• Title/Summary/Keyword: time-clipping

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An Analysis of Categorical Time Series Driven by Clipping GARCH Processes (연속형-GARCH 시계열의 범주형화(Clipping)를 통한 분석)

  • Choi, M.S.;Baek, J.S.;Hwan, S.Y.
    • The Korean Journal of Applied Statistics
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    • v.23 no.4
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    • pp.683-692
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    • 2010
  • This short article is concerned with a categorical time series obtained after clipping a heteroscedastic GARCH process. Estimation methods are discussed for the model parameters appearing both in the original process and in the resulting binary time series from a clipping (cf. Zhen and Basawa, 2009). Assuming AR-GARCH model for heteroscedastic time series, three data sets from Korean stock market are analyzed and illustrated with applications to calculating certain probabilities associated with the AR-GARCH process.

Experimental Study on the Effect of Temporary Clipping on the Histological Changes of the Arterial Walls of Rats

  • Koh, Hyeon-Song;Kwon, O-Yu
    • Biomedical Science Letters
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    • v.13 no.2
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    • pp.111-117
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    • 2007
  • Temporary occlusion of the parent artery or feeding artery is an useful method in microsurgery for cerebrovascular diseases. The advantages of the temporary clipping for intracranial aneurysm surgery have already been proven by many experimental and clinical reports. Currently, there are two methods of temporary clipping: 1) intermittent clipping, 2) continuous clipping. In many previous studies, the intermittent, repeated clipping technique was reported to reduce ischemic damage to the brain, but it is still debated. On the other hand, a comparison of the histological changes on the arterial wall between each clipping method has not been sufficiently reported yet. So the authors performed experimental temporary clipping on the common carotid and femoral arteries of about 25 rats using the Sugita temporary mini-clip. The specimens were divided into two major groups and seven subgroups: Group I (I-1, I-2, I-3, I-4, intermittent clippings for 5 minutes were done once, twice, three times, and few times), and Group C (C-10, C-15, C-20, continuous clippings for 10, 15, 20 minutes, respectively). The reperfusion time after the temporary clipping was the same as the clipping duration. Under light microscope, the histological findings by Hematoxylin-Eosin staining were examined in all specimens, which were obtained at each time interval after temporary clipping. Then the histological changes of the arterial walls by two different methods were compared with the normal specimen. The results suggest that intermittent temporary clipping is less damaging on the arterial wall than single continuous clipping.

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Octree Generation and Clipping Algorithm using Section Curves for Three Dimensional Cartesian Grid Generation (삼차원 직교 격자 생성을 위한 단면 커브를 이용한 옥트리 생성과 셀 절단 알고리듬)

  • Kim, Dong-Hun;Shin, Ha-Yong;Park, Se-Youn;Yi, Il-Lang;Kwon, Jang-Hyuk;Kwon, Oh-Joon
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.6
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    • pp.450-458
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    • 2008
  • Recently, Cartesian grid approach has been popular to generate grid meshes for complex geometries in CFD (Computational Fluid Dynamics) because it is based on the non-body-fitted technique. This paper presents a method of an octree generation and boundary cell clipping using section curves for fast octree generation and elimination of redundant intersections between boundary cells and triangles from 3D triangular mesh. The proposed octree generation method uses 2D Scan-Converting line algorithm, and the clipping is done by parameterization of vertices from section curves. Experimental results provide octree generation time as well as Cut-cell clipping time of several models. The result shows that the proposed octree generation is fast and has linear relationship between grid generation time and the number of cut-cells.

