• Title/Summary/Keyword: National Science Fair

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Chemical Characteristics of Surface Soil and Mineral Content of Lawn in Some Golf Course in Kyonggi Province (경기도 수개 골프장의 표토 토양화학성과 잔디의 무기성분함량)

  • Choi, Byung-Ju;Shim, Jai-Sung;Ju, Yeong-Hee;Park, Hoon
    • Asian Journal of Turfgrass Science
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    • v.7 no.2_3
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    • pp.129-135
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    • 1993
  • Surface soils and aerial parts of Korean lawn(Zoysia koreana) at normal fair way of 4 golf courses and yellow discolored fairway of one golf course in Kyonggi province were taken at and analyzed for mineral contents in soil Mg and Ca were most deficient while EC was too high and phosphorus was exess. There were significant positive correlation between pH and Ca and between EC and total N. There was no consistent simple correlation between single component in soil and plant, indicating the involvement of multi-minerals in one mineral absorption. m mineral contents of aerial part Mg was severely low. potassium moderately but Ca was normal, Mg and Ca showed significant correlation in aerial part, yellow-discolored lawn showed the lowest content of Mg in aerial part and surface soil. Very high N and high phosphorus in aerial part inspite of low P in soil. The above facts indicates Mg deficiency in fair way soils in most golf courses resulting in yellow-discoloration in lawn.

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A Study on Current Status of Caution Labels on Cooking Utensils Made from Plastics and Glass (플라스틱 및 유리제 식품용 기구의 사용 시 주의사항에 대한 라벨 표시 실태)

  • Kim, Myung-Shin;Kim, Hyo-Chung;Kim, Mee-Ra
    • Journal of the East Asian Society of Dietary Life
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    • v.20 no.4
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    • pp.628-638
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    • 2010
  • This study examined the current status of caution labels on cooking utensils made from plastics or glass, toward suggesting improvements in labeling for consumer's safe use. Distributors were categorized into four types, plastic kitchen utensils were categorized into seven types according to usage, and glass kitchen utensils were categorized into two types. Generally, the percentage of cooking utensils made from plastics or glass that have caution labels were not high. For the types of labels on cooking utensils made from plastic and glass, stickers were the most frequently used, and of these, a high percentage scored "fair" in label perception. On the basis of these results, regulations are needed to strengthen caution labels for kitchen utensils.

Performance Improvement of TCP Over High-speed Networks (고속 네트워크에서 TCP 성능 개선 기법)

  • Yang, Eun-Ho;Kim, Chong-Kwon
    • Annual Conference of KIPS
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    • 2005.05a
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    • pp.1271-1274
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    • 2005
  • Fast long-distance network 에서 기존 TCP 의 혼잡 제어 (congestion control) 알고리즘은 대역폭을 효과적 사용하지 못하는 문제점을 가지고 있다. 대역폭을 효과적으로 사용하기 위해서 TCP 혼잡 제어를 수정한 다양한 프로토콜들이 제안되었다. 이러한 프로토콜들은 디자인 시 주로 bandwidth scalability, TCP friendliness, 그리고 RTT fairness 와 같은 세 가지의 특성을 고려하고 있다. 하지만 제안된 프로토콜들은 어떤 것도 trade-off 관계로 있는 이 세 가지 특성을 동시에 만족시키지 못한다. 본 논문에서는 혼잡 제어 알고리즘의 증가 규칙 (increase rule)에 RTT 를 직접 반영함으로써 위 세가지 요구사항을 동시에 만족시키는 EIMD (Exponential Increase/ Multiplicative Decrease)라고 하는 새로운 TCP 혼잡 제어 알고리즘을 제안한다. EIMD 는 패킷 손실이 없는 한, 지수적으로 윈도우를 증가시켜 효과적으로 대역폭을 사용하면서도, 패킷손실 직전의 윈도우 크기, $W_{max}$ 에 반비례하게 윈도우를 증가시킴으로써 fair share 에 빠르게 수렴할 수 있다는 특성을 갖는다. 모의실험을 통해 제안된 프로토콜이 fast long-distance network 에서 위 4 가지 특성들을 모두 만족하는지 검증한다

