• Title/Summary/Keyword: error characteristics

Search Result 3,501, Processing Time 0.03 seconds

A Study on the Importance and Application of 3D Printing Technology for Street Furniture Manufacturing (거리 가구 제작을 위한 3D 프린팅 기술 중요도 도출 및 적용 방안에 관한 연구)

  • Lee, Sung Ho;Lee, Tae Hee;Lim, Hyun Su
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.21 no.4
    • /
    • pp.509-517
    • /
    • 2020
  • This study evaluated the importance of technical characteristics in manufacturing street furniture using 3D printing technology to suggest the direction of development of high priority 3D printing technology. The importance was analyzed by the QFD, quantified by scores and the priority of the items was summarized. As a result, the 'output size', 'shrinkage of material', and 'output angle' were derived as technical elements that should be prioritized in development and research. For verification, the design of atypical street furniture was made into a large 3D printed output and the development direction was suggested by applying the technical elements of priority during the manufacturing process. Street furniture should be designed based on functionality and stability, as well as economic efficiency, productivity, and aesthetics. Therefore, the 'output size' ensured stability by minimizing the division of parts, and the 'contractability of materials' satisfied the aesthetic and productivity by minimizing the error of form. Finally, the 'output angle' was verified by improving the quality of the output and selecting an angle with efficient and structural stability through various output angles.

Abnormal Eye Movements in Patients with Dementia (치매 환자에서 나타나는 비정상적인 안구운동)

  • Kim, Hyun;Lee, Kang-Joon
    • Korean Journal of Psychosomatic Medicine
    • /
    • v.15 no.2
    • /
    • pp.73-80
    • /
    • 2007
  • Anumber of prior studies have reported eye movement dysfunction in patients with dementia. The eye movement test which is non-invasive can evaluate the local brain function quantitatively. Therefore, it can be a useful method for characterizing regional brain abnormalities of patients with dementia. The aim of this paper is to review the literatures on eye movement abnormalities in dementia patients. Saccade system dysfunctions in Alzheimer disease include increased latency, reduced accuracy, and increased antisaccade error rates. Patients with frontotemporal dementia showed impaired reflexive saccade inhibition and increased latency and errors of antisaccade task. And delayed initiation of voluntary saccades, slow saccades, and increased errors and latency on antisaccade task were found in Huntington's disease. Patients with Parkinson’s disease dementia and dementia with Lewy bodies have characteristics of impaired in both reflexive saccade execution and complex saccade performance. However, there were few reports of abnormal eye movements in Creutzfeldt-Jakob disease; they could be found at the later stages after symptoms of dementia came to be evident, and secondary to cerebellar and vestibular involvement. Slowing of saccades and hypometric saccades might precede the supranuclear limitation of vertical gaze in PSP. Dysfunction of voluntary eyelid movements was a characteristic finding of PSP as well. In conclusion, patients with dementia can show various abnormal eye movements and they are related with cortial and subcortical brain dysfunctions. The research on localization of brain relevant to each symptom can promise more clinical implications of eye movement of dementia.

  • PDF

Measurement of Rainfall using Sensor Signal Generated from Vehicle Rain Sensor (차량용 레인센서에서 생성된 센서시그널을 이용한 강우량 측정)

