• 한국자동차공학회논문집
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• 제19권3호
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• pp.57-64
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• 2011

In general, the durability performance of a large-sized military truck has been checked through a field durability test which required many man-hours and costs. To reduce these expenses, the durability analysis using a VTL(Virtual Test Lab) at an initial design stage was introduced recently. In this paper, the VTL with a multi-post testrig template for a large-sized truck was developed to compute the load histories transferred to cabin and chassis frame. The VTL consisted of trimmed FE models of cabin, chassis frame, and deck, dynamic models of front and rear suspensions, and a 8-post testrig template. The basic characteristics of the VTL were correlated with experimental results which had been extracted from actual driving test, modal test, and static weight test. The fatigue analysis using MSM(Modal Superposition Method) was applied to evaluate the durability performance of a large-sized military truck. From a series of analytic methods, it is shown that the fatigue analysis process using the VTL could be a useful tool to estimate the fatigue lives and weak areas of a large-sized military truck.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.229-233
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• 2019

Large-scale High Temperature Superconducting (HTS) wind power generators suffer from high electromagnetic force and high torque due to their high current density and low rotational speed. Therefore, the torque and Lorentz force of HTS wind power generators should be carefully investigated. In this paper, we proposed a Performance Evaluation System (PES) to physically test the structural stability of HTS coils with high torque before fabricating the generator. The PES is composed of the part of a pole-pair of the HTS generator for estimating the characteristic of the HTS coil. The 10 MW HTS generator and PES were analyzed using a 3D finite element method software. The performance of the HTS coil was evaluated by comparing the magnetic field distributions, the output power, and torque values of the 10 MW HTS generator and the PES. The magnetic flux densities, output power, and torque values of the HTS coils in the PES were the same as a pole-pair of the 10 MW HTS generator. Therefore, the PES-based evaluation method proposed in this paper can be used to estimate the critical characteristics of the HTS generator under high magnetic field and high torque before manufacturing the HTS wind turbines. These results will be used effectively to research and manufacture large-scale HTS wind turbine generators.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제45차 학술발표회
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• pp.13-13
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• 2011

Hair luster is a key objective for consumers in the hair care market. Recently, as consumers using hair coloring or bleaching product increase, measurement and quantification of hair luster become more important. A hair visual appearance measurement system called SAMBA can quantitate the luster and effectively separate specular and diffuse light. SAMBA usually has been employed to measure, mainly with the change of shine value, effects of cosmetic treatments on hair shine and surface smothness. We conducted a study on the effect of dyeing and bleaching on the luster, as a result, a strong bleaching caused large decline of the luster. But the large decline of luster was caused by increasing intensity of diffusion and width of chroma peak, not the shine value. The system of dye toning for higher luster can be developed on reference to the peak type of chroma and diffusion depends on kinds and combination of dye.

• 한국물환경학회지
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• 제21권3호
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• pp.219-229
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• 2005

The analytical methods for dioxins in water sample from wastewater to tap water were reviewed. For extraction method, liquid-liquid extraction (LLE) has been widely used, however, this process needs too much time and man power. New approach including solid phase extraction (SPE) is now applicable to large volume of water sample with high extraction efficiency. Column clean up in classical analytical methods were very complex and time consuming procedures during decade. Modifications were tried to decrease solvent and reagents volume. Moreover, use of column connection method has been demonstrated in the environmental matrices. Instrumental configurations also have been improved, in which GC/MS/MS with large volume injection approach can analyze picogram levels. Absolute sensitivities of HRMS increased compared to old versions of double focusing sector type mass spectrometers. Based on these analytical evolutions during last 10 years, we tried to optimize the analytical method for dioxins in water sample from sample extraction to instrumental analysis.

• 한국군사과학기술학회지
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• 제27권1호
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• pp.60-69
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• 2024

The importance of geospatial information is increasingly highlighted in the defense domain. Accurate and up-to-date geospatial data is essential for situational awareness, target analysis, and mission planning in millitary operations. The use of high-resolution geospatial data in military operations requires large storage and fast image processing capabilities. Efficient image processing is required for tasks such as extracting useful information from satellite images and creating 3D terrain for mission planning, In this paper, we designed a cloud-based operational situation mixed reality visualization system that utilizes large-scale geospatial information distributed processed on a cloud server based on the container orchestration platform Kubernetes. We implemented a prototype and confirmed the suitability of the design.

• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.121-125
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• 2016

KEPCO has completed the installation and demonstration of a 52 MW battery energy storage system (BESS) for frequency regulation. Especially, 24 MW BESS is for Automatic Generation Control (AGC) in Shin-Yongin substation. Recently, KEPCO Research Institute has operated it connected to EMS of KPX. This paper discussed the operation strategy of EMS through a study on using 24 MW BESS in AGC operation and propose the improvement of AGC target. It is expected that this paper helps a safe and reliable operation and control of ESS for AGC through its continuous update.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.130-137
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• 2010

Due to test facility and specialty, it is physically difficult to conduct the modal tests of large-sized structures such as truck, bus and airplane. So, in case of a large-sized truck, the mode analysis on a full vehicle model comprised of reliable cabin, frame, and deck has been generally performed. However, the reliability of overall vibrational characteristics of the analytic model has not been fairly guaranteed by the testified models of each subsystem owing to the existence of cab suspension and the nonlinear mounting between a chassis frame and a special deck system. In this paper, a method to find out the modal characteristics of a large-sized military truck is presented. New modal test equipment is developed to set the boundary conditions of three military truck variants as close as a free-free condition. And the mode analysis method using coupled structure and dynamic models is established to consider the above-mentioned dynamic non-linearities of the vehicle itself. The usefulness of the suggested method is verified by comparing with the modal test results. Finally, the modal parameters of the final variant are extracted using the proved analytic method.

• KEPCO Journal on Electric Power and Energy
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• 제5권4호
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• pp.343-347
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• 2019

When referring to weight, volume, and efficiency, a SuperConducting Synchronous Generator (SCSG) is definitely superior to conventional generators as a large-scale wind power generation system. The SCSG is connected to a full power converter that transmits the energy from the SCSG to the power grid. To reduce the current stress and system cost, the SCSG which has nine-phase armature windings with three converters is used. This paper deals with a comparative analysis of 10 MW superconducting wind power generators with three-phase and nine-phase armature windings. The stator windings of SCSGs are of various types. Using the finite element method, SCSGs are analyzed and compared in terms of the weight and volume of SCSGs, the total length of the superconducting wire, harmonics, torque performance, and efficiency. The analyzed results will be effectively utilized to design large-scale superconducting generators for wind power generation systems.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.73-77
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• 2015

Offshore wind farms extend a distance from an onshore grid to increase their generating power, but long distance and high power transmissions raise a lot of cost challenges. LFAC (Low Frequency AC) transmission is a new promising technology in high power and low cost power transmission fields against HVDC (High Voltage DC) and HVAC (High Voltage AC) transmissions. This paper presents an economic comparison of LFAC and HVDC transmissions for large offshore wind farms. The economic assessments of two different transmission technologies are analyzed and compared in terms of wind farm capacities (600 MW and 900 MW) and distances (from 25 km to 100 km) from the onshore grid. Based on this comparison, the economic feasibility of LFAC is verified as a most economical solution for remote offshore wind farms.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2023년도 제35회 한글 및 한국어 정보처리 학술대회
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• pp.289-294
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• 2023

대형 언어 모델(Large Language Model)은 방대한 데이터와 파라미터를 기반으로 문맥 이해에서 높은 성능을 달성하였지만, Human Alignment를 위한 문장 생성 제어 연구는 아직 활발한 도전 과제로 남아있다. 본 논문에서는 Instruction Tuning을 통한 문장 생성 제어 실험을 진행한다. 자연어 처리 도구를 사용하여 단일 혹은 다중 제약 조건을 포함하는 Instruction 데이터 셋을 자동으로 구축하고 한국어 언어 모델인 Polyglot-Ko 모델에 fine-tuning 하여 모델 생성이 제약 조건을 만족하는지 검증하였다. 실험 결과 4개의 제약 조건에 대해 평균 0.88의 accuracy를 보이며 효과적인 문장 생성 제어가 가능함을 확인하였다.