• 제목/요약/키워드: Variable block

검색결과 414건 처리시간 0.023초

동시과제가 운전 수행 능력에 미치는 영향 -차량 통제 및 동작신호 해석을 중심으로- (Effects of Secondary Task on Driving Performance -Control of Vehicle and Analysis of Motion signal-)

  • 문경률;최진승;강동원;방윤환;김한수;이수정;양재웅;김지혜;최미현;지두환;민병찬;정순철;탁계래
    • 감성과학
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    • 제13권4호
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    • pp.613-620
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    • 2010
  • 본 연구의 목적은 차량 통제 변인과 동작의 부드러움 변인을 이용하여 동시 과제 수행이 운전 수행 능력에 미치는 영향을 정량적으로 제시하는 것이다. 1~2년의 운전 경력을 가진 피험자 20명이 실험에 참여하였다. 피험자는 동작분석을 위해 상지(shoulder, elbow, wrist) 및 하지(knee, ankle, toe)에 9개의 마커를 부착한 후, 운전 시뮬레이터를 이용하여 80km/hr로 주행하는 선행 차량과 30m의 간격을 유지하며 직선 주행하도록 하였다. 동시과제는 문자 메시지 보내기와 네비게이션 검색으로 선정하였다. 실험 시간은 2분으로 운전 시작 후 1분은 운전만을, 다음 1분은 운전과 동시과제를 함께 실시하도록 하였고, 각각 운전구간과 동시과제구간으로 정의하였다. 차간거리(Anterior-Posterior Coefficient of Variation, APCV) 및 차선이격거리의 분산계수(Medial-Lateral Coefficient of variation, MLCV)와 저크비용함수(Jerk-cost function, JC)를 이용하여 운전 수행 능력을 평가하였다. APCV는 운전구간에 비해 운전 중 네비게이션 검색 시 222.1% 증가하였다. MLCV는 문자 메시지 전송 과제를 수행할 경우, 318.2%, 네비게이션 검색 과제를 수행할 경우 309.4%가 증가하였다. JC는 운전구간에 비해 동시과제 수행 시, 팔꿈치, 무릎, 발목, 발가락에서 유의하게 증가하였고, 하지마커 전체의 평균값은 문자과제 수행 시 218.2%, 네비게이션 과제 수행 시 294.7%가 증가하였다. 운전 중 동시과제의 수행은 JC를 증가시켜 운전자의 동작의 부드러움을 감소시키고, APCV와 MLCV를 증가시켜 차량의 횡적 종적 통제를 어렵게 한다고 결론 내릴 수 있다.

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액상분뇨의 종류 및 N 시용량이 연맥의 무기물 함량, 질산태질소 및 토양특성에 미치는 영향 (Mineral Content and Nitrate-N of Oats, and Soil Characteristics as Affected by Different Types and N Rates of Liquid Manure)

  • 신동은;김동암;서성;이종경;정의수;신재순;김원호
    • 한국초지조사료학회지
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    • 제19권3호
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    • pp.203-210
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    • 1999
  • 가축액비의 영양성분 중 질소(N)는 환경적인 면과 사초수량을 고려했을 때 잠재력이 가장 높다. 본 연구는 추파용 연맥에 가축액비의 N 함량을 기준으로 시용수준을 달리하여 시용했을 때 추파용 연맥(Avena saliva L.)의 무기물 함량 및 질산태질소 함량 그리고 토양화학성분 변화를 구명하고자 7처리(화학비료표준구 $120kg\;N\;ha^{-1}$, 우분액비구 120, 240, $360kg\;N\;ha^{-1}$ 돈분액비구 120, 240, $360kg\;N\;ha^{-1}$)를 난괴법 3반복으로 배치하여 1997년 수원에서 수행하였다. 대조구와 비교하여 추파용 연맥의 무기물 함량은 액상분뇨의 시용량이 증가됨에 따라 증가되는 경향을 보였다. 추파용 연맥의 질산태질소 함량은 $1,881-2,605mg\;kg^{-1}$의 범위를 보였으며, 금비구>우분액비 $360kg\;N\;ha^{-1}$구>돈분액비 $240kg\;N\;ha^{-1}$구 순이었다. 액상분뇨의 시용량이 증가될 수록 토양중 치환성 양이온 함량이 높아지는 경향을 보였다. 토양중 전질소 및 무기태질소량은 액상분뇨 시용량에 따라 달랐는데 그 중에서도 돈분액비 $360kg\;N\;ha^{-1}$ 구에서 가장 높았다. 토양침투수중 질산태질소 농도는 시험기간중 심한 변이를 나타내지 않았다. 이상의 결과로 볼 때 토양중 질소량은 돈분액비 $360kg\;N\;ha^{-1}$구, 돈분액비 $240kg\;N\;ha^{-1}$ 순이었다.

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지르코니아/알루미나 복합 지대주의 생물학적 안정성에 관한 연구 (Biological stability of Zirconia/Alumina composite ceramic Implant abutment)

