• Journal of ILASS-Korea
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• v.9 no.1
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• pp.8-14
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• 2004

future exhaust emission limits for diesel-driven passenger cars will force the automotive company to significantly develop of the new technologies of diesel engine respectively of the drive assemblies. As we know, the contributions of soot and nitrogen oxide is the main problems in diesel engine. Recently, as a result, the pilot injection of common-rail fuel injection system recognizes an alternative function to solve an environmental problem. This study describes the effect of the nozzle structure and driven characteristic of injector on pilot injection fur a passenger car common-rail system. The pilot spray structure such as spray tip penetration, spray speed and spray angle were obtained by high speed images, which is measured by the Mie scattering method with optical system fur high-speed temporal photography. Also the CFD analysis was carried out for fuel behavior under high pressure in between needle and nozzle of injector for common-rail system to know the condition of initial injection at experiment test. It was found that solenoid-driven injector with 5-hole was faster than 6-hole injector in spray speed at same conditions and piezo-driven injector showed faster response than solenoid injector.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.30-40
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• 2015

Recently, the need of RPA(Remotely Piloted Aircraft) pilots is increasing rapidly with many requirements in order to be a beginner RPA pilot, including basic flight training, instrument flight qualification training, and aircraft type switching training. When RPA pilot gets disqualified, there will be generated much waste of efforts and expenses of trainees those pilots who are disqualified. Therefore, the methodology of pre-verifying those pilots who are not proper as RPA pilots through various scientific methods will save time and expenses with pre-reducing the pilots who will get disqualified later on. The methodology of aptitude test of RPA pilots is laid out as a consideration of pre-study of RPA pilots work analysis, and select types of aptitude test. A suitability of aptitude test is verified. In order to diagnose the flight aptitude precisely, it requires to be developed. Flight aptitude test tools might be connected with training program which could foster piloting aptitude with pre-diagnosing RPA pilot trainee selecting process. For that reason, we made an experiment in order to verify credibility and suitability of these selected programs with developing RPA pilot aptitude test tools. And also, we analyzed relationships among characteristics, analysis of data, and variables to verify the efficiency of data from prior experiment. Through this thesis, we expect to raise efficiency of flight training by providing pre-flight aptitude test information of RPA pilots.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.60-67
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• 2024

The majority of civil aviation accidents are caused by human factors, and especially for rotary-wing aircraft, accidents often occur in situations where pilots unexpectedly or unintentionally enter into instrument meteorological conditions (IIMC). This research analyzed the error rates of rotary-wing aircraft pilots under low visibility conditions from various angles to gain insights into flight characteristics and to explore measures to reduce accidents in IIMC situations. The occurrence rate of errors by pilots under low visibility conditions was examined using a flight simulator equipped with motion, with 65 pilots participating in the experiment. Flight data obtained through the experiment were used to aggregate and analyze the number of errors under various conditions, such as reductions in flight visibility, the presence or absence of spatial disorientation, and the pilot's qualifications. The analysis revealed peculiarities in flight characteristics under various conditions, and significant differences were found in the rate of error occurrence according to the pilot's qualification level, possession of instrument flight rules (IFR) qualifications, and during different phases of flight. The results of this research are expected to contribute significantly to the prevention of aircraft accidents in IIMC situations by improving pilot education and training programs.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.334-339
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• 2013

A pilot-scale sand-box experiment simulating a lateral of collector well used in riverbank filtration was performed, and hydraulic head distributions along the lateral were measured according to the various drawdowns at the well. The results of this experiment were compared to the predicted values obtained using a theory previously developed by Kim in order for its validation. This theory predicts the head loss in a large-scale lateral given the loss in a small-scale one, and to have actual values for comparison, the results from a lab-scale experiment previously performed by Kim were employed. Comparing the experimental values to the extrapolated value indeed confirmed the validity of the theory. A procedure to determine the hydraulic head distribution of a practical-scale lateral was also presented applying the theory to the experimental result of this study in an effort to show the process of lateral design for riverbank filtration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.998-1004
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• 2002

