행하여 계측자료가 부족한 지역에 대한 강우-유출 관계를 파악할 수 있는 방법을 제시하는 것을 목적으로 하였다. 사용된 위성 강우자료는 CMORPH와 GSMaP_NRT자료를 사용하였고, 글로벌 지형자료는 GTOPO30 및 GLCC자료를 이용하였다. 유출분석을 위한 도구는 IFAS를 이용하였다. 강우 정확도 평가에서 관측강우자료와의 상관계수는 CMORPH 및 GSMaP_NRT에서 0.37 및 0.30로 분석되었다. IFAS를 이용한 유출분석에서 매개변수를 보정하지 않은 경우에도 위성 강우자료를 이용한 모의 첨두유출량이 관측유출량과의 상대오차가 낮았다. 따라서 계측자료가 없는 유역에서의 적용성이 있는 것으로 사료된다. 향후 대표적인 비접근 지역인 북한지역에 대하여 위성강우 및 글로벌 지형자료를 이용하여 유출분석에 활용할 계획이다.

• 품질경영학회지
• /
• 제49권4호
• /
• pp.595-607
• /
• 2021

Purpose: This study introduces a systematic framework to evaluate service satisfaction of cosmetic brands through online review analysis utilizing Text-Mining technique. Methods: The framework assumes that the service satisfaction is evaluated by positive comments from online reviews. That is, the service satisfaction of a cosmetic brand is evaluated higher as more positive opinions are commented in the online reviews. This study focuses on two approaches. First, it collects online review comments from the top 50 global cosmetic brands and evaluates customer service satisfaction for each cosmetic brands by applying Sentimental Analysis and Latent Dirichlet Allocation. Second, it analyzes the determinants that induce or influence service satisfaction and suggests the guidelines for cosmetic brands with low satisfaction to improve their service satisfaction. Results: For the satisfaction evaluation, online review data were extracted from the top 50 global cosmetic brands in the world based on 2018 sales announced by Brand Finance in the UK. As a result of the satisfaction analysis, it was found that overall there were more positive opinions than negative opinions and the averages for polarity, subjectivity, positive ratio, and negative ratio were calculated as 0.50, 0.76, 0.57, and 0.19, respectively. Polarity, subjectivity and positive ratio showed the opposite pattern to negative ratio, and although there was a slight difference in fluctuation range and ranking between them, the patterns are almost same. Conclusion: The usefulness of the proposed framework was verified through case study. Although some studies have suggested a method to analyze online reviews, they didn't deal with the satisfaction evaluation among competitors and cause analysis. This study is different from previous studies in that it evaluates service satisfaction from a relative point of view among cosmetic brands and analyze determinants.

• 예술인문사회 융합 멀티미디어 논문지
• /
• 제8권8호
• /
• pp.883-892
• /
• 2018

최근 물리적 편리성과 정서적 교감을 지원하는 소셜 로봇에 대한 관심이 높아지고, 사물인터넷이 발전함에 따라 소셜 로봇은 단순히 로봇 기능을 넘어 다양한 서비스로서의 진화되고 있다. 따라서 소셜 로봇 서비스의 효과적 개발을 위해서는 사용자와 소셜 로봇 서비스 간의 교감 방법과 기능 적용에 관한 연구가 요구되고 있다. 이에 본 연구는 소셜 로봇 서비스를 유형화하고 서비스 개발 시 고려될 필요가 있는 유형별 요소를 제안하는 것을 목적으로 한다. 이를 위해 본 연구에서는 소셜 로봇의 이론적 정의 및 특성을 기반으로 심도 깊은 사례 조사와 분석을 수행한 후, 교감과 기능을 기반으로 소셜 로봇 서비스의 유형화 작업을 통해 소셜 로봇 서비스를 1) 정서지원형, 2) 동반자형, 3) 안내형, 4) 생활지원형 4가지로 분류하였다. 또한, 효과적인 소셜 로봇 서비스의 개발을 돕기 위해 분류된 유형에 따른 고려 요소를 도출하였다. 본 연구는 소셜 로봇을 활용한 다양한 서비스의 이해 및 개발을 돕는 연구로써 공헌할 것이다.

• Asia Pacific Journal of Business Review
• /
• 제2권1호
• /
• pp.21-52
• /
• 2017

Nowadays every technology is becoming smarter. Consequently, intensive use of ICT in the whole industries and cities enables a sustainable approach to meet enormous productivity, efficiency, transparency and conservation of natural recourses. Likewise, the role of ICT in terms of controlling, monitoring in the energy industry allows integrating potential renewables, bulk energy conservation and reliable optimized operation in the entire system. In this paper outlines challenging issues in renewable energy integration in Mongolia and proposes potential recommendations and conclusions. The author investigated the main technologies used in energy industry mainly smart grid, challenges and policy aspect in Mongolian energy sector by using the primary and secondary approach with case studies and literature based methodologies. Based on the policy aspect and current implementation of smart grid, the paper tries to address the readiness for the main application and future potential ICT driven applications. Furthermore, it concluded that ICT convergence is demanded to overcome the current vulnerabilities and significant momentum to leave behind by using its potential energy recourses and favorable geographical state. Policymakers may find this study useful, as it answers the question of whether ICT investment can ultimately reduce energy consumption and may aid in future planning. Even tough, in order to develop a smart grid and integrating renewables firstly set an appropriate market structure, ICT will key enabler to make energy system more profitable and sustainable. Regarding the result of this study, ICT deployment contribution is a huge demand for future opportunities energy in Mongolia.