• Title/Summary/Keyword: Backward Effect

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The Assessment of Ultraviolet Radiation in Vegetable Growth (식물생장(植物生長)에 미치는 자외선(紫外線)의 효과(效果))

  • Kim, Hyeong-Ok;Moon, Doo-Khil;Lee, Shin-Chan;Kim, Yong-Ho;Song, Pill-Soon
    • Korean Journal of Environmental Agriculture
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    • v.3 no.1
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    • pp.63-70
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    • 1984
  • The terrestrial UV flux rapidly increased in late spring, as measured by the chemical actinometry at two elevations (near sea level and 1,100m above sea level) on Jeju Island. More intense UV fluxes were observed at higher altitudes. Any harmful effects of solar UV-B on the growth of soybean were not detected in UV-B-exclusion experiment. To ascertain the effect of UV radiation on vegetative growth, intact (㏖ wt 124000) and large (${\sim}120000$) phytochromes were irradiated with UV-B radiation. In intact phytochrome, the Pfr form accounts for 60% of the total phytochrome under stationary state conditions, whereas it accounts for 50% in large phytochrome. Calculated quantum yields for the forward and the backward phototransformations of phytochrome by UV were ${\phi}r=0.016$ and ${\phi}fr=0.010$ in intact phytochrome, and ${\phi}r={\phi}fr=0.012$ in large phytochrome, respectively.

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Elementary School Entrance Age and Selection of Gifted Students (출생월에 따른 학교입학연령과 과학영재교육원 영재선발)

  • Lee, Soon-Joo;Park, Chan-Oung
    • Journal of Gifted/Talented Education
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    • v.18 no.2
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    • pp.239-264
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    • 2008
  • The gap in academic achievement owing to entrance age in elementary school has been used as important basic data to formulate policies on school entrance system and other educational policies. Other countries have made further studies to prove the effect on academic achievement of age gap between students in the same grade. This study identified the clear difference in a component ratio in the participants and the successful candidates based on the by entrance age during the entrance examination of the "K" science education center for the gifted. Also, this study analyzed the difference in success in an examination depending on the season of birth between the participants and the successful candidates during the entrance examination. It also compared the birth ratio by season of each group including common students. Some preceding studies with common or backward students show the result that students who entered the school in full age have higher level of academic achievements than students in younger age. But the results of this study proved that gifted students who entered the school in full age did not have a high level of academic achievements. Like these studies, this study show the result that school entrance age works as an important factor of selection of gifted students. Students who entered the school in full age entered much more the "K" science education center for gifted students than students in young age.

Neuropsychological Approaches to Mathematical Learning Disabilities and Research on the Development of Diagnostic Test (신경심리학적 이론에 근거한 수학학습장애의 유형분류 및 심층진단검사의 개발을 위한 기초연구)

  • Kim, Yon-Mi
    • Education of Primary School Mathematics
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    • v.14 no.3
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    • pp.237-259
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    • 2011
  • Mathematics learning disabilities is a specific learning disorder affecting the normal acquisition of arithmetic and spatial skills. Reported prevalence rates range from 5 to 10 percent and show high rates of comorbid disabilities, such as dyslexia and ADHD. In this study, the characteristics and the causes of this disorder has been examined. The core cause of mathematics learning disabilities is not clear yet: it can come from general cognitive problems, or disorder of innate intuitive number module could be the cause. Recently, researchers try to subdivide mathematics learning disabilities as (1) semantic/memory type, (2) procedural/skill type, (3) visuospatial type, and (4) reasoning type. Each subtype is related to specific brain areas subserving mathematical cognition. Based on these findings, the author has performed a basic research to develop grade specific diagnostic tests: number processing test and math word problems for lower grades and comprehensive math knowledge tests for the upper grades. The results should help teachers to find out prior knowledge, specific weaknesses of students, and plan personalized intervention program. The author suggest diagnostic tests are organized into 6 components. They are number sense, conceptual knowledge, arithmetic facts retrieval, procedural skills, mathematical reasoning/word problem solving, and visuospatial perception tests. This grouping will also help the examiner to figure out the processing time for each component.