  • Kim, Young Gon;Lee, Suk Ho;Kim, Byung Sik
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.38 no.2
    • /
    • pp.227-235
    • /
    • 2018
  • In this study, we developed a relational formula for observing high - resolution rainfall using vehicle rain sensor. The vehicle rain sensor consists of eight channels. Each channel generates a sensor signal by detecting the amount of rainfall on the windshield of the vehicle when rainfall occurs. The higher the rainfall, the lower the sensor signal is. Using these characteristics of the sensor signal generated by the rain sensor, we developed a relational expression. In order to generate specific rainfall, an artificial rainfall generator was constructed and the change of the sensor signal according to the variation of the rainfall amount in the artificial rainfall generator was analyzed. Among them, the optimal sensor channel which reflects various rainfall amounts through the sensitivity analysis was selected. The sensor signal was generated in 5 minutes using the selected channel and the representative values of the generated 5 - minute sensor signals were set as the average, 25th, 50th, and 75th quartiles. The calculated rainfall values were applied to the actual rainfall data using the constructed relational equation and the calculated rainfall amount was compared with the rainfall values observed at the rainfall station. Although the reliability of the relational expression was somewhat lower than that of the data of the verification result data, it was judged that the experimental data of the residual range was insufficient. The rainfall value was calculated by applying the developed relation to the actual rainfall, and compared with the rainfall value generated by the ground rainfall observation instrument observed at the same time to verify the reliability. As a result, the rain sensor showed a fine rainfall of less than 0.5 mm And the average observation error was 0.36mm.

Tensile Deformation Characteristics of ECC Predicted with a Modified Fiber Bridging Curve (수정된 섬유 가교 특성을 고려한 ECC의 인장변형특성)

  • Kim, Jeong-Su;Lee, Bang-Yeon;Kim, Jin-Keun;Kim, Yun-Yong
    • Journal of the Korea Concrete Institute
    • /
    • v.21 no.5
    • /
    • pp.541-548
    • /
    • 2009
  • A theoretical prediction model of fiber bridging curve was established based on the assumption that fibers are uniformly distributed on the crack surface. However, the distance between fibers and their orientation with respect to crack surface can greatly affect the prediction of fiber bridging curve. Since, the shape of fiber bridging curve is a critical factor for predicting the tensile stress-strain relationship of ECC, it is expected that the assumption of uniform distribution of fiber may cause a significant error when predicting the tensile behavior of ECC. To overcome this shortcoming, a new prediction method of stress-strain relation of ECC is proposed based on the modified fiber bridging curve. Only effective fibers are taken into account considering the effects of their orientation and distance between them. Moreover, the approach for formulating the tensile stress-strain relation is discussed, where a procedure is presented for obtaining important parameters, such as the first crack strength, the peak stress, the displacement at peak stress, tensile strain capacity, and the crack spacing. Subsequent uniaxial tensile tests were performed to validate the proposed method. It was found that the predicted stress-strain relations obtained based on the proposed modified fiber bridging curve exhibited a good agreement with experimental results.

A $2{\times}2$ Microstrip Patch Antenna Array for Moisture Content Measurement of Paddy Rice (산물벼 함수율 측정을 위한 $2{\times}2$ 마이크로스트립 패치 안테나 개발)

  • 김기복;김종헌;노상하
    • Journal of Biosystems Engineering
    • /
    • v.25 no.2
    • /
    • pp.97-106
    • /
    • 2000
  • To develop the grain moisture meter using microwave free space transmission technique, a 10.5GHz microwave signal with the power of 11mW generated by an oscillar with a dielectric resonator is transmitted to an isolator and radiated from a transmitting $2{\times}2$ microstrip patch array antenna into the sample holder filled with the 12 to 26%w.b. of Korean Hwawung paddy rice. the microwave signal, attenuated through the grain with moisture, is collected by a receiving $2{\times}2$ microstrip patch array antenna and detected using a Shottky diode with excellent high frequency characteristic. A pair of light and simple microstrip patch array antenna for measurement of grain moisture content is designed and implemented on atenflon substrate with trleative dielectric constant of 2.6 and thickness of 0.54 by using Ensemble ver. 4.02 software. The aperture of microstrip patch arrays is 41 mm width and 24mm high. The characteristics of microstrip patch antenna such as grain. return loss, and bandwidth are 11.35dBi, -38dB and 0.35GHz($50^{\circ}$ at far-field pattern of E and H plane. The width of the sample holder is large enough to cover the signal between the antennas temperature and bulk density respectively. The calibration model for measurement of grain moisture content is proposed to reduce the effects of fluectuations in bulk density and temperature which give serious errors for the measurements . From the results of regression analysis using the statistically analysis method, the moisture content of grain samples (MC(%)) is expressed in terms of the output voltage(v), temperature (t), and bulk density of samples(${\rho}b$)as follows ;$$MC(%)\;=\;(-3.9838{\times}10^{-8}{\times}v^{3}+8.023{\times}10^{-6}{\times}v^{2}-0.0011{\times}v-0.0004{\times}t+0.1706){\frac{1}{{\rho}b}}{\times}100$ Its determination coefficient, standard error of prediction(SEP) and bias were found to be 0.9855, 0.479%w.b. and -0.0.369 %w.b. respectively between measured and predicted moisture contents of the grain samples.

