• 한국전문물리치료학회지
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• 제16권2호
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• pp.16-23
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• 2009

The purpose of this study was to investigate the effects postural changes on respiratory muscles and acoustic parameters of the children with spastic cerebral palsy. Nine children with spastic cerebral palsy who required assistance when walking were selected. The ages of the children ranged from 6 to 9 years old. The phonation of the sustained vowel /a/ and the voice qualities of each child such as fundamental frequency($F_0$; Hz), pitch variation (Jitter; %), amplitude variation (Shimmer; %) and noise to harmonic ratio (NHR) were analyzed by Multi-Dimensional Voice Program (MDVP). The muscle activity of three major respiratory muscles: pectoralis major muscle, upper trapezius muscle and rectus abdorminalis muscle, were measured by examining the root mean square (RMS) of the surface EMG to investigate the impact of changes in the adjusted sitting posture of each subject. However, the RMS of pectoralis major muscle showed a significant differences (p<.05). Secondly, there were no significant differences in $F_0$, Jitter and Shimmer between pre and post posture change, but there was a significant difference in NHR (p<.05). The data were collected in each individual; once prior and once after the sitting posture change. The data were analyzed by Wilcoxon signed ranks-test using SPSS version 14.0 for Windows. The findings of this study were as follows; Firstly, the RMS of upper trapezius and rectus abdorminalis muscle were not significant different between pre and post sitting posture changes. From the result, it is concluded that changes in the adjusted sitting posture decreases the abnormal respiratory patterns in the children with spastic cerebral palsy which is characterized by the hyperactivity of the respiratory muscles in breathing. Also, there is increased on the voice qualities in children with spastic cerebral palsy.

• 디지털콘텐츠학회 논문지
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• 제18권4호
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• pp.733-738
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• 2017

21세기 화두는 위험사회에서 체감하고 있는 범죄에 대한 불안과 공포에 대하여 범죄를 예방함으로써 안전사회를 구축하는 것이다. 그럼에도 불구하고 최근 질적, 양적인 측면에서 학교폭력, 묻지마 범죄, 층간소음범죄 등과 관련된 강력범죄가 꾸준히 증가추세에 있다. 이에 따라 법제도적 개선방안으로써 환경범죄학(Environmental Criminology)에서 바라 본 범죄예방 도구이자 전략인 CPTED가 하나의 대안으로 부각되고 있다. 국토교통부는 범죄예방 기준인 '범죄예방 건축기준 고시'를 2015년부터 시행하고 있으며 현대 위험사회에서 강력범죄 및 경범죄의 사전예방을 위해서는 사회 안전시스템 구축이 요구된다. 제한된 경찰력이라는 물리적 한계를 극복하기 위한 대안으로 환경설계를 통해 범행기회를 심리적, 물리적으로 차단하는 정책을 모색함으로써 범죄예방에 접근할 필요가 있다.

• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.436-441
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• 2014

We have demonstrated an amplified wavelength-division multiplexed (WDM) passive optical network (PON) by using broadband light source (BLS) seeded optical sources and chirped fiber Bragg gratings (FBGs) based dispersion compensators. Chirped FBGs located at central office (CO) were fabricated and used as channel-by-channel dispersion compensators in order to mitigate the dispersion-induced distortion of both downstream and upstream signals. Owing to a low insertion loss of chirped FBG based dispersion compensator, the optical signal-to-noise ratio (OSNR) of the downstream signal could be improved to be ~28 dB. Thus, we re-confirmed that an error-free transmission of 1.25 Gb/s signals over a 100 km single-mode fiber (SMF) link could be achieved with a proposed amplified WDM-PON architecture. We have also evaluated the impact of various noises on the system's performance, and found that the low OSNR of the downstream signal would be a main limiting factor on the maximum reach of the proposed amplified WDM-PON architecture. From the measured ~13 dB improvement in OSNR of the downstream signal compared to our previously-proposed dispersion compensating module based scheme, we believe that the proposed architecture can accommodate a reach of longer than 100 km SMF link easily.