The Effects of Wearing Roller Shoes on Ground Reaction Force Characteristics During Walking (롤러 신발과 조깅 슈즈 신발 착용 후 보행 시 지면반력의 형태 비교 분석)

  • Chae, Woen-Sik
    • Korean Journal of Applied Biomechanics
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    • v.16 no.1
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    • pp.101-108
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    • 2006
  • The purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes. Twelve male middle school students (age: $15.0{\pm}0.0\;yrs$, height: $173.6{\pm}5.0\;cm$, weight: $587.6{\pm}89.3\;N$) who have no known musculoskeletal disorders were recruited as the subjects. Kinematic data from six S-VHS camcorders(Panasonic AG456, 60 fields/s) and GRF data from two force platform; (AMII OR6-5) were collected while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and GRF recordings. GRF data were filtered using a 20 Hz low pass Butterworth. digital filter and further normalized to the subject's body weight. For each trial being analyzed, five critical instants and four phases were identified from the recording. Temporal parameters, GRFs, displacement of center of pressure (DCP), and loading and decay rates were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p <.05). Vertical GRFs at heel contact increased and braking forces at the end of initial double limb stance reduced significantly when going from jogging shoe to roller shoe condition. Robbins and Waked (1997) reported that balance and vertical GRF are closely related It seems that the ankle and knee joints are locked in an awkward fashion at the heel contact to compensate for the imbalance. The DCP in the antero-posterior direction for the roller shoe condition was significantly less than the corresponding value for the jogging shoe condition. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the DCP for the roller shoe condition was restricted The results indicate that walking with roller shoes had little effect on temporal parameters, and loading and decay rates. It seems that there are differences in GRF characteristics between roller shoe and jogging shoe conditions. The differences in GRF pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine muscle activation patterns and joint kinematics during walking with roller shoes.

A study on treatment effects of Class III cases by second molar extraction (제 2 대구치 발거에 의한 III급 부정교합자의 치료효과에 관한 연구)

  • Lee, Sung-Hee;Park, Young-Guk;Chung, Kyu-Rhim
    • The korean journal of orthodontics
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    • v.34 no.2 s.103
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    • pp.109-119
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    • 2004
  • This study aimed at investigating the skeletal, dentoalveolar, and soft tissue changes of Class III malocclusion cases treated by second molar extraction. The lateral cephalograms of 15 subjects with moderate Class III malocclusion by average ANB $-1.4^{\circ}\;and\;IMPA\;85^{\circ}$ were traced and the computerized superimposition of average craniofacial change was made. The data was gathered and statistically analyzed. The results were as follows: 1 Lower anterior facial height/anterior facial height increased by 0.6%(P<0.01), mandibular plane increased by $1.5^{\circ}$(P<0.05). 2. There was a slightly downward & backward rotation of the mandible. 3. Lower first molar tipped distally by 4.nm(P<0.001), lower anterior teeth lingually tipped by $3.2^{\circ}$(P<0.05). 4. Retracted lower lip improved facial profile. This study may suggest that second molar extraction could be effective for a moderate Class III malocclusion to make distalization of the lower first molar easier and avoid severe lingual tipping of the lower incisor, if the lower third molar has a normal shape, good direction of eruption and adequate time for lower second molar extraction

The effect of treatment timing on maxillary protraction treatment response - A comparison of prepubertal and pubertal patients (치료시기에 따른 상악골 전방견인효과 - 사춘기전과 사춘기의 비교)

  • Kim, Kyung-Ho;Choy, Kwang-Chul;Baik, Hyoung-Seon;Lee, Ji-Hyun
    • The korean journal of orthodontics
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    • v.32 no.5 s.94
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    • pp.301-312
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    • 2002
  • Treatment timing is a very important factor to consider in treating skeletal Class III patients by means of maxillary protraction. According to the literature maxillary Protraction should be carried out at an early age before puberty. However, no scientific data were presented to support this statement and recent studies supported by statistical data showed disagreement concerning the optimum treatment time of maxillary protraction. Therefore, there is no agreement about the optimum treatment time of maxillary protraction. In this study hand-wrist X-rays were taken from 119 patients and subjects were grouped into prepubertal and pubertal group according to their skeletal maturity. Pretreatment and posttreatment lateral cephalometric X-rays were taken and treatment effects were compared. The average treatment time was 6.5 months for the prepubertal group and 6.1 months for the pubertal group. The obtained results were as follows ; 1. The amount of maxillary forward movement was the same for Pretreatment and pubertal group. 2. The amount of maxillary downward movement was the same for prepubertal and pubertal group. 3. The amount of mandibular downward and backward rotational movement was the same for prepubertal and pubertal group. 4. Dental effects were the same for prepubertal and pubertal group.

