• Title/Summary/Keyword: 비옥토

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Performance Evaluation of Octonion Space-Time Coded Physical Layer Security in MIMO Systems (MIMO 시스템에서 옥토니언 시공간 부호를 이용한 물리계층 보안에 대한 성능 분석)

  • Young Ju Kim;BeomGeun Kwak;Seulmin Lim;Cheon Deok Jin
    • Journal of Broadcast Engineering
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    • v.28 no.1
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    • pp.145-148
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    • 2023
  • Open-loop Octonion space-time block code for 4 transmit antenna system is considered and random phases are applied to 4 transmit antennas for physical layer security. When an illegal hacker estimates the random phases of 1 through 4 transmit antennas with maximum likelihood (ML), this letter analyzes the bit error rate (BER) performances versus signal-to-noise ratio (SNR). And the Octonion code in the literature[1] does not have full orthogonality so, this letter employs the perfect orthogonal Octonion code. When the hacker knows that the random phases are 2-PSK constellations and he should estimate all the 4 random phases, the hacking is impossible until 100dB. When the hacker possibly know that some of the random phases, bit error rate goes down to 10-3 so, the transmit message could be hacked.

조경수의 병해충 - 밤나무에 피해를 주는 해충(1)

  • 최광식
    • Landscaping Tree
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    • s.88
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    • pp.8-11
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    • 2005
  • "가을을 상징하는 과일 중 밤나무의 밤 송아리처럼 가을을 대변하는 전령사는 드물 것이다. 가을 빛 영롱한 숲속에서 하늘과 당과 구름과 별과, 햇빛과 바람이 시를 읊고 있는 가을은 가시 속에 아롱진 꿈이 밤송이 되어 바람결에 빗방울처럼 떨어져도 겨울에 먹을 음식이 다람쥐와 청설모에게는 모자라는 안타까움이 인간의 욕심을 새삼 느끼게 하는 구나! 이렇게 우리에게 넉넉함과 즐거움을 주는 밤나무는 양수로서 바람이 적은 산록이나 저지대의 토심이 깊은 비옥토에서 잘 자라며, 맹아력이 좋고 수세가 강건하다. 과실은 예로부터 식용대용으로 각종음식을"

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Effect of Metal Complexes as a Catalyst on Curing Behavior and Mechanical Properties of Silica Filled Epoxy-Anhydride Compounds (촉매로서 금속 착화합물이 실리카가 충전된 에폭시-산무수물 복합체의 경화 거동 및 물성에 미치는 영향)

  • Seo, Byeongho;Lee, Dong-Hoon;Lee, Noori;Do, Kiwon;Ma, Kyungnam;Kim, Wonho
    • Elastomers and Composites
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    • v.49 no.1
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    • pp.59-65
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    • 2014
  • In this study, in order to complete curing reaction of the molding compound comprising an epoxy/anhydride at $71^{\circ}C$ for 40 hours, metal coordination complexes such as cobalt (II) acetylacetonate, potassium acetylacetonate, iron (III) acetylacetonate and chromium (III) octoate as a catalyst were applied to the epoxy/anhydride compounds respectively. The weight ratio of an epoxy part/an anhydride part was adjusted to improve the mechanical properties of the molding compound. According to the experimental results, an epoxy/anhydride compound containing chromium (III) octoate showed a high conversion at $71^{\circ}C$ for 40 hours as well as a proper processability at room temperature among the several metal coordination complexes. For the mechanical properties of the cured epoxy/anhydride compound, the compounds containing weight ratio from 0.9/1 to 0.5/1 of the epoxy part/anhydride part with chromium (III) octoate showed the high flexural strength, and higher compressive strength was shown with increasing of the hardener part.

Dynamic Modeling and Control Techniques for Multi-Rotor Flying Robots (멀티로터 무인비행로봇 동역학적 모델링 및 제어기법 연구)

  • Kim, Hyeon;Jeong, Heon Sul;Chong, Kil To;Lee, Deok Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.2
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    • pp.137-148
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    • 2014
  • A multi-rotor is an autonomous flying robot with multiple rotors. Depending on the number of the rotors, multi-rotors are categorized as tri-, quad-, hexa-, and octo-rotor. Given their rapid maneuverability and vertical take-off and landing capabilities, multi-rotors can be used in various applications such as surveillance and reconnaissance in hostile urban areas surrounded by high-rise buildings. In this paper, the unified dynamic model of each tri-, quad-, hexa-, and octo-rotor are presented. Then, based on derived mathematical equations, the operation and control techniques of each multi-rotor are derived and analyzed. For verifying and validating the proposed models, operation and control technique simulations are carried out.

