• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.27.3-27.3
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• 2017

One of the major discoveries in extragalactic astrophysics made over the past few years is the detection of ultra-diffuse galaxies, a new type of galaxies which appear to be far more numerous than normal galaxies, and which are giants in terms of size, yet dwarfs in terms of luminosity. These galaxies point to the huge discovery potential of the last niche that remains to be explored in observational parameter space: the sky at extremelylow surface brightness. Implications for objects in the Solar System, stellar physics, the interstellar medium, galaxies and cosmology will be addressed, along with the major challenges for pushing the frontiers in ground- and space-based observations.

• Geomechanics and Engineering
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• v.4 no.4
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• pp.281-294
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• 2012

Filtration using granular media such as quarried sand, anthracite and granular activated carbon is a well-known technique used in both water and wastewater treatment. A relatively new pre-filtration method called pebble matrix filtration (PMF) technology has been proved effective in treating high turbidity water during heavy rain periods that occur in many parts of the world. Sand and pebbles are the principal filter media used in PMF laboratory and pilot field trials conducted in the UK, Papua New Guinea and Serbia. However during first full-scale trials at a water treatment plant in Sri Lanka in 2008, problems were encountered in sourcing the required uniform size and shape of pebbles due to cost, scarcity and Government regulations on pebble dredging. As an alternative to pebbles, hand-made clay pebbles (balls) were fired in a kiln and their performance evaluated for the sustainability of the PMF system. These clay balls within a filter bed are subjected to stresses due to self-weight and overburden, therefore, it is important that clay balls should be able to withstand these stresses in water saturated conditions. In this paper, experimentally determined physical properties including compression failure load (Uniaxial Compressive Strength) and tensile strength at failure (theoretical) of hand-made clay balls are described. Hand-made clay balls fired between the kiln temperatures of $875^{\circ}C$ to $960^{\circ}C$ gave failure loads of between 3.0 kN and 7.1 kN. In another test when clay balls were fired to $1250^{\circ}C$ the failure load was 35.0 kN compared to natural Scottish cobbles with an average failure load of 29.5 kN. The uniaxial compressive strength of clay balls obtained by experiment has been presented in terms of the tensile yield stress of clay balls. Based on the effective stress principle in soil mechanics, a method for the estimation of maximum theoretical load on clay balls used as filter media is proposed and compared with experimental failure loads.

• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.105-111
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• 2015

A new species of the genus Robertus Pickard-Cambridge, Robertus subtilis n. sp. is described from Mt. Odae in Gangwon Province, Korea. Theridion serpatusum Guan and Zhu, 1993 and Lathys annulata ${B\ddot{o}senberg}$ and Strand, 1906 are reported for the first time in Korea. Habitus photos and illustrations of these three species are provided.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.153.2-153.2
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• 2008

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.73.2-73.2
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• 2019

Understanding how ionizing radiation propagates from molecular clouds to the intergalactic space is the key to the study of reionization and the emergence of $Ly{\alpha}$ emission from galaxies. In this contribution, I will present our new efforts to better understand the escape of UV photons from turbulent clouds with different masses, star formation efficiencies, and spectral energy distributions using radiation-hydrodynamic simulations. I will also show predicted Lya profiles from turbulent clouds and discuss a few interesting differences identified when compared with the properties of the local green pea galaxies.

• International Journal of Human Ecology
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• v.3 no.1
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• pp.21-36
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• 2002

Recently, early childhood education in England has experienced a significant level of government intervention including reforms for improving it. This study examines to what extent new Labour government initiatives impact preschool education in England and how effectively the English government implements its preschool education policies. This empirical study uses a combination of methods, including documentary analysis, questionnaire, and observation. Findings show that recent English government policy, especially the introduction of a national preschool curriculum framework combined with an inspection process and funding mechanism, appears to have had a strong influence on preschool practices.

• Communications of the Korean Mathematical Society
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• v.9 no.4
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• pp.853-855
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• 1994

The object of present note is to give a very short proof of Stirling's formula which uses only a formula for the generalized zeta function. There are several proofs for this formula. For example, Dr. E. J. Routh gave an elementary proof using Wallis' theorem in lectures at Cambridge ([5, pp.66-68]). We can find another proof which used the Maclaurin summation formula ([5, pp.116-120]). In [1], they used the Central Limit Theorem or the inversion theorem for characteristic functions. In [2], pp. Diaconis and D. Freeman provided another proof similarly as in [1]. J. M. Patin [7] used the Lebesgue dominated convergence theorem.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1564-1567
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• 2008

We demonstrate here a self-aligned printing approach that allows downscaling of printed organic thin-film transistors to channel lengths of 100 - 400 nm. A perfected down-scaled polymer transistors (L= 200 nm) showing high transition frequency over 1.5 Mhz were realized with thin polymer dielectrics, controlling contact resistance, and minimizing overlap capacitance via self-aligned gate configuration.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.335-336
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• 2009

In this paper, I propose an automatic approach to annotating images dynamically based on MBRM(Multiple Bernoulli Relevance Models) using GLCM(Grey Level Co-occurrence Matrix). MBRM is more appropriate to annotate images compare with multinomial distribution. The model is used in limited test set, MSRC-v2 (Microsoft Research Cambridge Image Database). The results show that this model is significantly outperforms previously reported results on the task of image annotation and retrieval.

• Smart Structures and Systems
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• v.6 no.3
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• pp.277-290
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• 2010

Internationally the load carrying capacity of bridges is decreasing due to material deterioration while at the same time increasing live loads mean that they are often exposed to stresses for which they were not designed. However there are limited resources available to ensure that these bridges are fit for purpose, meaning that new approaches to bridge maintenance are required that optimize both their service lives as well as maintenance costs. Wireless sensor networks (WSNs) provide a tool that could support such an optimized maintenance program. In many situations WSNs have advantages over conventional wired monitoring systems in terms of installation time and cost. In order to evaluate the potential of these systems two WSNs were installed starting in July 2007 on the Humber Bridge and on a nearby approach bridge. As part of a corrosion prevention strategy, a relative humidity and temperature monitoring system was installed in the north anchorage chambers of the main suspension bridge where the main cables of the bridge are anchored into the foundation. This system allows the Bridgemaster to check whether the maximum relative humidity threshold, above which corrosion of the steel wires might occur, is not crossed. A second WSN which monitors aspects of deterioration on a reinforced concrete bridge located on the approach to the main suspension bridge was also installed. Though both systems have provided useful data to the owners, there are still challenges that must be overcome in terms of monitoring corrosion of steel, measuring live loading and data management before WSNs can become an effective tool for bridge managers.