Effects of Large Display Curvature on Postural Control During Car Racing Computer Game Play (자동차 경주 컴퓨터 게임 시 대형 디스플레이 곡률이 자세 제어에 미치는 영향)

  • Yi, Jihhyeon;Park, Sungryul;Choi, Donghee;Kyung, Gyouhyung
    • Journal of the HCI Society of Korea
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    • v.10 no.2
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    • pp.13-19
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    • 2015
  • Display technology has recently made enormous progress. In particular, display companies are competing each other to develop flexible display. Curved display, as a precursor of flexible display, are now used for smart phones and TVs. Curved monitors have been just introduced in the market, and are used for office work or entertainment. The aim of the current study was to investigate whether the curvature of a 42" multi-monitor affects postural control when it is used for entertainment purpose. The current study used two curvature levels (flat and 600mm). Ten college students [mean(SD) age = 20.9 (1.5)] with at least 20/25 visual acuity, and without color blindness and musculoskeletal disorders participated in this study. In a typical VDT environment, each participant played a car racing video game using a steering wheel and pedals for 30 minutes at each curvature level. During the video game, a pressure mat on the seat pan measured the participant's COP (Center of Pressure), and from which four measures (Mean Velocity, Median Power Frequency, Root-Mean-Square Distance, and 95% Confidence Ellipse Area) were derived. A larger AP (Anterior-Posterior) RMS distance was observed in the flat condition, indicating more forward-backward upper body movements. It can be partly due to more variability in visual distance across display, and hence longer ocular accommodation time in the case of the flat display. In addition, a different level of presence or attention between two curvature conditions can lead to such a difference. Any potential effect of such a behavioral change by display curvature on musculoskeletal disorders should be further investigated.

Effect of Immediate Dynamic Balance Ability of Chronic Low Back Pain on Maitland's Manual Therapy (메이트란드 도수치료가 만성 요통환자의 즉각적인 동적 균형능력에 미치는 영향)

  • Hyong, In-Hyouk;Ha, Mi-Sook
    • The Journal of the Korea Contents Association
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    • v.9 no.6
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    • pp.207-215
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    • 2009
  • There has been a diversity of therapeutic interventions for patients with chronic low back pain. However most of them have been focused on only pain. But the patients usually have a kind of structurally abnormal have fixed in lumbar vertebrae, which can decrease range of joint movement and, what is worse, reduce immediate dynamic balancing ability(IDBA). The reduced IDBA can increase the risk of injury and decrease coping ability in dangerous situation. So we introduced Maitland's manual therapy in this study in order to recover the IDBA in patients with chronic low back pain. Sixty-four patients diagnosed with chronic low back pain were included for the study. Among them, thirty-two patients(experimental group) were managed by Maitland's manual therapy, another thirty-tow patients(control group) were treated by physical science methods(H/P, TENS, U/S). Each group made use of highly reliable(0.81$\sim$0.96) star excursion balance test(SEBT) to compare the possible changes of IDBAs in two groups after treatment. In experimental group, IDBA has increased in forward, rightward, leftward, and backward, but in control group, not changed. According to the results, we concluded that Maitland's manual therapy is effective for increasing IDBA by making joints more flexible in lumbar vertebrae.

