• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.487-488
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• 2009

• 보건행정학회지
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• 제23권4호
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• pp.387-396
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• 2013

Background: The purpose of this study was to analyze the association between areas of Korea Train Express (KTX) region and external medical service use in Korean society using spatial statistical model. Methods: The data which was used in this study was extracted from 2011 regional health care utilization statistics and health insurance key statistics from National Health Insurance Corporation. A total spatial units of 229 districts (si-gun-gu) were included in this study and spatial area was all parts of the country excepted Jeju, Ulleungdo island. We conducted Kruskal-Wallis test, correlation, Moran's I and hot-spot analysis. And after, ordinary linear regression, spatial lag, spatial error analysis was performed in order to find factors which were associated with external medical service use. The data was processed by SAS ver. 9.1 and Geoda095i (windows). Results: Moran's I of health insurance patients' external medical service use was 0.644. Also, population density, Seoul region, doctor factors positively associated with health insurance patients' external medical service. In contrast, average age, health care organization per 100 thousand were negatively associated with health insurance patients' external medical service use. Conclusion: The finding of this study suggested that health insurance patient's external medical service use correlated for seoul region in korea. The study results imply the need for more attention medical needs in the region (si-gun-gu unit) for health insurance patients of seoul region. It is important to adapt strategy to activation of primary health care as well as enhancing public health institution for prevent leakage of patients to other areas.

• 전기학회논문지
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• 제63권4호
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• pp.589-595
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• 2014

The error of instrument transformers is measured by connecting the external burden with the secondary terminal of the instrument transformers. Because the error of transformer is affected by the apparent power and power factor of the external burden, an accurate measurement of burden is important for transformer evaluation. We have developed the burden evaluation equipment for both potential transformer and current transformer by employing the series resistor in the range of $20m{\Omega}{\sim}5{\Omega}$ and the parallel resistor in the range of $1M{\Omega}{\sim}500{\Omega}$, respectively, together with visual basic program. We could reduce testing time more than 5 times by employing method developed in this study, compared with that developed in past. This method shows more better reliability by analyzing the evaluation results and fitting graphs of burden measurements. The test results of the developed system is compared with those obtained in the power meter analyzer to verify the validity.

• 전자공학회논문지B
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• 제31B권11호
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• pp.163-169
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• 1994

본 논문에서는 기존의 循環神經回路網에서의 學習性能을 개선하고 局部최소해 문제를 해결하기 위한 노력의 일환으로서 附加적인 피드백 연결을 가진 순환신경회로망과 그 학습 알고리듬을 제안하였다. 이 방법에서는 회로망은 한번 반복하는동안 고정된 연결 가중치를 가지고, 주어진 時變人力과 初期條件下에서 주어진 週期동안 동작한다. 가중치는 最急降下法에 의해 총에너지가 가장 많이 감소하는 방향으로 변화된다. 만일 이러한 과정을 일정 반복횟수동안 수행한 후에도 에너지가 충분히 감소하지 않으면, 附加적인 피드백 연결이 도입되고 회로망의 외부입력이 주어진 식에 따라 다시 정의된다. 또한 제안된 회로망의 응용으로서 한국어 숫자음 인식에 대한 실험을 행하였다.

• 한국정밀공학회지
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• 제26권12호
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• pp.78-84
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• 2009

When external force is applied to humanoid robot's head, humanoid robot's neck is rotated to prevent the damage of it. So, robot's neck have to perceive forces (Fx of x-direction, Fy of y-direction and Fz of z-direction) and moments (Mx of x-direction, My of y-direction and Mz of z-direction) using the attached 6-axis force/moment sensor. Thus, in this paper, 6-axis force/moment sensor was developed to sense the forces and moments applied to robot's head. The structure of 6-axis force/moment sensor was modeled newly, and it was designed using FEM software (ANSYS) and manufactured by attaching straingages on the sensing element, finally, the characteristic test of the sensor was carried out. As a result, it is confirmed that interference error is less than 3%. And, it is thought that the sensor can be used to measure the forces and the moments for humanoid robot's head.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 춘계학술대회
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• pp.129-131
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• 1993

A transcutaneoos information transmission system using transmitted infrared light for an implantable total artificial heart(TAH) an developed and the performance of the system was tested. In an in vitro test, transmittance of the developed system was measured through various thicknesses of pig shins. In an in vivo test, a loopback test using a personal computer was performed to determine the error rate and an experiment using a mock system was taken. In this experiment, within acceptable lateral and vertical displacements, the error rate of at least 3.8E-6 was guaranteed. Monitoring signals from the internal controller(Intel 87C196) of the mock system were successfully transmitted to the external controller(IBM PC) and the operating commands from the external controller were successfully conducted by the mock system. Communication was done in half duplex mode according to RS-232 protocol at the speed of 4800 bps.

