• Geomechanics and Engineering
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• v.13 no.2
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• pp.195-215
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• 2017

This paper proposes gob-side entry retaining by roof break and filling in thick-layer soft rock conditions based on the thick-layer soft rock roof strata migration law and the demand for non-pillar gob-side entry retaining projects. The functional expressions of main roof subsidence are derived for three break roof direction conditions: lateral deflection toward the roadway, lateral deflection toward the gob and vertically to the roof. These are derived according to the load-bearing boundary conditions of the main roadway roof stratum. It is concluded that the break roof angle is an important factor influencing the stability of gob-side entry retaining surrounding rock. This paper studies the stress distribution characteristics and plastic damage scope of gob-side entry retaining integrated coal seams, as well as the roof strata migration law and the supporting stability of caving structure filled on the break roof layer at the break roof angles of $-5^{\circ}$, $0^{\circ}$, $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$ are studied. The simulation results of numerical analysis indicate that, the stress concentration and plastic damage scope to the sides of gob-side entry retaining integrated coal at the break roof angle of $5^{\circ}$ are reduced and shearing stress concentration of the caving filling body has been eliminated. The disturbance of coal mining to the roadway roof and loss of carrying capacity are mitigated. Field tests have been carried out on air-return roadway 5203 with the break roof angle of $5^{\circ}$. The monitoring indicates that the break roof filling section and compaction section are located at 0-45 m and 45-75 m behind the working face, respectively. The section from 75-100 m tends to be stable.

• Wind and Structures
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• v.27 no.1
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• pp.11-27
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• 2018

The straight-cone steel cooling tower is a novel type of structure, which has a distinct aerodynamic distribution on the internal surface of the tower cylinder compared with conventional hyperbolic concrete cooling towers. Especially in the extreme weather conditions of strong wind and heavy rain, heavy rain also has a direct impact on aerodynamic force on the internal surface and changes the turbulence effect of pulsating wind, but existing studies mainly focus on the impact effect brought by wind-driven rain to structure surface. In addition, for the indirect air cooled cooling tower, different additional ventilation rate of shutters produces a considerable interference to air movement inside the tower and also to the action mechanism of loads. To solve the problem, a straight-cone steel cooling towerstanding 189 m high and currently being constructed is taken as the research object in this study. The algorithm for two-way coupling between wind and rain is adopted. Simulation of wind field and raindrops is performed with continuous phase and discrete phase models, respectively, under the general principles of computational fluid dynamics (CFD). Firstly, the rule of influence of 9 combinations of wind sped and rainfall intensity on flow field mechanism, the volume of wind-driven rain, additional action force of raindrops and equivalent internal pressure coefficient of the tower cylinder is analyzed. On this basis, the internal pressures of the cooling tower under the most unfavorable working condition are compared between four ventilation rates of shutters (0%, 15%, 30% and 100%). The results show that the 3D effect of equivalent internal pressure coefficient is the most significant when considering two-way coupling between wind and rain. Additional load imposed by raindrops on the internal surface of the tower accounts for an extremely small proportion of total wind load, the maximum being only 0.245%. This occurs under the combination of 20 m/s wind velocity and 200 mm/h rainfall intensity. Ventilation rate of shutters not only changes the air movement inside the tower, but also affects the accumulated amount and distribution of raindrops on the internal surface.

• Korean journal of communication and information
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• v.60
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• pp.5-27
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• 2012

The purpose of this study is to explore the journalist Song Kun-Ho's ideas of Korean Journalism. The journalist Song Kun-Ho was born in 1926 and passed away in 2001. He became a reporter in 1953 when he was a student at department of law of Seoul National University. He has worked for several media and resigned the executive editor at the Dong Ah Ilbo in 1975. At that time, while many reporters of the Dong Ah Ilbo struggled for the freedom of the press, he tried to protect reporters and independence of media. After his resignation of the executive editor, he wrote many columns and several books for Korean nationalism and the democracy of journalism. Instead of working for the authoritarian military regime, he chose a lonely and rough life as an intellectual journalist in action. Finally, he, as a president, established the Hankyoreh daily newspaper which was funded by tens of thousands citizens. He passed away in 2001. His ideas of Korean journalism are nationalism, democracy, and independency. These ideas are very important to restore democratic journalism which has been at risk during the Lee Myung-bak administration.