Implicit Numerical Integration of Two-surface Plasticity Model for Coarse-grained Soils (Implicit 수치적분 방법을 이용한 조립토에 관한 구성방정식의 수행)

  • Choi, Chang-Ho
    • Journal of the Korean Geotechnical Society
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    • v.22 no.9
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    • pp.45-59
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    • 2006
  • The successful performance of any numerical geotechnical simulation depends on the accuracy and efficiency of the numerical implementation of constitutive model used to simulate the stress-strain (constitutive) response of the soil. The corner stone of the numerical implementation of constitutive models is the numerical integration of the incremental form of soil-plasticity constitutive equations over a discrete sequence of time steps. In this paper a well known two-surface soil plasticity model is implemented using a generalized implicit return mapping algorithm to arbitrary convex yield surfaces referred to as the Closest-Point-Projection method (CPPM). The two-surface model describes the nonlinear behavior of coarse-grained materials by incorporating a bounding surface concept together with isotropic and kinematic hardening as well as fabric formulation to account for the effect of fabric formation on the unloading response. In the course of investigating the performance of the CPPM integration method, it is proven that the algorithm is an accurate, robust, and efficient integration technique useful in finite element contexts. It is also shown that the algorithm produces a consistent tangent operator $\frac{d\sigma}{d\varepsilon}$ during the iterative process with quadratic convergence rate of the global iteration process.

Self-optimizing feature selection algorithm for enhancing campaign effectiveness (캠페인 효과 제고를 위한 자기 최적화 변수 선택 알고리즘)

  • Seo, Jeoung-soo;Ahn, Hyunchul
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.173-198
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    • 2020
  • For a long time, many studies have been conducted on predicting the success of campaigns for customers in academia, and prediction models applying various techniques are still being studied. Recently, as campaign channels have been expanded in various ways due to the rapid revitalization of online, various types of campaigns are being carried out by companies at a level that cannot be compared to the past. However, customers tend to perceive it as spam as the fatigue of campaigns due to duplicate exposure increases. Also, from a corporate standpoint, there is a problem that the effectiveness of the campaign itself is decreasing, such as increasing the cost of investing in the campaign, which leads to the low actual campaign success rate. Accordingly, various studies are ongoing to improve the effectiveness of the campaign in practice. This campaign system has the ultimate purpose to increase the success rate of various campaigns by collecting and analyzing various data related to customers and using them for campaigns. In particular, recent attempts to make various predictions related to the response of campaigns using machine learning have been made. It is very important to select appropriate features due to the various features of campaign data. If all of the input data are used in the process of classifying a large amount of data, it takes a lot of learning time as the classification class expands, so the minimum input data set must be extracted and used from the entire data. In addition, when a trained model is generated by using too many features, prediction accuracy may be degraded due to overfitting or correlation between features. Therefore, in order to improve accuracy, a feature selection technique that removes features close to noise should be applied, and feature selection is a necessary process in order to analyze a high-dimensional data set. Among the greedy algorithms, SFS (Sequential Forward Selection), SBS (Sequential Backward Selection), SFFS (Sequential Floating Forward Selection), etc. are widely used as traditional feature selection techniques. It is also true that if there are many risks and many features, there is a limitation in that the performance for classification prediction is poor and it takes a lot of learning time. Therefore, in this study, we propose an improved feature selection algorithm to enhance the effectiveness of the existing campaign. The purpose of this study is to improve the existing SFFS sequential method in the process of searching for feature subsets that are the basis for improving machine learning model performance using statistical characteristics of the data to be processed in the campaign system. Through this, features that have a lot of influence on performance are first derived, features that have a negative effect are removed, and then the sequential method is applied to increase the efficiency for search performance and to apply an improved algorithm to enable generalized prediction. Through this, it was confirmed that the proposed model showed better search and prediction performance than the traditional greed algorithm. Compared with the original data set, greed algorithm, genetic algorithm (GA), and recursive feature elimination (RFE), the campaign success prediction was higher. In addition, when performing campaign success prediction, the improved feature selection algorithm was found to be helpful in analyzing and interpreting the prediction results by providing the importance of the derived features. This is important features such as age, customer rating, and sales, which were previously known statistically. Unlike the previous campaign planners, features such as the combined product name, average 3-month data consumption rate, and the last 3-month wireless data usage were unexpectedly selected as important features for the campaign response, which they rarely used to select campaign targets. It was confirmed that base attributes can also be very important features depending on the type of campaign. Through this, it is possible to analyze and understand the important characteristics of each campaign type.