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Dose-related Effects of Follicle Stimulating Hormone on Superovulation in Indigenous Cows of Bangladesh

  • Hossein, M.S.;Shamsuddin, M.;Bhuiyan, M.M.U.;Khan, A.H.M.S.I.;Bari, F.Y.
    • Journal of Embryo Transfer
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    • v.17 no.2
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    • pp.123-128
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    • 2002
  • The present study aimed at determining the effective dose of Folltropin, a follicle timulating hormone (FSH), on superovulation in indigenous cows of Bangladesh. Fifteen regularly cycling 5~7 years old dry cows, weighing 200~250 kg with 2.5~3.0 body condition scores (BCS) were divided into three groups (n=5). Individual groups were superovulated with 100, 200 or 300 mg of Folltropin per animal. The superovulation treatment was initiated at Day 10 or Day 11 of the estrous cycle (Day 0=day of estrus). Alfaprostol (6 mg) was injected to each cow 72 h after the initiation of superovulation treatment to induce eestrus. After confirming standing estrus, the cows were inseminated 2~3 times, 12 h apart, depending on the duration of estrus. At Day 6 or Day 7, individual horns of the uterus were flushed with 150~200 $m\ell$ of phosphate buffered saline supplemented with BSA (0.2%), penicillin (100 IU/$m\ell$) and streptomycin (100 $\mu\textrm{g}$$m\ell$) using a two-way foley catheter. The embryos were concentrated, removing the excess medium through an embryo filter, and identified under a stereomicroscope. The identified embryos were collected, washed four times, evaluated and graded as excellent, good, fair or poor. The excellent, good and fair embryos were considered as transferable quality embryos. The mean (range). numbers of embryos collected vs. transferable quality embryos far 100, 200 and 300 mg of Folltropin were 4.5 (1~10) vs. 3.5 (1~8); 2.5 (1~4) vs. 1 (0~2) and 0.0 (0~0) vs. 0.0 (0~0), respectively, Folltropin at a dose of 100 or 200 mg produced suitable ovarian stimulation for superovulation in indigenous zebu cows of Bangladesh. A dose of 300 mg or more Folltropin consistently caused preovulatory corpora lutea formation in the ovaries and resulted in zero embryo recovery.

TCP-GT: A New Approach to Congestion Control Based on Goodput and Throughput

  • Jung, Hyung-Soo;Kim, Shin-Gyu;Yeom, Heon-Young;Kang, Soo-Yong
    • Journal of Communications and Networks
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    • v.12 no.5
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    • pp.499-509
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    • 2010
  • A plethora of transmission control protocol (TCP) congestion control algorithms have been devoted to achieving the ultimate goal of high link utilization and fair bandwidth sharing in high bandwidth-delay product (HBDP) networks. We present a new insight into the TCP congestion control problem; in particular an end-to-end delay-based approach for an HBDP network. Our main focus is to design an end-to-end mechanism that can achieve the goal without the assistance of any network feedback. Without a router's aid in notifying the network load factor of a bottleneck link, we utilize goodput and throughput values in order to estimate the load factor. The obtained load factor affects the congestion window adjustment. The new protocol, which is called TCP-goodput and throughput (GT), adopts the carefully designed inversely-proportional increase multiplicative decrease window control policy. Our protocol is stable and efficient regardless of the link capacity, the number of flows, and the round-trip delay. Simulation results show that TCP-GT achieves high utilization, good fairness, small standing queue size, and no packet loss in an HBDP environment.

