• 제목/요약/키워드: extremes

검색결과 244건 처리시간 0.026초

Extreme point results for robust schur stability

  • Kang, Hwan-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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    • pp.467-470
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    • 1994
  • In this paper, we develop two sufficient conditions for Schur stability of convex combinations of discrete time polynomials. We give conditions under which Schur stability of the extremes implies Schur stability of the entire convex combination. These results are based on Bhattacharyya's result(1991), the AHMC theory in Barmish and Kang's paper (1993) and the bilinear transformation. Important applications of the results involves robust Schur stability of a feedback system having degenerate interval plants in an extreme point context.

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Life of the Milky Way Galaxy

  • 안덕근
    • 천문학회보
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    • 제37권1호
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    • pp.31.1-31.1
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    • 2012
  • I will report recent progress in understanding properties of stellar and interstellar components of the Milky Way Galaxy on the two extremes - ongoing star formation activities in the Galactic center and stellar relics in the halo. Properties of the interstellar medium in the Galactic center and their relationship with star formation activities will be discussed based on by far the largest mid-IR spectroscopic data set in this region. Correlations between stellar kinematics and metallicities in the halo will be presented, along with a discussion on the estimation of fundamental stellar parameters from a set of empirically calibrated isochrones.

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CONVERGENCE RATE OF EXTREMES FOR THE GENERALIZED SHORT-TAILED SYMMETRIC DISTRIBUTION

  • Lin, Fuming;Peng, Zuoxiang;Yu, Kaizhi
    • 대한수학회보
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    • 제53권5호
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    • pp.1549-1566
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    • 2016
  • Denote $M_n$ the maximum of n independent and identically distributed variables from the generalized short-tailed symmetric distribution. This paper shows the pointwise convergence rate of the distribution of $M_n$ to exp($\exp(-e^{-x})$) and the supremum-metric-based convergence rate as well.

Evolution of Agrometeorology at the Global Level

  • Sivakumar, M.V.K.
    • 한국농림기상학회:학술대회논문집
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    • 한국농림기상학회 2003년도 춘계 학술발표논문집
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    • pp.161-178
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    • 2003
  • Agriculture is probably the most weather-dependent of all human activities. Variations lil climate have been, and continue to be, the principal source of fluctuations in global food production, particularly in the semi-arid tropical countries of the developing world. Throughout history, extremes of heat and cold, droughts and floods, and various forms of violent weather have wreaked havoc on the agricultural systems that depend on for food.(omitted)

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Outbreaks of Yuzu Dieback in Goheung Area: Possible Causes Deduced from Weather Extremes

  • Kim, Kwang-Hyung;Kim, Gyoung Hee;Son, Kyeong In;Koh, Young Jin
    • The Plant Pathology Journal
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    • 제31권3호
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    • pp.290-298
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    • 2015
  • Starting in 2012, severe diebacks usually accompanied by abundant gum exudation have occurred on yuzu trees in Goheung-gun, Jeonnam Province, where severely affected trees were occasionally killed. On-farm surveys were conducted at 30 randomly-selected orchards located at Pungyang-myeon, Goheung-gun, and the resulting disease incidences were 18.5% and 39.6% for dieback and gumming symptoms, respectively. Black spots on branches and leaves also appeared on infected trees showing a typical dieback symptom. Morphological and molecular identifications of the isolated fungal organisms from lesions on the symptomatic leaves and branches revealed that they are identical to Phomopsis citri, known to cause gummosis. In order to find the reason for this sudden epidemic, we investigated the weather conditions that are exclusively distinct from previous years, hypothesizing that certain weather extremes might have caused the severe induction of pre-existing disease for yuzu. There were two extreme temperature drops beyond the yuzu's cold hardiness limit right after an abnormally-warm-temperature-rise during the winter of 2011-12, which could cause severe frost damage resulting in mechanical injuries and physiological weakness to the affected trees. Furthermore, there was an increased frequency of strong wind events, seven times in 2012 compared to only a few times in the previous years, that could also lead to extensive injuries on branches. In conclusion, we estimated that the possible damages by severe frost and frequent strong wind events during 2012 could cause the yuzu trees to be vulnerable to subsequent fungal infection by providing physical entries and increasing plant susceptibility to infections.