The effect of potash on the growth and yields of soybean at different level of soil fertility and application of fertilizer (토양(土壤)과 시비(施肥)를 달리할때 대두생육(大豆生育)에 미치는 가리(加里)의 영향(影響))

  • Cho, C.Y.;Maeng, D.W.
    • Applied Biological Chemistry
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    • v.10
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    • pp.107-112
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    • 1968
  • In order to study the effect of potash on the growth and yields of Soybean at different level of soil fertility and application of fertilizer (nitrogen, phosphate and calcium), $2^3$factorical experiment was carried out by pat culture with variety 'Chang-dan-baec-muc' which is most spreaded variety in Korea. The experiment consisted of five replications in a randomized block experiment with three factors (soil, fertilization and potash). Treatment were at two levels; infertile and fertile soil, none and some of fertilization and potash. Thus, the experiment comprised eight treatment combinations which consisted of all combinations. The results of this experiment are as follows: 1. No effect of each of three factors on flowering date was found. 2. Leaf-yellowing and maturing date was quickened on the fertile soil but no effect of fertilization and potash was found. 3. More premature leaf-yellowing was found on the fertile soil. 4. Deeper leaf colour cuss showed on the fertile soil and in the case of fertilization but no effect of potash was found. 5. Increasing tendency of following character: length and width of leaf, height and dia of stem, number of branches and pods; was most remarkable on the fertile soil. Application of fertilizer showed also remarkable tendency of increasing, while increasing tendency of potash was the least. 6. Same tendency was found with following charactors; weight of total plant. stem and shell, and commercial grains, weight of 100 grain and number of commercial grains. 7. As the results of analysis of variance for weight of commercial grain it, was found the teach of the three factors increased soybean yields significantly (weight of commercial grain) but the effect of potash was less than the other two factors. No significant interaction was found among three factors. 8. Greater effect of potash on increasing soybean yields was found on the fertile soil, and in the case of fertilization.

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A Study on the Planting and Cultivate of Hong Man-Seon(1643~1715)'s 'Salimkyungjae (山林經濟, The Economy of Forest)' (홍만선의 '산림경제(山林經濟)'에서 본 조경식물 재배(종수법(種樹法))와 가꾸기(양화법(養花法)))

  • Shin, Sang Sup
    • Korean Journal of Heritage: History & Science
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    • v.44 no.3
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    • pp.18-43
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    • 2011
  • The results of study on planting and cultivate of Hong Man-Seon(1643~1715)'s 'Salimkyungjae(The Economy of Forest)' the first summative textbook of agricultural skill of South Korea, are as follows. First, 'Salimkyungjae' suggests that one can enrich oneself, eat fruits in fall, enjoy the shade of trees in summer, and enjoy flowers in spring if one plants tree with 10 year plan with knowledge of ecology. Second, the number of plants had increased continuously from the early Chosun Dynasty to the mid Chosun Dynasty. The 52 plants in the book are classified into 31 trees, 8 shrubs, 3 others, and 10 herbs, and 28 of them are fruit trees. Hence, we can see that the book is for the promotion of welfare. Third, planting(transplantation) is the best on January of the lunar calendar, and the second on February, and fertile soil should be added much. Trees must be planted as deep as once it was planted, and buttressed. It will sprout well if it is planted at the depth of one inch, and planting a cutting should be carried out at the early March with 5 inch and finger-thick branches. Grafting is the best when it begins to sprout. Fruit trees will bear many fruits if they are grafted at the direction of South, and fruits will be greater if the trees' branches are cutting off on January. Especially, January was selected for the best season of planting traditionally. Fourth, flower trees are planted or sowed with manure around January and February of the lunar calendar, and it is recommended to replant them into flowerpots with manure when having flower buds around March and April of the lunar calendar. It would bloom earlier when using water mixed with stable manure, and sulfur smoke can be used in order to change the flower color from red to white. Flowerpots would be placed at half shaded lot with being supported by bricks. Pomegranate, gardenia, camellia and four-season flower should be planted after flowers fallen. When flower trees are beside walls, they need to be rotated frequently since their branches all point toward house. Seeds need to be preserved in a sunny hut, where its entrance and ventilating openings would be at south because it is convenient to manage pots. Fifth, insects hidden at fruit trees would be destroyed by torch smoke when roosters cry on New year's day of the lunar calendar. Insects would be decoyed into straw hanged at dawn of Cheongmyeongday(淸明日). Insects on fruit trees would be controlled using sulfur powder to close up holes or sulfur smoke to fumigate. Particularly, it suggests that utilization of fertile soil would be the best solution for growing health plants and preventing pest.