• 한국철도학회논문집
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• 제15권2호
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• pp.141-146
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• 2012

차륜과 레일의 반복적인 구름접촉은 레일 표면결함을 유발하고, 레일 표면결함은 충격하중을 유발하여 소음 진동, 레일파단, 궤도파괴로 이어지고 심할 경우 열차사고(탈선)를 발생할 수 있다. 이러한 레일 표면결함을 제어하기 위한 방법으로 레일연마가 시행되고 있다. 본 연구는 KTX차륜과 UIC레일에서 발생하는 최대 접촉압력을 유한요소해석을 통해 산정하였고, 일반레일 및 열처리레일에 대한 구름접촉피로시험을 수행하여 접촉압력 및 반복횟수에 따른 레일표면 경화층 형성 경향을 분석하였으며, 누적통과톤수에 따라 고속철도 레일에서 발생하는 표면 경화층을 제거하여 건전한 레일표면을 유지하기 위해 0.2mm/2천만톤의 적정 레일연마량을 제안하였다.

• 한국ITS학회 논문지
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• 제16권4호
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• pp.107-121
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• 2017

본 연구에서는 군집주행환경에서 비자율차의 행태분석을 위해 영상기반의 조사를 통해 피실험자의 인적특성과 군집주행 인지여부를 조사하고, 주행 시뮬레이션 실험을 통해 비자율차의 차량거동을 수집했다. 또한, 주행 시뮬레이션 실험 후 NASA-TLX 설문조사를 통해 작업부하점수를 조사했다. 영상기반 인지특성 조사 결과 피실험자 대부분이 군집주행 중인 차량들을 인지하고 군집 차량군으로 인해 부담감을 느끼는 것으로 나타났다. 군집주행환경에서의 평균속도가 비군집주행환경일 때보다 낮게 나타났고, 평균속도의 표준편차는 군집주행환경일 때 더 높게 나타났다. 인적특성과 작업부하점수를 연계분석한 작업부하평가 결과 군집, 비군집주행환경 시 인적특성별로 작업부하점수가 통계적으로 유의한 차이가 나타나는 결과들을 확인했다. 인적특성과 차량거동을 연계분석한 차량거동평가 결과에서도 군집, 비군집주행환경 시 통계적으로 유의한 차이가 나타나는 결과들을 확인했다. 본 연구의 결과를 고령운전자, 여성 등 고위험군 운전자의 안전성 증대, 비자율차 운전자에게 주변 군집주행차량에 대한 정보 제공 방안 모색 등의 비자율차 운전자를 위한 교통관리전략을 수립하는데 활용할 수 있을 것이라 판단된다.

• 한국추진공학회지
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• 제5권4호
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• pp.31-39
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• 2001

복합재료로 제작이 되는 수송기계용 추진축은 진동, 소음, 중량 등을 감소시킬 수 있는 장점을 가진다. 본 연구에서는 유한요소법을 이용하여 카본/에폭시 복합재료로 구성된 추진축을 설계하였으며 필라멘트 와인딩 방법을 사용하여 시험용 시편을 제작하였다. 유한요소법을 이용한 추진축의 설계 방법의 정확성을 확인하고자 FFT 해석기와 충격해머를 이용한 고유진동수 측정시험과 임계회전속도 측정 실험 장비를 이용한 임계회전속도 측정시험을 수행하였다. 해석결과와 시험결과를 비교하였을 때 오차율은 3.4%이하로 해석결과의 신뢰성을 확인하였다. 이러한 FEM 설계방법을 이용하여 추진 축의 진동 및 강도특성에 영향을 미치는 요인들에 대한 연구를 수행하였다 여러 요인들 중 중량의 증가 없이 고유진동수 변화에 가장 큰 영향을 미치는 것은 와인딩 각도임을 확인하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권4호
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• pp.301-311
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• 2016

This paper describes the whole procedures to determine ice-induced global loads on the ship using measured full-scale data in accordance with the method proposed by the Canadian Hydraulics Centre of the National Research Council of Canada. Ship motions of 6 degrees of freedom (dof) are found by processing the commercial sensor signals named Motion Pak II under the assumption of rigid body motion. Linear accelerations as well as angular rates were measured by Motion Pak II data. To eliminate the noise of the measured data and the staircase signals due to the resolution of the sensor, a band pass filter that passes frequencies between 0.001 and 0.6 Hz and cubic spline interpolation resampling had been applied. 6 dof motions were computed by the integrating and/or differentiating the filtered signals. Added mass and damping force of the ship had been computed by the 3-dimensional panel method under the assumption of zero frequency. Once the coefficients of hydrodynamic and hydrostatic data as well as all the 6 dof motion data had been obtained, global ice loads can be computed by solving the fully coupled 6 dof equations of motion. Full-scale data were acquired while the ARAON rammed old ice floes in the high Arctic. Estimated ice impact forces for two representative events showed 7e15 MN when ship operated in heavy ice conditions.