This paper reports a design of feedforward linear power amplifier using pilot tone for IMT-2000 band repeaters accepting multi-carrier. As this time pilot tone is applied to the circuit differently from the existing method. Only one pilot tone is used in both 1-st loop(IMD abstraction loop) and 2-nd loop(IMD cancellation loop) to cancell IMD signals automatically according to variation of frequency or power level of input signals. As an experiment, in range of 2110 MHz - 2170 MHz at LPA output power of $20 W_{avg}$, IMD characteristics of over 20 dB was improved maintaining below -60 dBc considering respective 20 MHz. Therefore the supposed feedforward linear power amplifier can be used for linear power amplifier in IMT-2000 band repeaters.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.09a
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• pp.199-208
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• 1994

This paper presents an evaluation of new drill and blast method with two different drilling directions for pilot tunnel enlargement using numerical experiment and field test. To evaluate the effieiency of new tunnel enlargement method, field tests were performed and compared with conventional drill and blast method. Also, three dimensional transient dynamic analysis was made to investigate the effect of the ground vibration when blasting was performed at same position using the equivalent single hole charge.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.73-76
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• 1998

악취 물질은 주로 피혁공장, 화학공장, 유지공장, 슬러지처리장 등에서 발생하며 작업장 내의 근로자뿐만 아니라 인근 지역주민들에게 정신적인 불쾌감을 주는 동시에 인체에 매우 유해한 물질들이다. 이들 악취물질중 유황화합물질로는 황화수소, 머켑탄류가 있으며 아주 적은 농도에서도 악취를 느낄 수 있고 자극이 매우 심하다. 특히, 황화수소와 메틸머켑탄은 거의 모든 악취의 주요 원인물질로서 작업현장 내에 혼합물질로 존재하며, 쾌적한 작업환경을 위해서는 이들의 처리가 반드시 필요하다. (중략)

• KSBB Journal
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• v.22 no.4
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• pp.191-196
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• 2007

This study used biofilm process, which needs simple operation, maintenance and smaller facility area than conventional activated sludge process with the small plant operation, in the treatment of increasing sewage with the rapid industrial growth. The reactor used in this study consists of one anaerobic and one aerobic chamber filled with waste ceramic and waste vinyl as media and the treated sewage was from restaurant source. The experiment was scaled up from lab. to pilot scale and lasted for about 100 days. We focused on the removal efficiency of organics, nitrogen and phosphorus with constant HRT and continuous aeration. The removal efficiency of $BOD_5$ and SS were 94.33% and 87.77% respectively, which was a satisfaction level. However the removal efficiency of $COD_{Cr}$ was 81.46% somewhat below the desired level of 90%, and that of T-N and T-P showed 71.92% and 21.10% respectively, that was below the expected value. The removal efficiency of $COD_{Cr}$ and T-N in the pilot scale was about 10% low compared with the lab.-scale.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1112-1117
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• 2014

Unmanned aerial vehicles (UAVs) are a popular research topic because of a great ripple effect in the future. However, current UAV technologies cannot be applied to manual aerial vehicles without any modification. As an alternative to current UAV technology, humanoid robots are adopted as pilots. If a humanoid robot controls an aerial vehicle autonomously, not only could manual aerial vehicles be utilized as UAVs, but the humanoid robot would also be put into an environment created for humans and conduct some missions suitable for humans. Humanoid robots are also able to handle tools and equipment designed for humans. In order to prove that a humanoid robot can pilot an airplane, an experiment is performed and the results of this experiment are shown in this paper.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.847-854
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• 2022

The aim of this study is to develop a Named Entity Recognition (NER) model to automatically identify construction-related organizations from news articles. This study collected news articles using web crawling technique and construction-related organizations were labeled within a total of 1,000 news articles. The Bidirectional Encoder Representations from Transformers (BERT) model was used to recognize clients, constructors, consultants, engineers, and others. As a pilot experiment of this study, the best average F1 score of NER was 0.692. The result of this study is expected to contribute to the establishment of international business strategies by collecting timely information and analyzing it automatically.