• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.80.2-80.2
• /
• 2019

We present newly discovered dwarf galaxy candidates in deep wide-field images of NGC 1291 obtained with KMTNet. We initially identify 20 dwarf galaxy candidates through visual inspection. 13 out of 20 appears to be high priority candidates, according to their central surface brightness (${\mu}_{0,R}{\sim}22.5$ to $26.5mag\;arcsec^{-2}$) and effective radii (350 pc to 1 kpc). Structural and photometric properties of dwarf candidates appear to be consistent with those of ordinary dwarf galaxies in nearby groups and clusters. Using imaging simulations, we demonstrate that our imaging data is complete up to $26mag\;arcsec^{-2}$ with > 70% of the completeness rate. In order to find an optimal way to automate detecting dwarf galaxies in our dataset, we test detection methods by varying parameters in SExtractor. We find that the detection efficiency from the automated method is relatively low and the contamination due to the artifacts is non-negligible. Therefore, it can be only applicable for pre-selection. We plan to conduct the same analysis for deep images of other nearby galaxies obtained through KMTNet Nearby Galaxy Survey (KNGS).

• The Journal of Engineering Geology
• /
• v.25 no.4
• /
• pp.577-585
• /
• 2015

Contamination of soil due to an oil spill influences its subsequent behavior. An investigation was conducted to study the effect of oil viscosity on compaction characteristics, coefficient of permeability, and shear strength. Water permeability was also determined by using Kerosene, Engine oil, and Crude-oil as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. Direct shear test was conducted to investigate the effect of oil in the pore space in sandy ground. angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.22 no.6
• /
• pp.832-840
• /
• 2019

Recently, pollution from gunpowder due to shell shootings at military drilling sites has raised various environmental concerns. The purpose of this study is to predict the contamination level of RDX in the soil area of the firing range zone near Anwol river watershed, the study site, and the intake area, Anwol river and Imjin river, as a function of time and space. In this study, a multimedia model was developed to predict the variation of RDX contamination by rainfall. The range of the medium was limited to soil, water, and sediment, and excluded the atmosphere, taking into account the physical and chemical properties of RDX with low vapor pressure and low Henry's constant. The pollutant levels of the waters of compartments, including the last section of the Imjin River affecting the water intake, was compared with the environmental standard for RDX.

• Journal of Soil and Groundwater Environment
• /
• v.27 no.3
• /
• pp.1-10
• /
• 2022

Most wells developed in Jeju island before the enactment of the Groundwater Management Ordinance in 2002 are vulnerable to aquifer contamination due to inflow of upper groundwater having the high concentration of nitrate nitrogen, likely due to incomplete grouting in upper section of the wells. Although these wells require entire reinstallation, it is often necessary to rehabilitate the existing wells due to various constraints. Therefore, to identified the inflow section of contaminants, the thermal level sensor (TLS) technique was firstly applied for three wells, which enables to monitor temperature variations in every 50 cm depth. Then, the grouting material was injected to the upper section to prevent the inflow of upper contaminated groundwater into the entire aquifer. By applying TLS technique, it was found that the temperature deviations in the upper groundwater inflow section decreased sharply. Moreover, both the change in the concentration of nitrate nitrogen in the rainy/dry seasons and the average concentrations were found to decrease rapidly after grouting material injection. Consequently, the application of TLS proposed in the study turned out to be appropriate to prevent aquifer contamination.

• Journal of Food Hygiene and Safety
• /
• v.25 no.4
• /
• pp.333-340
• /
• 2010

This study was conducted to evaluate the microbial contamination levels in the processing company of Nuroong-ji. Microbial contamination levels were examined for sanitary indication bacteria such as aerobic plate count, coliforms and fungi, and pathogenic bacteria such as Escherchia coli O157:H7, Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes. Contamination levels were detected differently according to handling materials and purposing work-space. The equipments and raw materials were not seriously contaminated but there were necessary to attend the cross-contamination. A high contamination level was detected at the process where the interference of the employees was relatively higher than the other process. Standardization of the roasting process (l20~$170^{\circ}C$, about 10 min) could be necessary to control the microbial organism effectively on Nuroong-ji manufacturing process. At small/medium size foodstuff manufacturers, it is the most important to improve the recognition level of individual hygiene but also expand a hygiene facility.

• Publications of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.45-47
• /
• 2017

The Infrared Camera onboard the AKARI satellite carried out spectroscopic observations with a grism mode named NG, whose wavelength coverage was $2.5-5.0{\mu}m$. We reinvestigate the current flux calibration for the NG grism mode, with which calculated flux density implausibly decreases at $4.9{\mu}m$ especially for red objects due to the second-order light contamination. We perform a new spectral response calibration using blue and red standard objects simultaneously. New response curves which contain both the first-and second-order light are able to separate each contribution consistently and useful for studies of red objects such as CO ro-vibrational absorption in active galactic nuclei.