Influence of Sowing and Harvest Date on Yield and Nutritional Quality of Forage Rye

  • Kwon, Byung-Sun;Shin, Dong-Young
    • Plant Resources
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    • v.7 no.3
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    • pp.206-210
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    • 2004
  • In order to find out the optimum harvest (dipping) date combined with sowing date on yield and nutrient quality of forage rye which is suitable at the Southern part of Korea, Paldanghomil variety was grown Sep. 2001 to May 2002 at Sunchon National University, and yield and nutrient quality of plant were observed. As harvest date and sowing date were delayed, the plant length was longest, number of leaves per plant was increased in the time of May 20 clipping. Fresh yield was the heaviest in the time of May 20 clipping and Oct. l0 sowing, and the most dry matter yield was the heaviest in the time of May 20 clipping and Oct. 10 sowing. Content of crude protein was the highest and that of crude fiber such as NDF, ADF, hemicellulose, cellulose and lignin were the lowest in the late time of clipping and sowing. Further more IVDMD was high and dry matter yield and digestible dry matter yield were the highest in the time of May 20 dipping and Oct. 10 sowing. Judging from the results reported above, at optimum harvest (dipping) date combined with sowing date for yield and nutrient quality of forage rye seemed to be the time of May 20 clipping and Oct. 10 sowing.

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The Effect of Foliage Clipping on the Growth and the Agronomic Characteristics, as Affected by its Time, Degree, and Nitrogen Top-Dressing, in Rice plants (절엽의 시기 및 정도, 그리고 절엽 후의 시비가 수도의 생육 및 수량제형질의 변화에 미치는 영향)

  • Eun-Woong Lee;Yong-Woong Kwon;Pyeong-Ki Yim
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.4 no.1
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    • pp.81-91
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    • 1968
  • To investigate the effects of foliage clipping time, degree, and nitrogen top-dressing after clipping on the growth and the agronomic characteristics, rice plants grown under ordinary cultural practices were clipped at the maximum tiller stage, 10 days prior to, and after that stage, respectively, with varying clipping, height, as 0, 1/3, 1/2, and 2/3 of plant height. And nitrogen was top-dressed at the rate of 0, 2, 4, 6 kg per 10 are immediately after clipping. The variety used was "Jinheung". The results obtained are outlined as follows: 1. Effect of clipping on the growth of rice plant: The subsequent growth was quite rapid during 10 days after clipping, and resulted, on the whole, in nearly complete recovery of defoliation by 20 days after clipping. a) Generally, the later the clipping time, the more growth accelerated. Rice plants clipped before the differentiation of ear primordia nearly recovered the damage, and in certain cases exceeded non-clipped plants in height. But the height of the rice plant clipped after the differentiation of ear primordia was somewhat smaller than that of non-clipped. b) Growth rate was rather rapid in the case of severe cutting, and the height of slightly clipped plants was taller than that of non-clipped plants. However, rice plants clipped to the extent of 2/3 of plant height did not fully recover the damage of defoliation compared to non-clipped plants. c) Nitrogen dressing was effective to rapid recovery of defoliation, the effect increasing with the increasing amount of application. d) Ear-heading was delayed in clipped plots, and this tendency was more apparent with later clipping time, more severe clipping, and increased amounts of nitrogen application after cutting. The range was 6 days at maximum. 2. Effect of defoliation on the yield and its components of rice plants: The yield response to clipping varied somewhat with its time, degree, and nitrogen application after cutting: yield increase of about 10% and decreasement of about 25% at maximum compared to the control plot. Grain yield of most plots was decreased. a) Clipping before the differentiation of ear primordia did not much affect the agronomic characteristics of rice plants. However, clipping after that growth stage decreased culm length, number of panicles, number of spikelets per panicle, and maturing rate of grain to some extent. Consequently this treatment resulted in decrease of about 10% in grain and straw production in spite of increase in panicle length and effective tillering rate. b) Slight, clipping decreased number of spikelets per panicle a little, and the yield of grain and straw by 4-5%, although effective tillering rate was somewhat increased. With severe clipping, panicle kngth, number of panicles, and number of spikelets per panicle decreased more, and the yield of grain and straw decreased about 10%. c) Nitrogen dressing after clipping at the rate of 2 kg per 10 are was effective in increasing grain yield. Nitrogen application over the rate of 4 kg per 10 are increased culm length, number of spikelets per panicle, and straw production, but this decreased the maturing rate, and the 1, 000-grains weight to some extent and resulted in decrease of grain yield.

