• 반도체디스플레이기술학회지
• /
• 제21권2호
• /
• pp.112-116
• /
• 2022

The demand for a rear reflective material is continuing according to the expansion of the bifacial soar module and the effect on the re-reflection of the ground using a back sheet that is not used due to the increase in the supply of the bifacial solar module was confirmed. For analysis, a bifacial solar module with an output of 445W was connected to a single inverter of 49.84kW, and analysis of each two inverters was carried out. In the analysis of the results, it was confirmed that the generation amount increased by 5.25% compared to the case where the back sheet reflective film was not installed and it was confirmed that the increase in the generation amount was the noon time when strong solar radiation was irradiated, not the time of sunrise and sunset.

• 한국터널지하공간학회 논문집
• /
• 제18권6호
• /
• pp.545-556
• /
• 2016

운영 중 해저 터널의 안정성 평가에 다양한 계측 정보를 사용해서 역해석하면, 효율적인 오차율 이내의 결과를 획득할 수 있다. 선행 연구에서 검증된 차분진화 알고리즘 기반의 역해석 수행 시 FLAC3D 등 범용 지반해석 프로그램을 사용했지만, 상대적으로 해석시간이 오래 걸리고, 제어가 어려운 단점이 있다. 이러한 이유로, 상대적으로 해석시간이 짧게 소요되는 beam-spring 모델기반의 FEM solver를 Python 언어로 개발하여, 기구축된 차분진화 알고리즘과 결합하였다. 계측 데이터로부터 실시간에 가깝게 운영 중 터널의 안정성 평가가 가능할 것으로 판단되며, 우선 솔버 개발에 용이한 종단방향 터널에 대해서 프로그램을 개발하였다.

• 한국재난정보학회 논문집
• /
• 제16권1호
• /
• pp.1-9
• /
• 2020

연구목적: 본 연구에서는 수치해석을 통한 역해석기법을 이용 현장변위예측관리기법을 보완하는 안전관리 방안에 대한 연구를 수행하였다. 연구방법: 역해석기법을 이용하여 유한요소해석 기반인 MIDAS GTS/NX 프로그램을 이용 해석을 수행하였다. 붕괴현장의 계측데이터와 변위 경향을 가능한 근접시킨 뒤, 붕괴원인을 추정 후 붕괴방지 공법을 적용하였다. 연구결과: 역해석을 수행하여 얻은 결과물중 하나인 지반정수로 붕괴원인을 추정한 결과 앵커의 자유장 길이 불충분으로 확인 되었고, 붕괴방지 공법으로 앵커의 자유장 길이를 변화시켰으며, 변위가 현저히 감소되는 것을 확인할 수 있었다. 결론: 역해석기법을 현장관리에 참고, 붕괴원인을 추정하고 합리적인 붕괴방지 대책을 제시할 경우 붕괴 사고를 줄이는데 도움이 될 것이다.

• The Korean Journal of Pain
• /
• 제31권1호
• /
• pp.27-38
• /
• 2018

Background: Related to escalating health care costs and the questionable effectiveness of multiple interventions including lumbar facet joint interventions, cost effectiveness or cost utility analysis has become the cornerstone of evidence-based medicine influencing coverage decisions. Methods: Cost utility of therapeutic lumbar facet joint nerve blocks in managing chronic low back pain was performed utilizing data from a randomized, double-blind, controlled trial with a 2-year follow-up, with direct payment data from 2016. Based on the data from surgical interventions, utilizing the lowest proportion of direct procedural costs of 60%, total cost utility per quality adjusted life year (QALY) was determined by multiplying the derived direct cost at 1.67. Results: Patients in this trial on average received $5.6{\pm}2.6$ procedures over a period of 2 years, with average relief over a period of 2 years of $82.8{\pm}29.6$ weeks with $19{\pm}18.77$ weeks of improvement per procedure. Procedural cost for one-year improvement in quality of life showed USD $2,654.08. Estimated total costs, including indirect costs and drugs with multiplication of direct costs at 1.67, showed a cost of USD $4,432 per QALY. Conclusions: The analysis of therapeutic lumbar facet joint nerve blocks in the treatment of chronic low back pain shows clinical effectiveness and cost utility at USD $2,654.08 for the direct costs of the procedures, and USD $4,432 for the estimated overall cost per one year of QALY, in chronic persistent low back pain non-responsive to conservative management.

