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Analysis of Spatial Variability in a Korean Paddy Field Using Median Polish Detrending (Median polish 기법을 이용한 한국 논의 공간변이 분석)

  • Chung, Sun-Ok;Jung, In-Kyu;Sung, Je-Hoon;Sudduth, Kenneth A.;Drummond, Scott T.
    • Journal of Biosystems Engineering
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    • v.33 no.5
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    • pp.362-369
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    • 2008
  • There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

Autonomous Mobile Robot System Using Adaptive Spatial Coordinates Detection Scheme based on Stereo Camera (스테레오 카메라 기반의 적응적인 공간좌표 검출 기법을 이용한 자율 이동로봇 시스템)

  • Ko Jung-Hwan;Kim Sung-Il;Kim Eun-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.1C
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    • pp.26-35
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    • 2006
  • In this paper, an automatic mobile robot system for a intelligent path planning using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth information can be detected. Finally, based-on the analysis of these calculated coordinates, a mobile robot system is derived as a intelligent path planning and a estimation. From some experiments on robot driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the distance between the mobile robot and the objects, and relative distance between the other objects is found to be very low value of 2.19% and 1.52% on average, respectably.

Effect of Taklisodok-um and Hwangryunhaedok-tang on Atopic Dermatitis (탁리소독음(托裏消毒飮) 합(合) 황련해독탕(黃連解毒湯)의 아토피피부염에 대한 실험적 연구)

  • Weon, Young-Ho;Hwang, Chung-Yeon;Lim, Kyu-Sang;Kim, Jong-Han;Ko, Seong-Gyu;Lee, Boo-Kyun;Lee, Dong-Hyo;Kim, Nam-Kwen
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.24 no.1
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    • pp.121-141
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    • 2011
  • Objective : This Experimental study was done to investigate the Effect of Taklisodok-um and Hwangryunhaedok-tang(TH) on Atopic Dermatitis. Methods : We assessed effects of TH on the IgE, IL-4, IL-5, IL-6, IgM, IgG1, IFN-γ in vivo, on the IL-4, IL-5, CCR3 in the skin tissues of ear and dorsum with NC/Nga mice. And we assessed effects of TH on the COX-2, IL-1β, TNF-α, IL-6 with RAW 264.7 cell. Results and Conclusion : 1. IgE, IL-4, IL-5, IL-6, IgM, IgGl levels in the serum of TH treated NC/Nga mouse group were decreased compared to the untreated control mice. IFN-r showed a increase in the experimental group compared to the untreated control group. The spleen weight of TH treated NC/Nga mice was decreased compared to the untreated control group. 2. mRNA expression levels of IL-4, IL-5 and CCR3 in the skin tissues of TH treated NC/Nga mice were decreased, and expression levels of IL-6 in the skin tissues of TH treated NC/Nga mice were decreased compared to the untreated control group. IFN-γ mRNA expression levels were increased compared to the untreated control group. 3. Judged from that IL-1β, TNF-α, IL-6 express of gene, effect of inflammatory Cytokines revelation were decreased compared to the untreated control group. 4. Depend on the strength of TH, inflammatory RAW 264.7 in the serum of TH were inhibited compared to the untreated control serum that leaded a COX-2 activity model. 5. Histological observation of the ear and skin tissues showed that the extents of inflammation and infiltrated immune cells in the epidermis and dermis of TH treated NC/Nga mice were highly reduced compared to the untreated control group.