Real-Time Flight Testing for Developing an Autonomous Indoor Navigation System for a Multi-Rotor Flying Vehicle (실내 자율비행 멀티로터 비행체를 위한 실시간 비행시험 연구)

  • Kim, Hyeon;Lee, Deok Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.4
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    • pp.343-352
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    • 2016
  • A multi-rotor vehicle is an unmanned vehicle consisting of multiple rotors. A multi-rotor vehicle can be categorized as tri-, quad-, hexa-, and octo-rotor depending on the number of the rotors. Multi-rotor vehicles have many advantages due to their agile flight capabilities such as the ability for vertical take-off, landing and hovering. Thus, they can be widely used for various applications including surveillance and monitoring in urban areas. Since multi-rotors are subject to uncertain environments and disturbances, it is required to implement robust attitude stabilization and flight control techniques to compensate for this uncertainty. In this research, an advanced nonlinear control algorithm, i.e. sliding mode control, was implemented. Flight experiments were carried out using an onboard flight control computer and various real-time autonomous attitude adjustments. The feasibility and robustness for flying in uncertain environments were also verified through real-time tests based on disturbances to the multi-rotor vehicle.

Study on the soil related assessment factors in Korean Environmental Impact Assessment (환경영향평가 시 토양 관련 평가 항목에 대한 고찰)

  • Yang, Jihoon;Park, Sun Hwan;Kim, Tae Heum;Hwang, Sang Il
    • Journal of Environmental Impact Assessment
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    • v.25 no.1
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    • pp.41-50
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    • 2016
  • Environmental impact assessment has been implemented for more than 30 years in Korea. During that period, various amendments were carried out about target plan and assessment factors. However, in current environmental impact assessment act, only a few factors has been considered for soil environment assessment. This study analyzes the national and foreign environmental impact assessment guidelines on soil related factors and figures out the problems and implications of Korean environmental impact assessment. In Korea, water quality, topography and geology, hydraulics and hydrology, and soil contamination were analyzed as a soil related factors. The main assessment targets were pollution related factors such as soil pollution levels, amount of rainfall runoff, and non-point sources. However, in the case of foreign guidelines, soil compaction, soil sealing, and soil salinization is being analyzed for evaluating function and quality of soil environment. The revision of soil-related factors are needed for sustainable development of Korea.

Research on the Effect of the Control Methods of Irrigation Water on the Growth and Yield of Paddy Rice. (한발기에 있어서 용수관리 방법이 수도생육과 그 수량에 미치는 영향에 관한 연구)

  • 김시원
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.13 no.1
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    • pp.2177-2190
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    • 1971
  • This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

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Studies on the red-yellow soil in Honam rolling area - Improvement of soil fertility - (호남야산(湖南野山)에 분포(分布)하고 있는 적황색(赤黃色)에 관(關)한 연구(硏究) - 토양비옥도(土壤肥沃度) 증진(增進)에 관(關)하여 -)

  • Chae, Sang Suk;Chang, Young Sun;Lee, Hwa Soo;Hong, Chong Woon
    • Korean Journal of Soil Science and Fertilizer
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    • v.7 no.1
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    • pp.29-34
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    • 1974
  • On a newly reclamed acidic Song-jong soil (soil of a member of fine loamy, mesic family of Hapludults) an experiment was carried out to find out the proper measure of the improvement of soil fertility with soybean as test crop. Results are summarized as follow: 1. Application of compost (1 ton/10a), lime (lime requirement)and fused phosphate (equivalent to 5% of the phosphate fixation coefficient)resulted in the increase of soybean yield by 93.3% over the check plot (N: 6kg/10a, $P_2O_5$: 9kg/10a, $K_2O$: 6kg/10a). The application of fused phosphate at the level of 5% of phosphate fixation coefficient N (6kg/10a) and K(6kg/10a) brought the yield increase by 62.7% over the check plot. However, although the pH of the soil was adjusted to 7.0 by liming, the application of lime with moderate dose of phosphate ($P_2O_5$: 9kg/10a) did not increase the yield of soybean significantly. And the application of fused phosphate at the level of 5% of phosphate fixation coefficient increased the available soil P from 14 ppm to around 100 ppm as tested after harvest. 2. Application of compost (1 ton/10a) increased the organic matter content of soil by 0.8% when tested after harvest. While, the application of rice straw (0.5 ton/10a) did not alter the soil organic matter content. The CEC of the soil tested after havest found incereased significantly by the addition of lime and compost. 3. Plant analysis revealed that the $K_2O/Ca+Mg$ is better correlated with the yield than the absolute concentration of $K_2O$ in plant tissue. Between the concentration of $P_2O_5$ in plant tissue and the yield of soybean, a typical C-curve relationship was observed, indicating that in this particular soil, phosphate was the primary growth liming factor.

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