• Economic and Environmental Geology
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• v.50 no.3
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• pp.251-256
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• 2017

This study presents measures to enhance the efficiency of Successive Alkalinity Producing Systems(SAPS), a natural biological purification method that prevents environmental pollution arising from the release of Acid Mine Drainage(AMD) from abandoned mines into rivers and groundwater. The treatment of AMD using SAPS is based on biological processing technology that mostly involves sulfate reducing bacteria(SRB). It has been proven effective in real-world applications, and has been employed in various projects on the purification of AMD. However, seasonal decrease in temperature leads to a deterioration in the efficiency of the process because sulfate-reducing activity is almost non-existent during cold winters and early spring even if SRB is able to survive. Against this backdrop, this study presents measures to enhance the activity of the SRB of the organic layer by integrating light emitting diode(LED)s in SAPS and to maintain the active temperature using LEDs in cold winters. Given that mine drainage facilities are located in areas where power cannot be easily supplied, solar cell modules are proposed as the main power source for LEDs. By conducting further research based on the present study, it will be possible to enhance the efficiency of AMD treatment under extreme cold weather using solar energy and LEDs, which will serve as an environmentally-friendly solution in line with the era of green growth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4267-4275
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• 2015

Prefabricated houses are fabricated at the factory for approximately 60 to 80% of the entire construction process, and assembled in the field. In the process of transporting and lifting, internal and external finishes of the unit module are concerned about damages. The purpose of this study is to improve the fixing equipment by analyzing load behavior. The improved fixing equipment would minimize the deformation of internal and external finishes. In order to develop the improved fixing equipment, transporting load on the fixing equipment is analyzed using Monte Carlo simulations, and structural performance is verified by the non-linear finite element analysis. Statistical analysis shows load distribution of unit module is similar with extreme value distribution. Based on the statistical analysis and Monte Carlo simulation, the maximum transporting load is 28.9kN and 95% confidence interval of transporting load is -1.22kN to 9.5kN. The nonlinear structural analysis shows improved fixing equipment is not destructed to the limit load of 35.3kN and withstands the load-bearing in the 95% confidence interval of transporting load.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.293-309
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• 1993

With expanded and extended coverage of the national medical insurance and fast growing health care expenditures, appropriateness of health service utilization and quality of care are concerns of both health care providers and insurers as well as patients. An accurate patient classification system is a basic tool for effective health care policies and efficient health services management. A classification system applicable to Korean medical information-Korean Diagnosis Related Groups (K-DRGs)-was developed based on the U.S. Refined DRGs, and the performance of the developed system was assessed in this study. In the process of the development, first the Korean coding systems for diagnoses and procedures were converted to the systems used in the definition of the U.S. Refined DRGs using the mapping tables formulated by physician panels. Then physician panels reviewed the group definition, and identified medical practice patterns different in two countries. The definition was modified for the differences in K-DRGs. The process resulted in 1,199 groups in the system. Several groups in Refined DRGs could not be differentiated in K-DRGs due to insufficient medical information, and several groups could not be defined due to procedures which were not practiced in Korea. However, the classification structure of Refined DRGs was retained in K-DRGs. The developed system was evaluated fur its performance in explaining variations in resource use as measured by charges and length of stay(LOS), for both all and non-extreme discharges. The data base used in this evaluation included 373,322 discharges which was a random sample of discharges reviewed and payed by the medical insurance during the five-month period from September 1990. The proportion of variance in resource use which was reduced by classifying patients into K-DRGs-r-square-was comparable to the performance of the U.S. Refined DRGs: .39 for charges and .25 for LOS for all discharges, and .53 for charges and .31 for LOS for non-extreme discharges. Another measure analyzed to assess the performance was the coefficient of variation of charges within individual K-DRGs. A total of 966 K-DRGs (87.7%) showed a coefficient below 100%, and the highest coefficient among K-DRGs with more than 30 discharges was 159%.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.15-23
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• 2019