Rotordynamic Analysis of a Dual-Spool Turbofan Engine with Focus on Blade Defect Events (블레이드 손상에 따른 이축식 터보팬 엔진의 동적 안정성 해석)

  • Kim, Sitae;Jung, Kihyun;Lee, Junho;Park, Kihyun;Yang, Kwangjin
    • Tribology and Lubricants
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    • v.36 no.2
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    • pp.105-115
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    • 2020
  • This paper presents a numerical study on the rotordynamic analysis of a dual-spool turbofan engine in the context of blade defect events. The blades of an axial-type aeroengine are typically well aligned during the compressor and turbine stages. However, they are sometimes exposed to damage, partially or entirely, for several operational reasons, such as cracks due to foreign objects, burns from the combustion gas, and corrosion due to oxygen in the air. Herein, we designed a dual-spool rotor using the commercial 3D modeling software CATIA to simulate blade defects in the turbofan engine. We utilized the rotordynamic parameters to create two finite element Euler-Bernoulli beam models connected by means of an inter-rotor bearing. We then applied the unbalanced forces induced by the mass eccentricities of the blades to the following selected scenarios: 1) fully balanced, 2) crack in the low-pressure compressor (LPC) and high pressure compressor (HPC), 3) burn on the high-pressure turbine (HPT) and low pressure compressor, 4) corrosion of the LPC, and 5) corrosion of the HPC. Additionally, we obtained the transient and steady-state responses of the overall rotor nodes using the Runge-Kutta numerical integration method, and employed model reduction techniques such as component mode synthesis to enhance the computational efficiency of the process. The simulation results indicate that the high-vibration status of the rotor commences beyond 10,000 rpm, which is identified as the first critical speed of the lower speed rotor. Moreover, we monitored the unbalanced stages near the inter-rotor bearing, which prominently influences the overall rotordynamic status, and the corrosion of the HPC to prevent further instability. The high-speed range operation (>13,000 rpm) coupled with HPC/HPT blade defects possibly presents a rotor-case contact problem that can lead to catastrophic failure.

An investigative study of enrichment reduction impact on the neutron flux in the in-core flux-trap facility of MTR research reactors

  • Xoubi, Ned;Darda, Sharif Abu;Soliman, Abdelfattah Y.;Abulfaraj, Tareq
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.469-476
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    • 2020
  • Research reactors in-core experimental facilities are designed to provide the highest steady state flux for user's irradiation requirements. However, fuel conversion from highly enriched uranium (HEU) to low enriched uranium (LEU) driven by the ongoing effort to diminish proliferation risk, will impact reactor physics parameters. Preserving the reactor capability to produce the needed flux to perform its intended research functions, determines the conversion feasibility. This study investigates the neutron flux in the central experimental facility of two material test reactors (MTR), the IAEA generic10 MW benchmark reactor and the 22 MW s Egyptian Test and Research Reactor (ETRR-2). A 3D full core model with three uranium enrichment of 93%, 45%, and 20% was constructed utilizing the OpenMC particle transport Monte Carlo code. Neutronics calculations were performed for fresh fuel, the beginning of life cycle (BOL) and end of life cycle (EOL) for each of the three enrichments for both the IAEA 10 MW generic reactor and core 1/98 of the ETRR-2 reactor. Criticality calculations of the effective multiplication factor (Keff) were executed for each of the twelve cases; results show a reasonable agreement with published benchmark values for both reactors. The thermal, epithermal and fast neutron fluxes were tallied across the core, utilizing the mesh tally capability of the code and are presented here. The axial flux in the central experimental facility was tallied at 1 cm intervals, for each of the cases; results for IAEA 10 MW show a maximum reduction of 14.32% in the thermal flux of LEU to that of the HEU, at EOL. The reduction of the thermal flux for fresh fuel was between 5.81% and 9.62%, with an average drop of 8.1%. At the BOL the thermal flux showed a larger reduction range of 6.92%-13.58% with an average drop of 10.73%. Furthermore, the fission reaction rate was calculated, results showed an increase in the peak fission rate of the LEU case compared to the HEU case. Results for the ETRR-2 reactor show an average increase of 62.31% in the thermal flux of LEU to that of the HEU due to the effect of spectrum hardening. The fission rate density increased with enrichment, resulting in 34% maximum increase in the HEU case compared to the LEU case at the assemblies surrounding the flux trap.

