• Journal of the Korea Society of Computer and Information
• /
• v.26 no.6
• /
• pp.167-172
• /
• 2021

The objective of this study is to present the academic implications and developmental direction of the police assigned for special guard system through big data analysis on the objective and macroscopic viewpoint of the media. As research method, this study conducted the analysis on 'police assigned for special guard' and the analysis of related words that would visualize the keywords highly related to keyword trend and news. Also, after dividing the period into the 1990s, 2000s, and 2010s, the number of relevant articles in each period was drawn for understanding the flow. In the results of this study, the perception of media report of police assigned for special guard was about the recruitment of police assigned for special guard, and relevant events/accidents, which showed the coexistence of positive interest in the recruitment of police assigned for special guard and negative image of events/accidents related to police assigned for special guard. As a result, however, the necessity and demand for police assigned for special guard are increasing. Thus, the police assigned for special guard should be engaged in work after carefully thinking of its role in charge of ethical responsibility and safety as an axis for maintaining the national safety and social order.

• Journal of Soil and Groundwater Environment
• /
• v.29 no.1
• /
• pp.39-50
• /
• 2024

Slags from steel-making industry have been recycled at a target rate of 95% and most of them are recycled as media-contact type such as fill and cover materials in Korea. However, as they contain free phase CaO during their generation, they may not only expand and collapse upon contact with water, but high pH leachate and heavy metals leaching may occur. In this study, the Korean leaching procedure (KLP) and up-flow percolation test were performed for the samples collected from 17 steel-making production plants in Korea. The waste quality criteria were met in all tests, but pH of the samples was above 10. There are no regulations on the pH of leachate in most of the countries, however, Germany, Italy, and Australia have set a pH range of 10 to 13 for the leachates. Although slag leachate cannot be considered hazardous based only on its high pH, it is necessary to reduce the pH of leachate to minimize the impact on the surrounding environment. Furthermore, conflicting regulations on wastes handling and management in Korea created confusion on the types of wastes subject to recycling. Therefore, an appropriate management plan for steel-making slags needs to be established. To this end, this study attempted to provide a guideline for managing steel-making slag waste by considering international guidelines and current management practices in Korea.

• The Journal of Engineering Geology
• /
• v.13 no.1
• /
• pp.51-65
• /
• 2003

A series of numerical simulations were carried out using STOMP( Subsurface Transport over Multiple Phase) simulator. The flow and distribution of LNAPL were analyzed in homogeneous fine and coarse sand. Vertical movement of LNAPL is faster in the coarser sand. But the total volume of LNAPL retained in the unsaturated zone is larger in the finer sand. A fine layer in the coarse sand domain is also simulated. The results showed that the retained LNAPL volume and shape are highly influenced by the Position of the fine layer. Flow and distributions of LNAPL were simulated when there were heterogeneous lenses in the sand domain. Water table fluctuation was also considered. In these cases, it was found that the heterogeneous lens was a barrier to LNAPL flow, and water table fluctuation stimulated the downward movement of retained LNAPL. The LNAPL flow and distribution observed in these numerical experiments show that in the subsurface environment, the behaviors of LNAPL highly depend on heterogeneities of unsaturated zone and the dynamic hydrogeologic condition such as water table fluctuation. These results can explain some of the complexity of LNAPL flow and distribution Patterns in LNAPL contaminated field sites.

• Journal of Digital Convergence
• /
• v.11 no.5
• /
• pp.237-243
• /
• 2013

This study aims to examine the modified $A^2/O$ process is useful to reduce the environmental pollution caused by nutrient in wastewater. Specific results are as follows: The removal rate was evaluated at each time period, ie., 18h, 8h, 6h, and 3h after the reaction started. The anoxic rate was more than 94-97% from 18h to 6h but was less than 50% before 6h. Thus, the test of nitrification was done using 6h as the optimal anoxic retention time and the aerobic retention time set at 24h. When the flow change was 1:1, the average ammonia concentration inputted was $30mg/{\ell}$. Returned top nitric acid solution and the concentration of ammonia solution falling into the anoxic reactor was about 50％ of the initial concentration, and the flow change was 1:2, the concentration of ammonia falling into the anoxic reactor was about 62% of that of influxed ammonia. And the results of this study showed that the nitrogen removal rate can be improved by inputting untreated nitric acid and changing the flow of top nitrate solution using the modified $A^2/O$ method.

• Journal of Korea Water Resources Association
• /
• v.36 no.6
• /
• pp.1013-1023
• /
• 2003

This study was performed to improve water quality of stream by applying hydraulic structures (weir and river bed material) made of porous concrete. The physical and chemical characteristics of porous concrete were measured to estimate application possibility of it in hydraulic structures and it was considered as a proper material for the hydraulic structures. In the results of comparison for the component of matters attached on the hydraulic structures made of porous and ordinary concrete, DW (dry weight) amount attached on porous concrete was 1.6 times higher than that on ordinary concrete under the condition of the same flow rate but influence by flow rate (difference of 10 times) was not shown. Therefore, we could understand that the material of media was more important in DW amount than flow rate. The rate of AFDM (ash free dry mass) to DW also was more at porous concrete than at ordinary concrete. Especially, the high rates of nitrogen and phosphorous in matters attached on porous concrete verify that they were removed by assimilation, adsorption and metabolism of periphyton. The removal percentage of SS, BOD, COD, T-N and T-P by hydraulic structures applying porous concrete compared with ordinary concrete was increased by 34.6%, 36.9%, 33.9%, 18.3% and 21.6%, respectively. Therefore, applying porous concrete to hydraulic structure is expected to contribute to improvement of stream water quality.

