• Management & Information Systems Review
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• v.5
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• pp.33-59
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• 2000

Problem definition is as important as problem solving in decision making. Decision makers, however, tend to see problem partly or to define it unclearly. The researchers on decision making tend to lay a focus only on the Process of solving the given problem. This dissertation empirically studied the Problem diagnosis and definition in the decision making process. This study developed three kinds of DSS(Decision Support System) for the research and analyzed the effectiveness of the problem diagnosis and definition using DSS developed in this study. The three kinds of DSS are K-T(Kennel and Tregoe) DSS which is a method of table-styled information Presentation, and F-N(Fact-Net) DSS and C-E(Cause and Effect) DSS which are methods of graphic-styled information presentation. The empirical study was conducted twice; the pilot test and the main test. The samples of experiment are 218 students for the pilot test and 259 students for the main test. The author used K-T DSS and F-N DSS for the pilot test, and the revised K-T DSS and C-E DSS for the main test. A questionnaire survey method was included in the main test process The result of the study shows that the group using DSS in problem diagnosis and definition is more effective than the group not using DSS. A table-styled information presentation DSS, K-T, turns out more effective than a graphic-styled information presentation DSS, F-N, K-T DSS and C-E DSS showed no significant differences in the effectiveness in the main test. These results indicate that the use of DSS in the stage of problem diagnosis and definition is very effective and the methods and types of system design are a significant factors for DSS development.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.245-252
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• 2004

Two biofilter tests were conducted under different operating conditions. Test # 1 was performed to treat VOCs generated from a paint booth. The second test was performed to treat VOCs generated from chemical manufacturing processes. The volume of biofilter media was 4.3 $m^3$. For the test # 1, the biofilter was operated for 30 days with 99.9% reduction ratio. Range of temperature of each stage of the biofilter media was measured between $34^{\circ}C$ and $73^{\circ}C$. All the temperatures of stages reduced gradually after the initial dramatic increase. For the test # 2, the biofilter experiment was conducted for 14 days. In this case, the biofilter was installed outdoor and the experiment was performed during wintertime. Therefore, temperature management for the biofilter was needed. Seven-centimeter thick fiberglass insulation and $150^{\circ}C$ steam heating were used to overcome the outside freezing cold weather during test # 2. Temperature of stage # 5 was measured the highest and that of stage # 1 was the lowest. More acclimation time and test period was needed to determine the maximum loading rate.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.3
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• pp.43-60
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• 2005

In september 2004, a new pilot certificate scheme referred to as Sport Pilot Certificate was declared official and standardized in the US. The designation of Light-sport aircraft and the details of the relevant pilot certificate policy was announced out of the perception that a new regulation is required to be applied whereby the limitations on the manufacturing process enhancements and current aviation rules are considered the triggering factors. US Federal Aviation Regulation retains a comprehensive range of airworthiness certificates and aircrafts are managed systematically in accordance with FAR 21, 103. The airworthiness are further segregated into sub categories, which allows differentiated management. Korean Aviation Law classify aircraft into five different categories and powered air vehicle that weighs more than 150kg(19liters fuel capacity) for one seat, 225kg for two seats(38liters fuel capacity) while the systems that fall under a specific mass threshold level are known as ultralight vehicle. The research discusses the policy of the sport pilot certificate and the light-sport aircraft ratings announced official by the Federal Aviation Administration in an intuitive fashion with the analysis of the operations providing the evidence as to the viability of adopting the policy in local grounds. Based on the findings, the report discusses the case for introducing the light-sport aircraft and make recommendation on a strategy of applying the policy in Korea with respect to the pilot certificates, safety agenda, and the written test for the pilot certificate, and operating efficiency.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.602-612
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• 2001

The equation of the particle collection efficiency proposed by Deutsch has been modified through the various experiments to correct the errors caused by the assumptions made for the equation. In order to get an modified Deutsch equation that can be applied to real conditions, a pilot scale electrostatic precipitator is used. The effects of operational variables on the particle collection efficiency are evaluated. Particle resistivity, gas temperature, moisture contents in gas, gas velocity and particle concentration are used as the operational variables. Two different types of coal fly-ash obtained from the fluidized bed combustor and the pulverized coal combustor are used as test particulate to evaluate the effect of the physiochemical and electrical characteristics of the particle on the particle collection efficiency. The experimental results are fitted with the modified Deutsch equation made by Matts-Ohnfeldt and the extended Deutsch equation made by E. C. Potter to evaluate the effect of the particle characteristics and the operation conditions on the particle collection efficiency of the electrostatic precipitator.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.121-128
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• 2009