• 전력전자학회논문지
• /
• 제21권5호
• /
• pp.449-452
• /
• 2016

This paper presents a simplified analysis on the rotor position detection error in sensorless interior permanent magnet brushless DC motor (BLDCM) drives, wherein terminal voltage sensing based on the back-electromotive force (back-EMF) zero-crossing point detecting circuitry is employed. The effect of a rotor saliency on the back-EMF's zero-crossing point detection is analyzed using the extended EMF-based voltage equation of the interior permanent BLDCM in a stationary reference frame, and thus the overall analysis is considerably simplified compared to the conventional one. Simulation results are provided to verify the effectiveness of the proposed method.

• 터널과지하공간
• /
• 제12권1호
• /
• pp.37-42
• /
• 2002

본 연구에서는 터널의 주요 설계정수인 탄성계수와 측압계수를 산정 할 수 있는 역 해석 알고리즘을 개발하였다. 해석 알고리즘은 범용 유한차분해석 프로그램인 FLAC의 해석과정 내에 직접탐색법 알고리즘을 이용한 FISH 문을 삽입함으로써 구성하였다. 기존 연구에서 사용한 탄성모델에 대하여 본 연구에서 개발한 역 해석 알고리즘의 적합성을 검토하였다. 본 연구에서 개발된 역 해석 알고리즘은 기존 역 해석 기법에 비해 더 적은 반복연산에 더 정확한 결과를 얻을 수 있음을 확인하였다.

• Industrial Engineering and Management Systems
• /
• 제16권1호
• /
• pp.103-108
• /
• 2017

Tourism is a sector that plays an important role in the economic growth of Indonesia. Bandung as the capital of West Java province is known as the city with diverse tourism potential, both in the attractiveness of the city and surrounding natural beauty. DHR is a three stars resort hotel in the city with a strategic location. As a three stars resort hotel, DHR has been experiencing occupancy rate problems, consequently, it cannot often reach the set targets, both during high season and low season. The purpose of this study is to identify the factors of hotel performance that influences consumer staying back decision in the future. Questionnaires have been distributed to hotel guests to gather information regarding their interest and the performance assessment of the hotel services and facilities, and staying back decision in the future. Discriminant Analysis and Hypothesis Testing are used to determine which hotel performance variables will directly affect consumer staying back decision. The result of this study provide marketing strategy that should be implemented by the hotel management in order to increase its occupancy rate.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제49권6호
• /
• pp.380-386
• /
• 2000

This paper presents the mathematical modelling analysis of Brushless Synchronous Motor(BLSM). The dynamic and the steady state characteristics of BLSM are simulated and analyzed : electromagnetic torque, speed, line voltage, and current. We used mathematical modelling to model of BLSM with sinusoidal back EMF, namely the shaft transformation referencing rotor frame from a, b, c three to produce constant torque like synchronous motor. The experiment result has already similar to compare with simulation result : torque error about 7%, speed error about 5%. The validity of proposed modelling and analysis was confirmed by the experimental result.

• 터널과지하공간
• /
• 제1권2호
• /
• pp.204-217
• /
• 1991

In this study, the elastic modulus and the initial stresses of the rock were calculated through back analysis of in-situ displacements measured during excavation of the underground caverns. Results from back analysis were employed to determine the redistributed stresses the displacements and relaxed zone in the rock around the caverns, which supplement the geological characterization results. To verify the reliability of the back analysis program the elastic modulus and the initial stresses were obtained from inputting the displacements calculated by FEM. These were compared with the assumed normalized stresses in FEM and were in a reasonable agreement with an error of more or less than 3%.

• 소성∙가공
• /
• 제17권5호
• /
• pp.350-355
• /
• 2008

Currently, in the automotive industry, the efforts to reduce the manufacturing cost by changing the manufacturing process are continually performed. In this paper, we proposed a new manufacturing process, the roll bending process of a ring plate of automotive fuel tank instead of conventional press blanking process to reduce material loss and manufacturing cost. Finite element analysis was used to optimize the roll bending process to assure rectangular cross-section of the ring plate. Also, spring-back analysis after the roll bending process was performed and dimension of the bending die considering spring-back was analyzed. Finally, we verified a possibility for realization of the proposed method with prototypes.