Effect of Temperature on the Development of Bracon hebetor (Hymenoptera: Braconidae) Parasitizing Indianmeal Moth (Lepidoptera: Pyralidae) (화랑곡나방(나비목: 명나방과)에 기생한 보리나방살이고치벌 (벌목: 고치벌과)의 발육과 온도와의 관계)

  • 김나경;나자현;류문일
    • Korean journal of applied entomology
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    • v.39 no.4
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    • pp.275-279
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    • 2000
  • Development of Bracon hebetor Say parasitizing Indianmeal moth (Plodia interpunctella (Hubner) was studied at five temperature conditions (17, 20, 25, 28 and 32±0.5C) under a photoperiod of 16 : 8 (L : D). Developmental period (mean±s.e.) of B. hebetor from egg to eclosion decreased from 28.6±0.50 to 9.3 ±0.09 days and 28.1 ±0.51 to 9.2±0.09 days for female and male, respectively, as the temperature increased from 17 to 32C. The combination model provided a good description of the relationship between temperature and development. The low temperature thresholds were estimated to be 14.0, 12.8, 15.1C for development of egg, larva and pupa. The thresholds for normal development (outside of the boundary layer of the development) were 14.0, 17.5, 15.1C for egg, larva and pupa, respectively, indicating that the larval stage is more sensitive to the low temperature than the other stages. The results suggested that the present B. hebetor population could be another ecological race adapting to the seasonal temperature conditions of this area.

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Production of Rhizobium meliloti M14 Inoculum by Semi-continuous Cultivation (반연속식(半連續式) 배양(培養)에 의(依)한 Rhizobium meliloti M14의 균체생산(菌體生産))

  • Choi, Woo Young;Sohn, Jong Rok;Kim, Moon Kyu
    • Korean Journal of Agricultural Science
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    • v.11 no.2
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    • pp.322-327
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    • 1984
  • As a basic studies for the laboratory scale production of alfalfa inoculum, Rhizobium meliloti M14 was characterized for its carbon and nitrogen sources, and some parameters for broth cultivation in a chemostat were studied by semi-continuous operation. The result s obtained were as follows. 1. Growth rate of the strain was increased by disaccharides than by monosaccharides tested, and pentoses resulted in poor growth than hexoses. Sugar alcohols including inositol supported the best growth among sugars. 2. Mannitol in the yeast-mannitol-broth was substituted by natural carbon sources such as malt extract or molasses. 3. Ten per cent of fresh yeast water appeared to supply enough amount of growth factor s for the strain, and the effect was equivalent to 0.24 percent of the commercial yeast extract powder. 4. Batch growth of the stain in a chemostat, New Brunswick Micro Ferm 28L, reached in the early stationary growth phase of 57×109cells/ml after 36 hours of incubation. The culture at this stage was switched to semi-continuous cultivation, and the culture broth of four-fifth of the working volume was recovered every 24 hours when the maximal count was obtained.

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Relations between class distracting factors and class satisfaction of dental technology students (치기공과 학생의 수업 방해 요인과 수업 만족도와의 관계)

