• Tunnel and Underground Space
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• v.6 no.1
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• pp.69-74
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• 1996

High temperature confined compressive tests for thermomechanical failure criteria were carried out for Iksan and Whandeung granites. Authors suggested new polynomial type failure coefficient functions by which conventional Hoek-Brown failure criteria was extended to thermomechanical one. Obtained results are as follow; 1) Failure coefficients, m and s of Hoek and Brown's empirical failure criteria were decreased as temperature increased. 2) Theoretically calculated values by suggested equations and experimented ones by confined compressive test were well coincided.

• Honam Mathematical Journal
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• v.43 no.4
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• pp.667-678
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• 2021

Blow-up phenomena for a nonlocal reaction-diffusion system with time-dependent coefficients are investigated under null Dirichlet boundary conditions. Using Kaplan's method with the comparison principle, we establish new blow-up criteria and obtain the upper bounds for the blow-up time of the solution under suitable measure sense in the whole-dimensional space.

• Journal of the Korean neurological association
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• v.36 no.4
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• pp.273-279
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• 2018

Multiple sclerosis (MS) is a diagnosis of exclusion and the lesions or objective findings should disseminate in space and time to diagnose MS. The diagnostic criteria of MS have continuously evolved overtime. The McDonald criteria were originally proposed in 2001, and the revised 2010 McDonald criteria have been used widely. Scientific advances in the past 7 years since 2010 induced the revised 2017 McDonald criteria. All revisions relied entirely on the available evidences, and not expert opinion. In this review, we will provide an overview of the way to diagnose MS and the 2017 McDonald criteria.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.22-30
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• 2010

Light has primary function to enlighten the darkness. However, as development and progresses in media has caused big change in our life, the range of usage and application of light is broadened. And these days, light is actively used as a communication tool in a space. This thesis is based on an idea that a new prospect of light is required and at the same time the theoretical foundation should be established to take active advantage of light. In Chapter two, analysis criteria are established to verify study hypothesis. The applied methodology is to analysis the contents based on literature review. Key words related light in space design are extracted and the frequency of those key words are quantitatively measured. Taking advantage of the result, the characteristics of light are divided into three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. In chapter three, analysis of cases is performed. The cases are selected based on space analyzing criteria established in Chapter two. Qualitative analysis is performed on the cases categorized into natural light and artificial light. Basic analysis elements are evaluated for each case. And each case is allocated to one of three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. Through this analysis, it is found that light in space has prevailing characteristics of 'light as symbolic information' and 'light as communication medium'.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.45.2-45.2
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• 2016

In this study we investigate 195 spacecraft anomalies from 1998 to 2010 from Satellite News Digest (SND). We classify these data according to types of anomaly : Control, Power, Telemetry etc. We examine the association between these anomaly data and daily peak particle (electron and proton) flux data from GOES as well as their occurrence rates. To determine the association, we use two criteria that electron criterion is >10,000 pfu and proton criterion is >100 pfu. Main results from this study are as flows. First, the number of days satisfying the criteria for electron flux has a peak near a week before the anomaly day and decreases from the peak day to the anomaly day, while that for proton flux has a peak near the anomaly day. Second, we found a similar pattern for the mean daily peak particle (electron and proton) flux as a function of day before the anomaly day. Third, an examination of multiple spacecraft anomaly events, which are likely to occur by severe space weather effects, shows that anomalies mostly occur either when electron fluxes are in the declining stage, or when daily proton peak fluxes are strongly enhanced. This result is very consistent with the above statistical studies. Our results will be discussed in view of the origins of spacecraft anomaly.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.133-142
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• 2023

The office environment is changing according to work types, Information Technology (IT) advancements, and the Coronavirus disease (COVID)-19 situation. In order for office space users to perform their tasks comfortably and efficiently, it is necessary to secure individual privacy as well as easy communication among members. In Korea, the demand for improving the acoustic performance of office spaces is also increasing, but the related performance criteria and guidelines have not been established. In this study, standardization of office space acoustic performance measurement and evaluation methods and European countries' acoustic performance criteria were compared and reviewed. It is proposed to comprehensively review international standardization trends and acoustic performance standards in each country and to establish and utilize criteria for evaluating the acoustic performance and satisfaction of office spaces in Korea through our survey. Considering the international standardization direction and compatibility with communication and Public Address (PA) systems, it is appropriate to establish criteria using the speech transmission index or Speech Transmission Index (STI) application index. This criterion will be highly utilizable and compatible. In addition, since the office furniture industry is interested in improving the acoustic performance of office space, it is necessary to establish a labelling system for speech level reduction of office furniture.

• Bulletin of the Korean Mathematical Society
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• v.50 no.1
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• pp.185-200
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• 2013

We study the bounded and the compact weighted composition operators from the Hardy space $H^{\infty}$ into BMOA and into VMOA, from BMOA into $H^{\infty}$, as well as from BMOA into the Bloch space. We also provide new boundedness and compactness criteria for the weighted composition operators on BMOA and on VMOA.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.95-95
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• 2004

The objectives of this study are to perform extensive analysis on internal mass motion for a wider parameter space and to provide suitable design criteria for a broader applicability for the class of spinning spacecraft. In order to examine the stability criterion determined by an analytical method, some numerical simulations will be performed and compared at various parameter points. (omitted)

• Honam Mathematical Journal
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• v.43 no.3
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• pp.417-431
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• 2021

In this study, we introduced the notions of rough statistical convergence and defined the set of rough statistical limit points of a sequence and obtained statistical convergence criteria associated with this set in 2-normed space. Then, we proved that this set is closed and convex in 2-normed space. Also, we examined the relations between the set of statistical cluster points and the set of rough statistical limit points of a sequence in 2-normed space.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.5
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• pp.415-422
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• 2014

There has been a lot of discussion to revise military helicopter crashworthiness design criteria. In this paper, newly revised crashworthiness criteria is analyzed centering around the Crashworthiness Index which is the core content of revised criteria. The Crashworthiness Index(CI) was conceived as an adequate method to quantify the crashworthiness capabilities of a rotorcraft design. The index can rate how well a new or derivative design complies with design requirements. The CI rating is made up of seven assessment areas. While the Basic Airframe Crashworthiness(BAC) area tends to be an objective calculation, other areas of the CI tend to be more subjective. Therefore, in this paper, detail CI calculation process for the BAC area is analyzed to inspect the effectiveness of revised criteria.