Ecological Health Assessment Based on Fish Assemblages Along with Total Mercury Concentrations of Zacco platypus in Miho Stream (어류 군집을 이용한 미호천의 생태 건강성 평가 및 피라미(Zacco platypus)의 총수은 함량)

  • Lee, Jae-Hoon;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.43 no.2
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    • pp.288-297
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    • 2010
  • This study was to evaluate the ecological stream health through the Multimetric Fish Assessment Index (MFAI) along with fish fauna analysis based on the tolerance and trophic guilds at Miho stream in 2008 and 2009. Also, we analysed total mercury concentration in fish tissues to examine heavy metal contamination. Total sampled fish were 40 species and 2,557 individuals and Zacco platypus was the most dominant with 35% relative abundance. It was sampled with 11.4% RA for Korean endemic species (10 species 291 individuals) less than average RA 39.3% for the Geum river watersheds. According to the tolarance guild analysis, tolerant species was more dominant with 58.9% RA (15 species, 1,507 individuals) than sensitive species with 6.6% RA. Trophic guild analysis also suggested that omnivores were more dominant (60.5% RA) than insectivores (31.5% RA). Riffle-benthic species was also sampled with 7.7% RA. Ecological stream health based on the MFAI were averaged 25.3 (n=3) with fair-poor condition in 2008 and also 26.3 (n=3) with fair condition in 2009, just slightly increased than 2008. Qualitative habitat evaluation index was averaged 134 (n=3) with fair condition but most of sites had sediment accumulation that reflected substrate degradations proceeding. From the result of total mercury accumulation in fish tissues, kidney and liver tissues showed the highest but the lowest for gill tissues. Overall mercury concentration were not exceed the national standards by Korean Federation of Drug and Administration (KFDA). Consequently, our result could correspond with the characteristics of Miho stream where point sources such industrial complexes and wastewater treatment plant widely distributed around the stream along the gradient of up and downstream.

Effects of stage and quality of embryo, synchrony between donor and recipient and difficulty of transfer on pregnancy rate following non-surgical transfer of frozen-thawed bovine embryos (젖소 동결수정란의 비외과적 이식에 있어서 수정란의 상태 및 이시조건이 수태율에 미치는 영향)

  • Lee, Eun-song;Jo, Choong-ho;Hwang, Woo-suk
    • Korean Journal of Veterinary Research
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    • v.29 no.3
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    • pp.361-371
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    • 1989
  • This study was performed to investigate the effects of stage and quality of embryo, synchrony between donor and recipient and difficulty of transfer on pregnancy rate following non-surgical transfer of frozen-thawed bovine embryos. The results were as follows; 1. The overall pregnancy rate of this experiment was 63.4% and that of heifers(73.1%) was higher than that of cows(46.7%). 2. The pregnancy rates of recipients transferred with morulae, early blastocysts and blastocysts were 50.0%, 64.7% and 71. 4%, respectively. 3. The pregnancy rate of recipients transferred with good embryos(67.9%) was higher than that of recipients transferred with fair embryos(53.8%). 4. The pregnancy rates of embryos transferred to left and right uterine horn were 63.2% and 63.6%, respectively. 5. The pregnancy rate of recipients in estrous synchrony 0(76.2%) was higher than those of recipients in synchrony -1(55.6%) and +1(44.4%). 6. The pregnancy rate of recipients transferred with 2 embryos (71. 4%) was higher than that of recipients transferred with 1 embryo(61.8%). 7. The pregnancy rate of embryos transferred to uterine tip (72.0%) was higher than that of embryos transferred to uterine base(50.0%). 8. Ease of transfer was ranked to a scale of one to three on the basis of increasing difficulty. Transfers ranked as ease score 1 accounted for 77.8% of pregnancies and had higher pregnancy rate than ease score 2(66.7%) or 3(45.5%). 9. The pregnancy rate of recipients with excellent corpus luteum(CL) (70.0%) was higher than those of recipients with good CL(61.1%) or fair CL(61.5) %. In reviewing above results, it was considered that the factors such as embryo stage, embryo quality, estrous synchrony, corpus luteum quality, transfer site within uterus, recipient's parity and ease score affected the pregnancy rate after non-surgical transfer of frozen-thawed bovine embryos.