• International Journal of Aeronautical and Space Sciences
• /
• v.7 no.1
• /
• pp.84-90
• /
• 2006

The formation flying of satellites has been identified as an enabling technology for many future space missions. The application of conventional thrusters for formation flying usually results in high cost, limited life-time, and a large weight penalty. Various methods including the use of coulomb forces have been considered as an alternative to the conventional thrusters. In the present investigation, we investigate the feasibility of achieving the desired formation using Coulomb forces. This method has several advantages including low cost, light weight and no contamination. A simple controller based on the relative position and velocity errors between the leader and follower satellites is developed. The proposed controller is applied to circular formations considering the effects of disturbances in initial formation conditions as well as system nonlinearity. Results of the numerical simulation state that the proposed controller is successful in establishing circular formations of leader and follower satellites, for a formation size below 100 m.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.1
• /
• pp.39.1-39.1
• /
• 2016

The cosmic distance can be precisely determined using a 'standard ruler' imprinted by primordial baryon acoustic oscillation (hereafter BAO) in the early Universe. The BAO at the targeted epoch is observed by analyzing galaxy clustering in redshift space (hereafter RSD) of which theoretical formulation is not yet fully understood, and thus makes this methodology unsatisfactory. The BAO analysis through full RSD modeling is contaminated by the systematic uncertainty due to a non--linear smearing effect such as non-linear corrections and uncertainty caused by random viral velocity of galaxies. However, BAO can be probed independently of RSD contamination using the BAO peak positions located in the 2D anisotropic correlation function. A new methodology is presented to measure peak positions, to test whether it is also contaminated by the same systematics in RSD, and to provide the radial and transverse cosmic distances determined by the 2D BAO peak positions. We find that in our model independent anisotropic clustering analysis we can obtain about 2% and 5% constraints on $D_A$ and $H^{-1}$ respectively with current BOSS data which is competitive with other analysis.

• The Korean Journal of Air & Space Law and Policy
• /
• v.24 no.1
• /
• pp.153-194
• /
• 2009

The resources of outer space are for the common exploitation of mankind, and it is a common responsibility of mankind to protect the outer space environment. With the rapid development of space science and technology, and especially with the busy space activities of some major space powers, environmental contamination or space debris is steadily increasing in quantity and has brought grave potential threats and actual damage to the outer space environment and human activities in space. Especially We must mitigate and seek out a solution to remove space debris which poses a threat directly to man's exploitation and use of outer space activities in the Low Earth Orbit (LEO) and in the Geostationary Orbit (GEO), through international cooperation and agreement in the fields of space science, economics, politics and law, in order to safeguard the life and property of mankind and protect the earth's environment. While the issue of space debris has been the subject of scientific study and discussion for some time now, it has yet to be fully addressed within the context of an international legal framework. During the earlier stages of the space age, which began in the late 1950s, the focus of international lawmakers and diplomats was the establishment of basic rules which sought to define the legal nature of outer space and set out the parameters for space activities and the nature and scope of activities carried out in outer space were quite limited. Consequently, environmental issues and the risks that might arise from the generation of space debris did not receive priority attention within the context of the development international space law. In recent years, however, the world has seen dramatic advances in technology and increases in the type and number of space-related activities which are being carried out. In addition, the number of actors in this field has exploded from two highly developed States to a vast array of different States, intergovernmental and nongovernmental organizations, including private industry. Therefore, the number of artificial objects in the near-Earth space is continually increasing. As has been previously mentioned, COPUOS was the entity that created the existing five treaties, and five sets of legal Principles, which form the core of space law, and COPUOS is clearly the most appropriate entity to oversee the creation of this regulatory body for the outer space environmental problem. This idea has been proposed by various States and also at the ILA Conference in Buenos Aires. The ILA Conference in Buenos Aires produced an extensive proposal for such a regulatory regime, dealing with space debris issues in legal terms This article seeks to discuss the status of international law as it relates to outer space environmental problem and space debris and indicate a course of action which might be taken by the international community to develop a legal framework which can adequately cope with the complexity of issues that have recently been recognized. In Section Ⅱ,Ⅲ and IV of this article discuss the current status of international space law, and the extent to which some of the issues raised by earth and space environment are accounted for within the existing United Nations multilateral treaties. Section V and VI discuss the scope and nature of space debris issues as they emerged from the recent multi-year study carried out by the ILA, Scientific and Technical Subcommittee, Legal Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space ("COPUOS") as a prelude to the matters that will require the attention of international lawmakers in the future. Finally, analyzes the difficulties inherent in the future regulation and control of space debris and the activities to protect the earth's environment. and indicates a possible course of action which could well provide, at the least, a partial solution to this complex challenge.

• The Korean Journal of Air & Space Law and Policy
• /
• v.27 no.1
• /
• pp.103-122
• /
• 2012

Nowadays, advanced countries and international community in which provide many services and profits due to rapid progress space science and technology whereas there is rising possibility of damage by collision of space object and increase of space debris. I will propose the concept and range of damage in the basis of review of space treaty and space liability convention as form of international order to fair and complete compensate to victim of accident and hazardous space activity. And, I will try to discuss possibility of compensation on personal damage and mental damage, scope of material damage, possibility of compensation about environmental contamination, issue of satellite data sending, place of damage, and so on. Also, I would like to propose establishment of space tribunal and regional cooperative agency.