  • PDF

A Study on Evaluation of LED Lighting Environments for Energy Saving and Work Effectiveness (에너지 저감과 업무 효율성을 위한 LED 조명환경 평가에 대한 연구)

  • Kim, Hyung-Sun;Lim, Jae-Hyun;Lee, Kee-Sun;Kim, Kil-Hee;Jung, Hee-Chang;Kim, Jin Ho
    • Science of Emotion and Sensibility
    • /
    • v.18 no.2
    • /
    • pp.45-54
    • /
    • 2015
  • This study carried out an experiment to identify subject's work effectiveness and energy saving effect using LED light. Towards this end, this study configured nine various lighting environments in order to control PWM (Pulse Width Modulation) and illuminance (lux), which are the characteristics of LED light. The PWM ratio of LED light was set as R:G:B=1:1:1, R:G:B=4:1:5, and R:G:B=8:7:7, respectively, and illuminance (lux) was set as 400 lx, 700 lx, and 1000 lx, respectively. In addition, the indoor environment was set temperature $20-24^{\circ}C$, humidity 50%-60%, and the amount of clothing 1. This study analyzed work effectiveness and energy consumption in nine lighting environments, each. Error correction was performed for work effectiveness analysis, and cumulative power consumption was measured in each lighting environment for energy consumption analysis. According to experiment results through the lighting environments suggested in this study, accuracy and spent time effectiveness were good in 700lux and higher than 400lux. For spent time, the best effectiveness was revealed in the suggested PWM ratio, R:G:B=8:7:7. The lowest power consumption on each illuminance (lux) was revealed in the order of R:G:B=8:7:7, RGB=1:1:1, and R:G:B=4:1:5. Therefore, pulse-width modulation effect is proposed in this paper was found to affect the efficiency and energy saving.

Level 3 Type Land Use Land Cover (LULC) Characteristics Based on Phenological Phases of North Korea (생물계절 상 분석을 통한 Level 3 type 북한 토지피복 특성)

  • Yu, Jae-Shim;Park, Chong-Hwa;Lee, Seung-Ho
    • Korean Journal of Remote Sensing
    • /
    • v.27 no.4
    • /
    • pp.457-466
    • /
    • 2011
  • The objectives of this study are to produce level 3 type LULC map and analysis of phenological features of North Korea, ISODATA clustering of the 88scenes of MVC of MODIS NDVI in 2008 and 8scenes in 2009 was carried out. Analysis of phenological phases based mapping method was conducted, In level 2 type map, the confusion matrix was summarized and Kappa coefficient was calculated. Total of 27 typical habitat types that represent the dominant species or vegetation density that cover land surface of North Korea in 2008 were made. The total of 27 classes includes the 17 forest biotopes, 7 different croplands, 2 built up types and one water body. Dormancy phase of winter (${\sigma}^2$ = 0.348) and green up phase in spring (${\sigma}^2$ = 0.347) displays phenological dynamics when much vegetation growth changes take place. Overall accuracy is (851/955) 85.85% and Kappa coefficient is 0.84. Phenological phase based mapping method was possible to minimize classification error when analyzing the inaccessible land of North Korea.