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CPU Usage Analysis According to the Task Group in Android Mobile (안드로이드 단말의 태스크 그룹에 따른 CPU 점유율 분석)

  • Kim, Myungsun;Lim, Jintaek;Park, Daedong
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2013.01a
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    • pp.9-12
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    • 2013
  • 리눅스 기반 안드로이드 단말에서는 CFS(Completely Fair scheduler)가 사용되고 있다. 그리고 CFS는 태스크의 nice값 조절을 통해서 응용프로그램의 CPU 점유율을 제어할 수 있다. 하지만 안드로이드를 업그레이드할 때마다 수많은 태스크의 nice값을 적절하게 맞추는 일은 매우 어려운 일이다. 이러한 문제를 해결하기 위하여 안드로이드 단말은 리눅스의 cgroup(control group)을 사용하여 태스크들을 그룹으로 나눈다. 고성능과 빠른 응답 특성이 필요한 태스크들을 apps 그룹에 할당하여 높은 CPU 점유율을 보장하고, 그렇지 않은 태스크들을 background 그룹에 할당한다. 하지만 안드로이드의 버전이 업그레이드 되면서 각 그룹에 속한 태스크들에도 변화가 생긴다. 그 결과 동일하게 제작된 태스크들의 CPU 점유율이 달라지게 되고 예기치 못한 성능 저하가 발생할 수 있다. 본 연구에서는 안드로이드 버전 향상에 따라 동종 태스크들이 이전 버전에서보다 성능이 하락하는 현상의 원인을 파악하였다. 아울러 분석과 실험을 통하여 태스크의 nice 값보다 그룹 스케줄링 메커니즘이 어떻게 태스크의 CPU 점유율을 결정 짓는지 규명하였다.

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Evaluation of Generator Reactive Power Pricing Through Optimal Voltage Control under Deregulation

  • Jung Seung-Wan;Song Sung-Hwan;Yoon Yong Tae;Moon Seung-Il
    • KIEE International Transactions on Power Engineering
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    • v.5A no.3
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    • pp.228-234
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    • 2005
  • This paper presents the evaluation of reactive power pricing through the control of generator voltages under the assumption that the reactive power market has been transformed into the real power market. By applying the concept of economic dispatch, which minimizes the total cost of real power generation to reactive power generation, the algorithm for implementing reactive power pricing is proposed to determine the optimum voltage profiles of generators. It consists of reactive power voltage equation, the objective function that minimizes the total cost of reactive power generation, and linear analysis of inequality constraints in relation to the load voltages. From this algorithm, the total cost of the reactive power generation can be yielded to the minimum value within network constraints as the range of load voltages. This may provide the fair and reasonable price information for reactive power generation in the deregulated electricity market. The proposed algorithm has been tested on the IEEE 14-bus system using MATLAB.

Design, Analysis and Evaluation of A New Energy Conserving MAC Protocol for Wireless Sensor Networks

  • Lim, Sangsoon;Kang, Young-Myoung;Jeong, Jiwoong;Kim, Chong-Kwon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.12
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    • pp.3046-3060
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    • 2012
  • Low power listening (LPL) MAC protocols based on duty-cycling mechanism have been studied extensively to achieve ultra low energy consumption in wireless sensor networks (WSNs). Especially, recent ACK-based LPL schemes such as X-MAC employ strobe preambles and an early ACK, and show fair performances in communications and energy efficiencies. However, the state-of-the-art ACK-based LPL scheme still suffers from collision problems due to the protocol incompleteness. These collision effects are not trivial and make WSNs unstable, aggravate energy consumptions. In this paper, we propose two novel schemes; (i) ${\tau}$-duration CCA to mitigate the collision problem in ACK-based LPL MAC protocols. (ii) Short Preamble Counter (SPC) to conserve more energy by reducing unnecessary overhearing. We demonstrate the performance improvement of our scheme via a mathematical analysis and real-time experiments. Both analysis and experimental results confirm that our proposed scheme saves energy by up to 36% compared to the naive ACK-based LPL MAC protocol thanks to ${\tau}$-duration CCA and SPC.