This paper aims to identify the characteristics implied in the process of change of Stephen Sondheim's musical style and to derive the structural communication tools that connect the creator and audience and the implications. The strategies that appear in Sondheim's musical works are the following. First, Sondheim's early musical works follow the principles of book musical and emphasize the integration faithful to the basic elements such as the rhythm and meaning of the lyrics. Second, in the era of early postmodernism, Sondheim attempts the principle of extreme deconstruction through the concept musical Company and pursues rational thought through fragmented dramatic flow. Third, while maintaining dramatic linearity to overcome the lack of immersion caused by extreme deconstruction, Sondheim realizes a more elaborate and formalized fusion style of the principles of integration and deconstruction through the choruses and the songs of the characters in Little Night Music and Sweeney Todd. Finally, Sondheim attempts multiple experiments to break down the boundaries of act and scene and to express new subject matters through his works such as Sunday Park with George and Into the Woods. In conclusion, Sondheim's fusion experiments and strategies are the process of finding a framework and a medium of communication to induce dramatic immersion of audience and at the same time create rational thinking about social problems to deliver the message of the creative work with the leading aesthetics of the modern musical's box-office success.

• Journal of Oriental Neuropsychiatry
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• v.5 no.1
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• pp.9-15
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• 1994

Hwabyung is a culture-related disease generally know among people in Korea, and various studies have been done by the Psychiatrists and by the Oriental Medical Doctors. While the Psychiatrists explain the Hwabyung as a disease having a unique patholoical process, the Oriental Medical Doctors explain it as a symptoms having the character of fire. When interpreted in Oriental Medical point of view, this can be concluded as 1)the cause of the disease is the depression of liver-energy(肝氣鬱結) induced by emotional suppression, 2)the reason why the disease occurs mostly to female is that they usually fail overcoming stresses and have physical and visceral weaknesses, 3)the symptoms are associated with the dynamics of fire, because the disease originates from the rising character of fire and from the inadequit supression of extreme heart-fire(心火) by the kidney-wter(腎水), 4)the reason why the disease goes through chronic process is because of the complexed emotions, converted fire caused by prolonged emotional disorder and inapropreate supression of fire with grow older. This results suggest thst the cooperative study of the clinical examination of the Psychiatrsis and the study on the fire by the Oriental Medical Doctors is necessary to establish the process of the disease, the pathological procedure, the prognosis and the method of treatment.

• Journal of the Korean Vacuum Society
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• v.20 no.5
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• pp.322-326
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• 2011

Etch process of silicon dioxide layer by using capacitively coupled plasma (CCP) is currently being used to manufacture semiconductor devices with nano-scale feature size below 50 nm. In typical CCP plasma etcher system, plasmas are generated by applying the RF power on upper electrode and ion bombardment energy is controlled by applying RF power to the bottom electrode with the Si wafer. In this case, however, etch results often drift due to heating of the electrode during etching process. Therefore, controlling the temperature of the upper electrode is required to obtain improvement of etch repeatability. In this work, we report repeatability improvement during the silicon dioxide etching under extreme process conditions with very high RF power and close gap between upper and bottom electrodes. Under this severe etch condition, it is difficult to obtain reproducible oxide etch results due to drifts in etch rate, critical dimension, profile, and selectivity caused by unexpected problems in the upper electrode. It was found that reproducible etch results of silicon dioxide layer could be obtained by controlling temperature of the upper electrode. Methods of controlling the upper electrode and the correlation with etch repeatability will be discussed in detail.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.88-95
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• 2005

Direct Georeferencing by combined multi-sensor based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The method of combined multi-sensor can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. Consequently, It is possible extreme to reduce the time and expense for the mapping process. In this study, a CCD camera is simultaneously used in combined multi-sensor surveying, and acquired CCD image through Direct Georeferencing produce digital orthoimage. In this process, methods of combining sensor and digital orthoimage are examined and estimated. For the comparison of the positioning accuracy digital orthoimage through Direct Georeferencing, GCPs determined by GPS surveying are used. Two digital orthoimage are produced; one with a few GCP and the other without them. The accuracy of orthoimages produced through combined multi-sensor with GCPs meets that of 1:1,000 maps. Without GCPs, it meets that of 1:5,000 maps.