Performance Analysis of Complex Phase-code for Phase Multiplexes Holographic Memory System (위상 다중화 홀로그래픽 메모리 시스템을 위한 CPC 위상코드의 성능 분석)

  • 조병철;김정진;김은수
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.28 no.1C
    • /
    • pp.1-8
    • /
    • 2003
  • In this paper, performance of the CPC(complex phase code) which is recently proposed as a practical phase encoding method for phase-code multiplexes holographic memory system is comparatively analyzed with those of the conventional phase codes such as PR(pure random code), RCE(random code with equality), WHM(Walsh Hadamard Matrix). In computer simulation, the size of an address bean is fixed at 32$\times$32 pixels and 0%-25% phase-error ratio in a pixel are intentionally added to the real phase values to consider the nonlinear phase-modulation characteristics of the practical spatial light modulator. From comparative analysis of crosstalks and signal-to-noise ratios for these phase codes by calculating auto-correlation and cross-correlation, it is found that the CPC have the lowest cross-correlation mean value of 0.021, the lowest standard deviation of 0.0113 and the highest signal-to-noise ratio(SNR) of 27.4 among the four types of phase code. In addition, from the calculation of the number of all possible address beams for these four types of phase code as the size of the address beam is fixed to 3232 pixels, the CPC is found to have 6.334$\times$10$^{49}$ address beams, which are relatively higher number than that of the conventional phase codes.

Statistical Evaluation of Validity of KS Asphalt Penetration Grade System (통계적 분석을 통한 KS 아스팔트 침입도 규격의 문제점 고찰)

  • Kim, Kwang-Woo;Lee, Woo-Hyun;Jung, Jae-Hun;Doh, Young-Soo
    • International Journal of Highway Engineering
    • /
    • v.8 no.4 s.30
    • /
    • pp.125-133
    • /
    • 2006
  • In this study, the Korean Industrial Standard(KS) penetration grade system was examined to evaluate its statistical validity. It was found from this limited study that the system has no gap between each grade, the binder falling out of limit trespasses into other binder grade. Therefore, many products can have similar property level with an adjacent grade even though the mean value is within the specification limit. It was also found out that the equal range setup of each grade, such as 20 for 40-60, 60-80, 80-100, has no statistical foundation. Since KS penetration grade is defined without gap between each grade, the producer must maintain the coefficient of variation below the level by the ASTM system to satisfy the normal quality control limit of products. Due to its lack of a gap between grades, higher percentage of products will be duplicated even if the mean is at the median of the specification limits due to material's quality uncertainty. Especially if the mean moves toward the upper limit, a half or more of the binder grade will be overlapped with the upper binder grade. Therefore, KS penetration specification should be immediately modified by statistically valid methodologies.

  • PDF

Factor Analysis and LISREL Model Development for Landscape Estimation on The Road Cutting Slope Area (도로절토사면(절개면)의 경관평가를 위한 요인분석 및 LISREL 모형구축)

  • 지길용;박일동;임성빈;금기정
    • Journal of Korean Society of Transportation
    • /
    • v.21 no.2
    • /
    • pp.33-43
    • /
    • 2003
  • In South Korea, about 74% of total area is mountainous terrain It is therefore inevitable to make tunnel or cutting slope for road construction. According to a related survey, approximately 2,400 sites of cutting slopes were found from 24 different routes of roadway which is overall 900 km long, implying 2.7 slopes per 1km of roadway on average. Even though safety matter such as the slope failure prevention would be the most important consideration for the construction of cutting slopeslandscape of sloped face is nowadays becoming another important factor due to the growing demand for the driver-friendly road environment Various construction methods which attain this goal should therefore be considered in the design stage of the roadway. The objective of this study is to identify important factors in landscape of sloped-cut roadway using factor analysis. For this, 10 main treatment methods of sloped-cut fact were analyzed. This study employed the LISREL(structural analysis of common variance) model in order to capture the qualitative characteristics of the slope-cut road and examine the relationship between the suey error and the variable(s). As a result, more reasonable landscape evaluation model for the road design and construction was proposed.