• Journal of Korea Game Society
• /
• v.17 no.1
• /
• pp.27-40
• /
• 2017

This study explores the concept of Study Time Management Service(STMS) and the characteristics of gamification elements in STMS, in order to propose the meaning of psychic anti-entropy and the role of a meme as a new gamification element. The goal of gamification in education is to enhance study motivation and lead to flow by integrating similarities between game and study into the study environment. STMS also aims at such a goal. However, it differs in that the external anti-entropy environment, such as blocking apps, is connected with game mechanics or game thinking to give extrinsic motivation. It is also unique in that it uses a meme as a new gamification element to induce intrinsic motivation. In particular, a meme as a kind of guideline for performing study activities induces intrinsic motivation to imitate good study patterns and offers the driving force to sustain psychic anti-entropy state. Therefore, gamification in STMS is to strengthen the external anti-entropy environment by utilizing game mechanics or game thinking, and to maintain the psychic anti-entropy state by utilizing a meme of study patterns.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.10 no.5
• /
• pp.644-650
• /
• 2018

The paper provides some developments of a numerical approach ("Numerical Calculation of Flow Within Armour Units", FWAU) to the design of rubble mound breakwaters. The hydrodynamics of wave induced flow within the interstices of concrete blocks is simulated by making use of advanced, but well tested, CFD techniques to integrate RANS equations. While computationally very heavy, FWAU is gaining ground, due to its obvious advantages over the "porous media", i.e. the possibility of accounting for the highly non stationary effects, the reduced need of ad hoc calibration of filtration parameters and also - in perspective - the evaluation of hydrodynamic forces on single blocks. FWAU however is a complex technique, and in order to turn it into a practical design tool, a number of difficulties have to be overcome. The paper presents recent results about this validation, as well as insight into fluid dynamical aspects.

• Journal of The Korean Astronomical Society
• /
• v.37 no.5
• /
• pp.605-609
• /
• 2004

We present a set of high-resolution 3D MHD simulations exploring the evolution of light, supersonic jets in cluster environments. We model sets of high- and low-Mach jets entering both uniform surroundings and King-type atmospheres and propagating distances more than 100 times the initial jet radius. Through complimentary analyses of synthetic observations and energy flow, we explore the detailed interactions between these jets and their environments. We find that jet cocoon morphology is strongly influenced by the structure of the ambient medium. Jets moving into uniform atmospheres have more pronounced backflow than their non-uniform counterparts, and this difference is clearly reflected by morphological differences in the synthetic observations. Additionally, synthetic observations illustrate differences in the appearances of terminal hotspots and the x-ray and radio correlations between the high- and low-Mach runs. Exploration of energy flow in these systems illustrates the general conversion of kinetic to thermal and magnetic energy in all of our simulations. Specifically, we examine conversion of energy type and the spatial transport of energy to the ambient medium. Determination of the evolution of the energy distribution in these objects will enhance our understanding of the role of AGN feedback in cluster environments.

• Journal of Mechanical Science and Technology
• /
• v.20 no.12
• /
• pp.2284-2291
• /
• 2006

The present study investigates gas residence time and mixing characteristics for various swirl numbers generated by injection of secondary air into a lab-scale cylindrical combustor. Fine dust particles and butane gas were injected into the test chamber to study the gas residence time and mixing characteristics, respectively. The mixing characteristics were evaluated by standard deviation value of trace gas concentration at different measurement points. The measurement points were located 25 mm above the secondary air injection position. The trace gas concentration was detected by a gas analyzer. The gas residence time was estimated by measuring the temporal pressure difference across a filter media where the particles were captured. The swirl number of 20 for secondary air injection angle of 5$^{\circ}$ gave the best condition: long gas residence time and good mixing performance. Numerical calculations were also carried out to study the physical meanings of the experimental results, which showed good agreement with numerical results.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.4
• /
• pp.763-781
• /
• 2011

We present a texture-based hatching technique for color images and video. Whereas existing approaches produce monochrome hatching effects in considering of triangular mesh models by applying strokes of uniform size, our scheme produces color hatching effects from photographs and video using strokes with a range of sizes. We use a Delaunay triangulation to create a mesh of triangles with sizes that reflect the structure of an input image. At each vertex of this triangulation, the flow of the image is analyzed and a hatching texture is then created with the same alignment, based on real pencil strokes. This texture is given a modified version of a color sampled from the image, and then it is used to fill all the triangles adjoining the vertex. The three hatching textures that accumulate in each triangle are averaged and the result of this process across all the triangles forms the output image. We can also add a paper texture effect and enhance feature lines in the image. Our algorithm can also be applied to video. The results are visually pleasing hatching effects similar to those seen in color pencil drawings and oil paintings.