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Studies on the Flowering and Maturity in Sesame (Sesamum indicum L.) IV. Effects of Foliage Clipping on the Seed Maturity (참깨의 개화.등숙에 관한 연구 IV. 적엽처리가 참깨의 등숙에 미치는 영향)

  • Lee, Jung-Il;Kang, Chul-Whan;Son, Eung-Ryong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.30 no.2
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    • pp.165-173
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    • 1985
  • The objectives of the study were to investigate the effects of foliage clipping on photosynthesis and grain filling for branch and non branch types under the polyethylene film mulch and non mulch conditions in mono cropping and second cropping after barley in sesame (Sesamum indicum L.), and to improve poor grain filling at later flowering time utilizing these data. One thousand grain weight was more decreased in branch type than in non branch type, in polyethylene film mulch condition than in non mulch condition, and in second cropping after barley than in mono cropping by clipping lower part foliage. Twentyfive percent clipping of lower part foliage showed a little increase than no clipping. Matured grain rate also showed same tendency between branch and non branch type and between mono cropping and second cropping after barley as well as 1,000 grain weight except for polyethylene film mulch. Matured grain rate of 25% foliage clipping at 30 days after flowering in non branch type presented a little increase but decreased in branch type. Clipping of higher part leaves were so serious decrease of matured grain rate that higher part leaves at late maturing time have a major role in photosynthesis. Matured grain rate of foliage clipping at 10 days after flowering was decreased in all treatments. Chlorophyll content of higher part leaves at 50% lower part foliage clipping presented 39% increase compared to same positioned leaves of non treatment, and 66% increase by 50% higher part foliage clipping in lower part leaves. Photosynthetic activity was 58% more increased in 50% lower part foliage clipping than no clipping, but seriously decreased in 50% higher part foliage clipping. Therfore, photosynthates of remained lower part leaves could not only support their own demands, but also any contribution to translocation of photosynthates from source to sink at late maturing time. Harvest index was 28% increased in 25% lower part foliage clipping and 13% decreased in 50% higher part foliage clipping compared to no clipping. Leaf area was 48% increased in 50% lower part foliage clipping compared to the same positioned leaves of no clipping, and only 5% increased in higher part foliage clipping. Productivity by foliage clipping compared to non treatment, was highly decreased in branch type than in non branch type, in second cropping after barley than in mono cropping. Little difference was detected between polyethylene film mulch and non mulch conditions. Twenty five percentage of lower part foliage clipping on mono cropping of non branch type appeared 5% and 8% yield increase in each of polyethylene film mulch and non mulch conditions compared to no clipping, and all decreased in other treatments. Mean loss of productivity by foliage clipping at 10 days after flowering was serious than clipping at 30 days after flowering. As the result, contribution to photosynthesis of source at 10 days after flowering are larger than that at 30 days after flowering in sesame. Fifty percent lower part foliage clipping at 10 days after flowering showed so the most serious yield decrease that lower part leaves at that time were considered as the main role leaves for photosynthesis.

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Studies on Productivity and Nutrient Quality of Forage Rape (Brassica napus Subsp. oleifera) VI. Influence of Sowing and Harvest Date on Yield and Nutritional Quality (사초용 유채 생산성과 사료가치에 관한 연구 VI. 파종기별 예취시기가 수량 및 영양가치에 미치는 영향)

  • Ahn, Gae-Soo;Kwon, Byung-Sun;Lee, Jung-Il
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.4
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    • pp.335-340
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    • 1989
  • In order to find out the optimum harvest (clipping) date combined with sowing date on yield and nutrient Quality of forage rape which is suitable at the southern part of Korea, Velox, introduced variety was grown from Sep. 1987 to May 1988 at Sunchon National University, and yield and nutrient Quality of plant were observed. As harvest date and sowing date were delayed, the plant length was longest, number of branch and leaves per main stem were increased in the time of full bloom clipping and Sep. 24 sowing but stem diameter was thickest in the early sowing. Fresh yield was heaviest in the time of flowering clipping and Sep. 24 sowing but the most dry matter yield was heaviest in the time of full bloom clipping and Sep. 24 sowing. Content of crude protein was highest and that of crude fiber such as NDF, ADF, hemicellulose, cellulose and lignin were lowest in the late time of clipping and sowing. Further more IVDMD was high and dry matter yield and digestible dry matter yield were highest in the time of flowering clipping and Sep. 24 sowing. Judging from the results reported above, at optimum harvest (clipping) date combined with sowing date for yield and nutrient Quality of forage rape seemed to be the time of flowering clipping and Sep. 24 sowing.