  • 배규현;한증석;김태일;설양조;이용무;구영;조기영;정종평;한수부;류인철
    • Journal of Periodontal and Implant Science
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    • 제36권2호
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    • pp.555-565
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    • 2006
  • The purpose of the present study is to evaluate the biological stability of the zirconia/alumina composite abutment by histologic and radiographic examination in clinical cases. 17 partially edentulous patients (5 men and 12 women, mean age 47) were treated with 37 implants. The implants were placed following the standard two-stage protocol. After a healing period of 3 to 6 months, zirconia/alumina composite abutments were connected. All radiographs were taken using paralleling technique with individually fabricated impression bite block, following insertion of the prosthesis and at the 3-, 6-, 12 month re-examinations. After processing the obtained images, the osseous level was calculated using the digital image in the mesial and distal aspect in each implant. An ANOVA and t-test were used to test for difference between the baseline and 3-, 6-, 12 months re-examinations, and for difference between maxilla and mandible. Differences at P <0.05 were considered statistically significant. For histologic examination, sample was obtained from the palatal gingiva which implant functioned for 12 months. Sections were examined under a light microscope under various magnifications. Clinically, no abutment fracture or crack as well as periimplantitis was observed during the period of study. The mean bone level reduction(${\pm}standard$ deviation) was 0.34 rom(${\pm}\;0.26$) at 3-months, 0.4 2mm(${\pm}\;0.30$) at 6-months, 0.62 mm(${\pm}\;0.28$) at 12-months respectively. No statistically significant difference was found between baseline and 3-, 6-, 12-months re-examinations (p > 0.05). The mean bone level reduction in maxilla was 0.33(${\pm}0.25$) at 3-months, 0.36(${\pm}0.33$) at 6-months, 0.56(${\pm}0.26$) at 12-months. And the mean bone level reduction in mandible was 0.35(${\pm}0.27$) at 3-months, 0,49(${\pm}0.27$) at 6-months, 0.68(${\pm}0.30$) at 12-months. No statistical difference in bone level reduction between implants placed in the maxilla and mandible. Histologically, the height of the junctional epithelium was about 2.09 mm. And the width was about 0.51 mm. Scattered fibroblasts and inflammatory cells, and dense collagen network with few vascular structures characterized the portion of connective tissue. The inflammatory cell infiltration was observed just beneath the apical end of junctional epithelium and the area of direct in contact with zirconia/alumina abutment. These results suggest the zirconia/alumina composite abutment can be used in variable intraoral condition, in posterior segment as well as anterior segment without adverse effects.

크리핑 벤트그라스 훼어웨이에서 관수회수.예지물과 질소시비수준이 엽조직 및 토양 질소함유량에 미치는 효과 (A Three-year Study on the Leaf and Soil Nitrogen Contents Influenced by Irrigation Frequency, Clipping Return or Removal and Nitrogen Rate in a Creeping Bentgrass Fairway)

  • 김경남;로버트쉬어만
    • 아시안잔디학회지
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    • 제11권2호
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    • pp.105-115
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    • 1997
  • Responses of 'Penncross' creeping bentgrass turf to various fairway cultural practices are not well-established or supported by research results. This study was initiated to evaluate the effects of irrigation frequency, clipping return or removal, and nitrogen rate on leaf and soil nitrogen con-tent in the 'Penncross' creeping bentgrass (Agrostis palustris Huds.) turf. A 'Penncross' creeping bentgrass turf was established in 1988 on a Sharpsburg silty-clay loam (Typic Argiudoll). The experiment was conducted from 1989 to 1991 under nontraffic conditions. A split-split-plot experimental design was used. Daily or biweekly irrigation, clipping return or removal, and 5, 15, or 25 g N $m-^2$ $yr-^1$ were the main-, sub-, and sub-sub-plot treatments, respectively. Treatments were replicated 3 times in a randomized complete block design. The turf was mowed 4 times weekly at a l3 mm height of cut. Leaf tissue nitrogen content was analyzed twice in 1989 and three times in both 1990 and 1991. Leaf samples were collected from turfgrass plants in the treatment plots, dried immediately at 70˚C for 48 hours, and evaluated for total-N content, using the Kjeldahl method. Concurrently, six soil cores (18mm diam. by 200 mm depth) were collected, air dried, and analyzed for total-N content. Nitrogen analysis on the soil and leaf samples were made in the Soil and Plant Analyical Laboratory, at the University of Nebraska, Lincoln, USA. Data were analyzed as a split-split-plot with analysis of variance (ANOVA), using the General Linear Model procedures of the Statistical Analysis System. The nitrogen content of the leaf tissue is variable in creeping bentgrass fairway turf with clip-ping recycles, nitrogen application rate and time after establishment. Leaf tissue nitrogen content increased with clipping return and nitrogen rate. Plots treated with clipping return had 8% and 5% more nitrogen content in the leaf tissue in 1989 and 1990, respectively, as compared to plots treated with clipping removal. Plots applied with high-N level (25g N $m-^2$ $yr-^1$)had 10%, 17%, and 13% more nitrogen content in leaf tissue in 1989, 1990, and 1991, respectively, when compared with plots applied with low-N level (5g N $m-^2$ $yr-^1$). Overall observations during the study indicated that leaf tissue nitrogen content increased at any nitrogen rate with time after establishment. At the low-N level treatment (5g N $m-^2$ $yr-^1$ ), plots sampled in 1991 had 15% more leaf nitrogen content, as compared to plots sampled in 1989. Similar responses were also found from the high-N level treatment (25g N $m-^2$ $yr-^1$ ).Plots analyzed in 1991 were 18% higher than that of plots analyzed in 1989. No significant treatment effects were observed for soil nitrogen content over the first 3 years after establishment. Strategic management application is necessary for the golf course turf, depending on whether clippings return or not. Different approaches should be addressed to turf fertilization program from a standpoint of clipping recycles. It is recommended that regular analysis of the soil and leaf tissue of golf course turf must be made and fertilization program should be developed through the interpretation of its analytic data result. In golf courses where clippings are recycled, the fertilization program need to be adjusted, being 20% to 30% less nitrogen input over the clipping-removed areas. Key words: Agrostis palustris Huds., 'Penncross' creeping bentgrass fairway, Irrigation frequency, Clipping return, Nitrogen rate, Leaf nitrogen content, Soil nitrogen content.

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