• International Journal of Fluid Machinery and Systems
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• v.8 no.2
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• pp.102-112
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• 2015

In the Nordic grid, a trend observed the recent years is the increase in grid frequency variations, which means the frequency is outside the normal range (49.9-50.1 Hz) more often. Variations in the grid frequency leads to changes in the speed of rotation of all the turbines connected to the grid, since the speed of rotation is closely related to the grid frequency for synchronous generators. When the speed of rotation changes, this implies that the net torque acting on the rotating masses are changed, and the material of the turbine runners must withstand these changes in torque. Frequency variations thus leads to torque oscillations in the turbine, which become dynamical loads that the runner must be able to withstand. Several new Francis runners have recently experienced cracks in the runner blades due to fatigue, obviously due to the runner design not taking into account the actual loads on the runner. In this paper, the torque oscillations and dynamic loads due to the variations in grid frequency are simulated in a 1D MATLAB program, and measured grid frequency is used as input to the simulation program. The maximum increase and decrease in the grid frequency over a 440 seconds interval have been investigated, in addition to an extreme event where the frequency decreased far below the normal range within a few seconds. The dynamic loading originating from grid frequency variations is qualitatively found by a constructed variable $T_{stress}$, and for the simulations presented here the variations in $T_{stress}$ are found to be around 3 % of the mean value, which is a relatively small dynamic load. The important thing to remember is that these dynamic loads come in addition to all other dynamic loads, like rotor-stator interaction and draft tube surges, and should be included in the design process, if not found to be negligible.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.957-968
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• 2017

Purpose: There are lots of efforts to increase the revenue of on-line travel agency due to the extreme competition in the hospitality industry. One of the way to improve the revenue is applying new concepted service for their business. In this study, it is introduced an innovative system design of hotel reservation for the on-line travel agency using the concept of an opaque product. Methods: By adopting the opaque product at the hotel reservation system, the reservation requests can increase because the customer tends to feel that they purchase the hotel service with relatively cheap price. The overall process for an innovative hotel reservation system is presented and the core algorithm to implement this system is also suggested through a mathematical model based optimization method. Results: To validate and to examine the proposed process and core algorithm, a numerical example is provided with the modified data of the hotels in Seoul metropolitan city. The discount prices and the overall revenue of hotels are generated according to hotel grade. Conclusion: It is confirmed that the revenue of the hotel tends to increase according to its grade. This is because that the customer want to use the new service which applying the concept of opaque product when the higher discount ratio are decided for lower grade hotels.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.285-285
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• 2011

EUVL (Extreme Ultra Violet Lithography) is one of competitive lithographic technologies for sub-30nm fabrication of nano-scale Si devices that can possibly replace the conventional photolithography used to make today's microcircuits. Among the core EUVL technologies, mask fabrication is of considerable importance since the use of new reflective optics having a completely different configuration compared to those of conventional photolithography. Therefore new materials and new mask fabrication process are required for high performance EUVL mask fabrication. This study investigated the etching properties of SnO2 (Tin Oxide) as a new absorber material for EUVL binary mask. The EUVL mask structure used for etching is SnO2 (absorber layer) / Ru (capping / etch stop layer) / Mo-Si multilayer (reflective layer) / Si (substrate). Since the Ru etch stop layer should not be etched, infinitely high selectivity of SnO2 layer to Ru ESL is required. To obtain infinitely high etch selectivity and very low LER (line edge roughness) values, etch parameters of gas flow ratio, top electrode power, dc self - bias voltage (Vdc), and etch time were varied in inductively coupled Cl2/Ar plasmas. For certain process window, infinitely high etch selectivity of SnO2 to Ru ESL could be obtained by optimizing the process parameters. Etch characteristics were measured by on scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Detailed mechanisms for ultra-high etch selectivity will be discussed.