• 한국해양공학회지
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• 제11권3호
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• pp.170-179
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• 1997

This paper presents a hybrid navigation system for AUV to locate its position precisely in rough sea. The tracking system is composed of various sensors such as an inclinometer, a tri-axis magnetometer, a flow meter, and a super short baseline(SSBL) acoustic position tracking system. Due to the inaccuracy of the attitude sensors, the heading sensor and the flowmeter, the predicted position slowly drifts and the estimation error of position becomes larger. On the other hand, the measured position is liable to change abruptly due to the corrupted data of the SSBL system in the case of low signal to noise ratio or large ship motions. By introducing a sensor fusion technique with the position data of the SSBL system and those of the attitude heading flowmeter reference system (AHFRS), the hybrid navigation system updates the three-dimensional position robustly. A Kalman filter algorithm is derived on the basis of the error models for the flowmeter dynamics with the use of the external measurement from the SSBL. A failure detection algorithm decides the confidence degree of external measurement signals by using a fuzzy inference. Simulation is included to demonstrate the validity of the hybrid navigation system.

• 한국정보전자통신기술학회논문지
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• 제16권6호
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• pp.472-477
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• 2023

본 논문에서는 쿼드콥터 드론이 동적인 외부 환경 아래서도 외란에서도 효과적으로 경로를 추종하고 비행 안전성을 유지할 수 있도록 모델 예측 제어(MPC) 기법을 제안한다. MATLAB/Simulink에서 수행된 시뮬레이션을 통해, 외란이 주어지는 비행 시나리오에서 PID와 MPC 두 제어기의 성능을 비교한다. 제안된 설계 방법으로 MPC 제어기가 압력 변화와 공기 밀도 변동과 같은 외란에 대하여 MPC와 PID 제어기의 성능을 비교했을 때에 쿼드콥터 드론의 입력받은 주행 경로와 실제 경로의 Mean Squared Error 수치가 외란을 주기 전에는 0.2의 성능 차이를 보였다. 그리고, 외란을 주었을 때에는 0.8을 차이를 보이며 MPC 제어기의 향상된 경로 추종 정확도를 보여준다.

• 한국전자통신학회논문지
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• 제19권2호
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• pp.437-444
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• 2024

회전형 관성항법시스템은 IMU(: Inertial Measurement Unit)를 김블 위에 장착하고 김블을 규칙적으로 회전시켜 IMU의 오차를 상쇄시킴으로써 보다 정확한 항법 정보를 제공할 수 있다. 그러나 파도에 의해 자세 변화가 생기면 회전절차의 한 주기가 끝나는 시점에 자세 오차가 0으로 상쇄되지 않게 되어 큰 위치 오차를 유발한다. 본 논문에서는 이 문제를 고려하여 항체의 롤각 정보를 기반으로 외부 김블을 회전시켜 안정화를 시키는 방법을 제안한다. 시뮬레이션을 기반으로 파도에 의한 영향을 분석하고 외부 김블 안정화의 성능을 검증한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.528-550
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• 2024

Warehousing demand prediction is an essential part of the supply chain, providing a fundamental basis for product manufacturing, replenishment, warehouse planning, etc. Existing forecasting methods cannot produce accurate forecasts since warehouse demand is affected by external factors such as holidays and seasons. Some aspects, such as consumer psychology and producer reputation, are challenging to quantify. The data can fluctuate widely or do not show obvious trend cycles. We introduce a new model for warehouse demand prediction called MAGRU, which stands for Multi-layer Attention with GRU. In the model, firstly, we perform the embedding operation on the input sequence to quantify the external influences; after that, we implement an encoder using GRU and the attention mechanism. The hidden state of GRU captures essential time series. In the decoder, we use attention again to select the key hidden states among all-time slices as the data to be fed into the GRU network. Experimental results show that this model has higher accuracy than RNN, LSTM, GRU, Prophet, XGboost, and DARNN. Using mean absolute error (MAE) and symmetric mean absolute percentage error(SMAPE) to evaluate the experimental results, MAGRU's MAE, RMSE, and SMAPE decreased by 7.65%, 10.03%, and 8.87% over GRU-LSTM, the current best model for solving this type of problem.