• 한국컴퓨터정보학회논문지
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• 제12권1호
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• pp.57-65
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• 2007

서로 다른 형태와 크기를 가지는 탐색패턴과 움직임 벡터의 분포는 고속 블록 정합 알고리즘에서 탐색 속도와 화질을 좌우하는 중요한 요소이다. 본 논문에서는 새로운 고속 블록 정합 알고리즘 개발을 위해 기존의 다이아몬드패턴과 육각패턴의 단점을 해결할 수 있는 납작한 육각패턴을 제안한다. 제안하는 알고리즘은 움직임이 큰 벡터에 대해서 납작한 육각패턴을 이용하여 고속으로 움직임 벡터를 찾게 하였다. 실험 결과를 통해 제안된 납작한 육각패턴 탐색 알고리즘은 다이아몬드패턴 탐색 알고리즘이나 육각패턴 탐색 알고리즘에 비하여 움직임 벡터 추정의 속도에 있어서 약 $0.4{\sim}21.3%$의 성능 향상을 보였으며 화질 또한 PSNR 기준으로 약 $0.009{\sim}0.531dB$의 성능 향상을 보였다.

• 대한산업공학회지
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• 제40권2호
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• pp.223-232
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• 2014

Life-cycle assessment (LCA) is often employed to quantify the environmental impact of a product in a comprehensive manner. The aspects of performance and usability as well as that of eco-friendliness should be considered in an integrated manner for the market competitiveness of an eco-friendly product. The present study developed a product improvement plan for an eco-friendly electric heater by benchmarking two small-size electric heaters (companies 'H' and 'T') in terms of performance, usability, and eco-friendliness. The performance measurements such as temperature, humidity, wind speed, noise, and power consumption were collected while the two heaters were operated in a laboratory setting. Then, the usability evaluations such as aesthetics, operation satisfaction, performance satisfaction, and overall satisfaction were surveyed for the two heaters using a 5-point scale (1 for very unsatisfied and 5 for very satisfied). Lastly, the LCA analysis was conducted by following the six-step process of eco-friendly product design provided by KEITI. The analysis results of the two products being integrated with the aspects of product, service, and user, four design improvement directions such as eco-efficient, smart, modularized, and user-support were recommended for an eco-friendly electric heater. These proposed concepts would be useful to develop an eco-friendly electric heater design with a high level of market competitiveness.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.277-282
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• 2006

It is well known that Kalman filtering is an optimal real-time data fusion method for GPS/INS integration. However, it has some limitations in terms of stability, adaptability and observability. A Kalman filter can perform optimally only when its dynamic model is correctly defined and the noise statistics for the measurement and process are completely known. It is found that estimated Kalman filter states could be influenced by several factors, including vehicle dynamic variations, filter tuning results, and environment changes, etc., which are difficult to model. Neural networks can map input-output relationships without apriori knowledge about them; hence a proper designed neural network is capable of learning and extracting these complex relationships with enough training. This paper presents a GPS/INS integrated system that combines Kalman filtering and neural network algorithms to improve navigation solutions during GPS outages. An Extended Kalman filter estimates INS measurement errors, plus position, velocity and attitude errors etc. Kalman filter states, and gives precise navigation solutions while GPS signals are available. At the same time, a multi-layer neural network is trained to map the vehicle dynamics with corresponding Kalman filter states, at the same rate of measurement update. After the output of the neural network meets a similarity threshold, it can be used to correct INS measurements when no GPS measurements are available. Selecting suitable inputs and outputs of the neural network is critical for this hybrid method. Detailed analysis unveils that some Kalman filter states are highly correlated with vehicle dynamic variations. The filter states that heavily impact system navigation solutions are selected as the neural network outputs. The principle of this hybrid method and the neural network design are presented. Field test data are processed to evaluate the performance of the proposed method.