• Membrane and Water Treatment
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• v.11 no.1
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• pp.79-85
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• 2020

A single-stage deammonification with a sequencing batch reactor (SBR) that simultaneous nitritation, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) occur in one reactor has been widely applied for sidestream of wastewater treatment plant. For the stable and well-balanced SNAD, a feeding strategy of influent wastewater is one of the most important operating factors in the single-stage deammonification SBR. In this study, single-stage deammonification SBR (working volume 30L) was operated to treat a high-strength ammonium wastewater (1200 mg NH₄⁺-N/L) with different feeding strategies (single feeding and nine-step feeding) under the condition without COD. Each cycle of the step feeding involved 6 sub-cycles consisted of aerobic and anoxic periods for partial nitritation (PN) and anammox, respectively. Contrary to unstable performance in the single feeding, the step feeding showed better deammonification performance (0.565 kg-N/m³/day). Under the condition with COD, however, the nitrogen removal rate (NRR) decreased to 0.403 kg-N/m³/day when the Nine-step feeding strategies had an additional denitrification period before sub-cycles for PN and anammox. The NRR was recovered to 0.518 kg-N/m³/day by introducing an enhanced multiple-step feeding strategy. The strategy had 50 cycles consisted of feed, denitrification, PN, and anammox, instead of repeated sub-cycles for PN and anammox. The multiple-step feeding strategy without sub-cycle showed the most stable and excellent deammonification performance: high nitrogen removal efficiency (98.6%), COD removal rate (0.131 kg-COD/m³/day), and COD removal efficiency (78.8%). This seemed to be caused by that the elimination of the sub-cycles might reduce COD oxidation during aerobic condition but increase the COD utilization for denitrification period. In addition, among various sensor values, the ORP pattern appeared to be applicable to monitor and control each reaction step for deammonification in the multiple-step feeding strategy without sub-cycle. Further study to optimize the number of multiple-step feeding is still needed but these results show that the multiple-step feeding strategy can contribute to a well-balanced SNAD for deammonification when treating high-strength ammonium wastewater with COD in the single-stage deammonification SBR.

• Korean journal of communication and information
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• v.29
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• pp.43-71
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• 2005

The study attempts to introduce 'Gotcha Journalism' to the Korea journalism, research and analyze it. Gotcha journalism is the journalistic reporting attitude that the journalists repeatedly and intensively reports public figures, especially politicians' mistakes or happening. 'Gotcha' is abbreviation of "I got you", frequently used in the English and American culture. In order to get the goal of this study, several journalists who are currently working for Chosun, Joongang, Dong-a, Hangyore, Kyunghyang and Seoul, national covering daily newspapers. In addition, the reporters who work for KBS, MBC, and SBS were Interviewed. All journalists who have been worked more than 5 years at the politic department were selected as interviewees. Thus, Intensive interviews are prime source of this study. Based the result of the research, gotcha journalism is externally derived from obsessive interest of Korean people to politics. Internally, it is easy to report happening or mistakes rather than big argument or ideological agenda of the politicians as news for journalists and to catch readers. In addition, the competition with advertising income accelerates this situation. And gotcha journalistic reporting behavior or attitude highly relates to political propensity of the newspapers or broadcastings. Especially some of the newspapers take gotcha journalism as a political struggling tool. It is appeared that another major cause for gotcha journalistic reporting behavior is customer-driven news production.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.2
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• pp.10-19
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• 2020

The park program can adeptly cope with the diversification of leisure needs in accordance with the changing times. The program also makes the relationship between the users and the park itself closer. For this reason, the Seoul Metropolitan Government has operated a variety of programs, beginning with the Botanical Class Program at the Namsan Outdoor Botanical Garden in 1997. The government additionally began to organize park programs by establishing the Park and Leisure Department and three Park Greenery Offices. However, research on park programs is mainly focused on park users. Therefore, this study intends to reveal the structure of the programs by studying the program operation. The specific purposes of this study are '1. Review the institutional characteristics that underlie the operation of the Park Program in Seoul by examining the relevant laws, the operation organizations, and the personnel composition, 2. Analyze the operation methods, such as procurement and the execution of the program, operation costs, and public-private cooperation methods, etc. 3. Analyze the composition and contents of the program from 2015 to 2017, and process and identify the relationship between the structure of the program operation and the program itself.' Summarizing the results obtained from the study, as far as the structure of the first program operation, the support laws were not systematic, but the operating organization was working to establish a system. The second characteristic of the operation is that most of the budget was funded by local governments, but the level of citizen involvement was low. Third, when we looked at the characteristics of the program, the number of programs increased, but they were focused on a specific theme and few programs actively used the park facilities. Based on the results, three tasks can be proposed. The first is that the 'Act on Parks and Green Spaces' should include the concepts and support for park programs. Second, there is a need to change from the ideas of the quantitative increase of programs to qualitative improvements. Lastly, it is necessary to reorganize the Green Seoul Bureau of the Seoul Metropolitan Government into a citizen-led and leisure-oriented organization to promote the park leisure culture. This study has significance, as it was conducted with a service provider, not a program user, unlike many previous park program-related studies. The results of this study will be able to contribute not only to the Seoul Metropolitan Government, but also to other local governments to suggest the direction of the management and the operation of the park for the consumer, and consequently, it will help prepare the long-term vision of parks as the closest leisure location for most citizens.