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Performance analysis on the nonlinear distortion in OFCDM downlink system using clipped multilevel-PSK (Clipped multilevel-PSK를 이용한 OFCDM 순방향 링크에서 비선형 왜곡에 대한 성능 분석)

  • 안치훈;최영관;장승훈;김동구
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.11
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    • pp.17-26
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    • 2003
  • To reduce the nonlinear distortion of high power amplifier(HPA) in down link OFCDM system to employ time domain spreading, we apply technology which transmits MPSK(Multilevel-PSK) signal after clipping on multilevel input signal of IFFT subcarrier. In case that the nonlinear distortion of HPA is considered in AWGN channel, performacne of clipping OFCDM system using extended m sequence is over 2.2㏈ better than that of OFCDM system using extended m sequence when the number of user is 8 and 16. In case that the nonlinear distortion of HPA is considered in quasi-static channel, performacne of clipping OFCDM system using extended m code is over 2㏈ better than that of OFCDM system using extended m sequence when the number of user is 8 and 16.

Performance Evaluation of a Time- and Frequency-Domain Clipping-Based PAPR Reduction Scheme in a DVB-T System (DVB-T 시스템에서 시간 및 주파수 영역 클리핑 기반의 PAPR 감소기법의 성능평가)

  • Seo, Man-Jung;Im, Sung-Bin;Kim, Na-Hoon;Cho, Jun-Kyung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.1
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    • pp.24-31
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    • 2007
  • DVB-T (Digital Video Broadcasting-Terrestrial) is an important multimedia broadcasting technology capable of high data-rate transmission and adopted by Europe. OFDM (Orthogonal Frequency Division Multiplexing) is the backbone technique employed in DVB-T to support multimedia services that have various bandwidths. Unfortunately, an OFDM signal has a large PAPR (Peak-to-Average Power Ratio). In this paper, we investigate the performance of a simple PAPR reduction scheme for the DVB-T system, which requires no change of a receiver structure or no additional information transmission. The approach we employed is clipping in the time and frequency domains. The time-domain clipping is carried out with a predetermined clipping level while the frequency-domain clipping is done within EVM (Error Vector Magnitude). This approach is suboptimal with lower computational complexity compared to the optimal method. The simulation results demonstrate that the proposed one is getting more effective at lower modulation levels and with more allowed constellation error.

Chemical Composition, Herbage Yield and Nutritive Value of Panicum antidotale and Pennisetum orientale for Nili Buffaloes at Different Clipping Intervals

  • Sarwar, Muhammad;Mahr-un-Nisa, Mahr-un-Nisa;Khan, M. Ajmal;Mushtaque, M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.2
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    • pp.176-180
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    • 2006
  • This study was carried out to establish clipping interval of Pennisetum orientale (PO) and Panicum antidotale (PA) to get maximum biomass production with optimal nutritional value for Nili buffaloes. Two clipping intervals i.e. $CI_1$, and $CI_2$ (clipped after every one and two months, respectively) were studied for both grasses. The data on various parameters were compared with PO and PA each clipped at 4 months of age (control). Leaf to stem ratio in both PO and PA declined with increasing clipping interval. Concentration of dry matter (DM) and organic matter (OM) increased (p<0.05) whereas crude protein contents decreased with increasing clipping interval in both grasses. Crude protein and dry herbage yields in PO and PA increased (p<0.05) with increasing clipping interval. The DM and neutral detergent fiber (NDF) digestibilities of PO and PA in ruminally cannulated buffalo bulls decreased (p<0.05) due to more lignification with increasing clipping interval. Ruminal extent of digestion, rate of disappearance of DM and neutral detergent fiber of PO and PA decreased in buffaloes while ruminal lag time of these nutrients increased significantly (p<0.05) with increasing clipping interval. The results from the study imply that two month clipping interval for both PO and PA grasses favored higher biomass with greater nutritional value for Nili buffaloes and sustained grass vigor.