  • Kwon, Soon-Suk;Lee, Hye-Eun
    • Journal of Technologic Dentistry
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    • v.39 no.4
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    • pp.263-273
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    • 2017
  • Purpose: This study aimed to explore the relations between class distracting factors and class satisfaction of the dental technology students and then provide a primary data to help further related studies and develop educational programs with which instructors can efficiently manage their classroom. Methods: For this study we have conducted a survey started from the beginning of May 2017 to the end of June. The subjects of the survey were Dental Technology students of D-city, K-city, W-city, selected by random sampling method. The questionnaire was self-administrated and 437 valid results were chosen for our analysis among 450 distributed questionnaires. Results: The results of the research was as follows. Firstly, The overall average point of class distracting factors was 2.5 point. The environmental factors were the highest point as 2.59 and as for the subcategories tiredness and drowsiness was the highest point as 2.76. Secondly, The overall average point of class satisfaction turned out 3,88 point and compliance with class and attitude factors gained the highest point as 4.06. Of the subcategories strict roll checking was the highest point as 4.17. Thirdly, As for class distracting factors from general characteristics a statistical significance was shown as follows; 'instructor factor'(p<.01), 'learner factor'(p<.05), 'total class distracting factor'(p<.05) in the area of gender, 'environmental factor'(p<.001), 'total class distracting factor'(p<.01), 'learner factor'(p<.05), 'instructor factor'(p<.05) in the area of gender 'learner factor'(p<.001), 'instructor factor'(p<.001), 'environmental factor'(p<.001), 'total class distracting factor'(p<.01) in the area of class grade, 'environmental factor'(p<.05) in GPA. Fourthly, A statistical significance, a negative correlation (p<.01) were shown between class distracting factors and class satisfaction. Class distracting factor that especially affects the class satisfaction was instructor factor(p<.001) and the explanatory power of the model turned out 14.7%, which was statistically meaningful (p<.001). Conclusion : Results of this study reveal that instructor factor is the key to class satisfaction of the students. So it is crucial that the instructor faithfully prepare for the class to reinforce the students' learning. Additionally further studies should be followed with more subjects and newer perspectives to develop innovative teaching methodology.

Two-Stage Evolutionary Algorithm for Path-Controllable Virtual Creatures (경로 제어가 가능한 가상생명체를 위한 2단계 진화 알고리즘)

  • Shim Yoon-Sik;Kim Chang-Hun
    • Journal of KIISE:Computer Systems and Theory
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    • v.32 no.11_12
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    • pp.682-691
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    • 2005
  • We present a two-step evolution system that produces controllable virtual creatures in physically simulated 3D environment. Previous evolutionary methods for virtual creatures did not allow any user intervention during evolution process, because they generated a creature's shape, locomotion, and high-level behaviors such as target-following and obstacle avoidance simultaneously by one-time evolution process. In this work, we divide a single system into manageable two sub-systems, and this more likely allowsuser interaction. In the first stage, a body structure and low-level motor controllers of a creature for straight movement are generated by an evolutionary algorithm. Next, a high-level control to follow a given path is achieved by a neural network. The connection weights of the neural network are optimized by a genetic algorithm. The evolved controller could follow any given path fairly well. Moreover, users can choose or abort creatures according to their taste before the entire evolution process is finished. This paper also presents a new sinusoidal controller and a simplified hydrodynamics model for a capped-cylinder, which is the basic body primitive of a creature.

A Probabilistic Assessment of Human Health Risk from Arsenic-Contaminated Rice Grown Near The Mining Areas of Korea

  • Paik, Min-Kyoung;Kim, Won-Il;Yoo, Ji-Hyock;Kim, Jin-Kyoung;Im, Geon-Jae;Hong, Moo-Ki
    • Journal of Food Hygiene and Safety
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    • v.25 no.2
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    • pp.143-147
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    • 2010
  • Chronic exposure to Arsenic (As) causes significant human health effects including various cancers. Total As concentrations from 300 polished rice samples cultivated near the mining areas in Korea were analyzed to estimate a probabilistic assessment of human health risk from As-contaminated rice. The mean of total As concentrations in rice was 0.09 mg/kg and lognormal distribution model was set for total As concentrations. Human health risk for As in rice was estimated using gender-specific rice consumption data and average daily dose (ADD). While cancer risk (CR) and hazard quotient (HQ) were calculated using oral cancer slope factor (OCSF) and Reference dose (RfD) suggested by the U.S. EPA. Mean of CR posed by total As was 2.16 (for male) and 1.83 (for female) per 10,000. The HQ for general population from rice cultivated near the mining areas in Korea was below 1 as the 50th percentile of general population. However, less than 10% of general population consuming rice cultivated near the mining areas would exceed 1.0. This result is similar with those from each gender-specific group.