Objectives of this study were to investigate influencing factors of detention time, particle size distribution, and filter medium characteristics for waterworks sludge dewatering. The stepped pressure filtration was carried out with lab scale apparatus and the filter press pilot test for dewatering was conducted at the water treatment plant. Effects of filter medium and polymer dose were examined through observing water content and dewatering velocity and cyclic dewatering rate with filter press pilot test. Relationships among detention time, particle size distribution and filtration resistance were analyzed. Prolongation of sludge detention time was found to cause blinding phenomenon in cake and filter medium and to decrease dewatering process efficiency. The average specific resistance increased according to detention time. In pilot test of dewatering for thickened sludge with Nylon Multi-NY840D and Nylon Mono-100% filter media, dewatering velocities were 0.92 and $0.93kg\;DS/m^2{\cdot}hr$ according to 0.1% polymer dose of dried solids weight base. And cyclic dewatering rates were 2.45 and $2.50kg\;DS/m^2{\cdot}cycle$ cycle for the Nylon Multi-NY840D and Nylon Mono-100% media. Dewatering velocity of polymer dosed sludge was observed to be higher than that of non-polymer sludge.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.1
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• pp.43-50
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• 1999

In spite of low energy requirement, and operation and construction cost, biofilters with soil beds have not been operated efficiently. Because of excess moisture in winter and rainy periods, saturated pores in the bed prevent passage and sorption of odorous compounds. Sometimes this results in septic conditions that release previously sorbed and oxidized sulfur. Therefore, an economical and effective alternative needs to be developed. The objectives of this study were to confirm applicability of the granular scrap tires with compost for treating odorous gas as well as to obtain optimum design parameters for proposed system. In lab-scaled test, multiple stage reactors had lower headloss than a single stage reactor and less headloss was occurred for the gas with higher moisture content. For practical purpose, pilot-scaled reactor was operated to remove odor from septic tank, manure and animal wastewater treatment plant and composting machine. According to the results of pilot scaled test, $H_2S$ can be always removed completely and ammonia/amine can be removed excellently when proper moisture content is provided. The results from lab and pilot test showed that granular scrap tire could be replaced with soil as supporting material for biofilter showed excellent drainage because of its ability to reject moisture.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.3
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• pp.24-33
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• 2021

Although it is the first transportation method to apply the 'Ground Effect' applied to aircraft to ships, WIG ships, which are classified as 'Ships' operating on the water under international law. The pilot aptitude test, which has the effect of preventing safety accidents in advance, has not yet been established as a legal system in S. Korea, after being certified by the Korean Register of Shipping (KR) for the first time in the world in March 2020. Therefore, the purpose of this study is to ensure that identifying the importance, recognition, correlation, etc. of the tools and items of aptitude testing, from a group of experts, can be used appropriately for future development of legal aptitude testing tools. As a method of study, the questionnaire method was used, and the analysis confirmed that the tools used on aircraft and ships could be used appropriately. In particular, Due to the characteristics of the WIG ships, it was confirmed that it is necessary to develop more specifically in the future, the operational qualifications and physical fitness items, which are the aptitude evaluation items.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4274-4282
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• 2011

In this study, Fenton reaction was studied for the possibility of applying as advanced treatment and its optimal condition for the removal of refractory organics from the dye wastewater. Fenton reaction was applied to remove refractory organics after the bio-treatment (secondary treatment) inside test laboratory and on-site pilot plant. Wastewater from the secondary treatment was used and its $COD_{Mn}$ was measured as 30~50mg/L. After the Fenton reaction, the optimal condition was found as pH 3~3.5, reaction time 2~2.5hr, chemical input ratio of ($FeCl_2$(33%)/$H_2O_2$(35%)) was 3 : 1. When chemical input ratio of ($FeCl_2$(33%)/$H_2O_2$(35%)) was at its optimal, amount of sludge volume ($SV_{2hr}$) was 21~28%. With pilot plant test, removal rate was heavily influenced by the hydraulic retention time(HRT), and optimum value of HRT was 2.0 hr. When pilot plant($2m^3/d$) was placed on-site and operated continuously, it showed steady and fairly good treatment of COD where COD removal rate was 60~70%, treated water showed below 20mg/L.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.160-160
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• 2010

ELVs (End-of-Vehicles) in Korea incrasease continusely because of increase of used car. Automobile Shredder Residue (ASR) is final product of ELVs (End-of-Vehicles) after recycling. Automobile Shredder Residue are composed of light and heavy fluffs and soil/dust. In this study, 5 ton/day pilot plant of shaft type has been designed and constructed and 15 times of test run were performed. For the stable operation, operation conditions such as the amount of fed ASR and cokes, air flow and temperature in the gasification melting system have been changed and the composition of the produced gas such as $H_2$, CO and $CH_4$ and air pollution compound including dioxin discharged from the stack have been analyzed.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.462-468
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• 2010

A new course keeping controller for RIB(Rigid Inflatable Boat)-type USV(Unmanned Surface Vehicle) is developed using pilot's steering pattern. A pilot's simple steering pattern is found out from various course change tests. It is used to course keeping algorithm, suitable for large course change more than 60 degrees. To validate the course keeping controller, sea trial tests are conducted. From sea trial test, new course keeping controller shows good performance with less overshoot, maximum roll angle less than $20^{\circ}$, which makes it possible that fast course changes without slip motion of USV.