중증 근무력증과 전신성 홍반성 낭창의 동반 발생 (Coexistence of Myasthenia Gravis and Systemic Lupus Erythematosus)

  • 허재혁;민주홍;조중양;김남희;이광우
    • Annals of Clinical Neurophysiology
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    • 제7권2호
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    • pp.93-96
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    • 2005
  • Background: Myasthenia gravis (MG) and systemic lupus erythematosus (SLE) are well recognized to coexist and have some similarities in immunologic, clinical and serologic findings. Despite several reports of the association with autoantibodies and thymectomy in these disorders, the pathomechanism of coexistence remains to be elucidated. Objective: We aimed to investigate the relationship of MG and SLE through overall features of patients with both disorders;: clinical, laboratory, and electrophysiological findings. Materials and Methods: We reviewed the medical records of 6 consecutive patients with MG and SLE (2 men, 4 women, ages 17-51, mean 30.5 years, Seoul National University Hospital, from 1998 to 2005). Results: Three patients who developed SLE first, had ocular type of MG and 2 were children showing much severe and recurrent SLE features and only 1 patient had thymic hyperplasia. The other 3 developed MG first and they were generalized type and none underwent thymectomy. In addition, the development of MG or SLE was not coincident with remission or improvement of another disorder. Conclusion: The coexistence of SLE and MG may support the hypothesis of two different antibody populations modulated by thymus in the opposite extremesThis report suggests that the systemic and extensive autoimmune response in preceding MG or SLE may effect the development of the other disorder followed, while. the coexistence of two disorders cannot be explained by the hypothesis of two different antibody populations modulated by thymus in the opposite extremes The role of thymectomy and the theorectical subsequent effect on the development of SLE have been debated with controversy. However, SLE occurred without thymectomy in MG and these disorders did not develop in the quiescent period of another disorder. Therefore, the other pathomechanism for the coexistence of MG and SLE should be elucidated.

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Thermal and light impacts on the early growth stages of the kelp Saccharina angustissima (Laminariales, Phaeophyceae)

  • Augyte, Simona;Yarish, Charles;Neefus, Christopher D.
    • ALGAE
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    • 제34권2호
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    • pp.153-162
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    • 2019
  • Anthropogenic disturbances, including coastal habitat modification and climate change are threatening the stability of kelp beds, one of the most diverse and productive marine ecosystems. To test the effect of temperature and irradiance on the microscopic gametophyte and juvenile sporophyte stages of the rare kelp, Saccharina angustissima, from Casco Bay, Maine, USA, we carried out two sets of experiments using a temperature gradient table. The first set of experiments combined temperatures between $7-18^{\circ}C$ with irradiance at 20, 40, and $80{\mu}mol\;photons\;m^{-2}\;s^{-1}$. The second set combined temperatures of $3-13^{\circ}C$ with irradiance of 10, 100, and $200{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Over two separate 4-week trials, in 2014 and again in 2015, we monitored gametogenesis, the early growth stages of the gametophytes, and early sporophyte development of this kelp. Gametophytes grew best at temperatures of $8-13^{\circ}C$ at the lowest irradiance of $10-{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Light had a significant effect on both male and female gametophyte growth only at the higher temperatures. Temperatures of $8-15^{\circ}C$ and irradiance levels of $10-100{\mu}mol\;photons\;m^{-2}\;s^{-1}$ were conditions for the highest sporophyte growth. Sporophyte and male gametophyte growth was reduced at both temperature extremes-the hottest and coldest temperatures tested. S. angustissima is a unique kelp species known only from a very narrow geographic region along the coast of Maine, USA. The coupling of global warming with high light intensity effects might pose stress on the early life-history stages of this kelp, although, as an intertidal species, it could also be better adapted to temperature and light extremes than its subtidal counterpart, Saccharina latissima.

주자의 존양성찰론(存養省察論) (The theory of cunyang and xingcha in Zhuxi's philosophy)

  • 이상돈
    • 한국철학논집
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    • 제38호
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    • pp.39-62
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    • 2013
  • 주자는 중화신설의 확립을 통해 혼연(渾然)한 전체(全體)의 미발(未發)과 찬연(粲然)한 조리(條理)의 발출(發出)의 이발(已發)이라는 미발이발의 구도를 정립하고 이에 따라 존양성찰(存養省察)이라는 공부론의 핵심을 수립한다. 존양과 성찰은 미발공부와 이발공부인데 심(心)의 동정(動靜)으로 구별된 공부 방법이라는 점에서 정시(靜時)공부와 동시(動時)공부로 규정된다. 또한 존양은 미발에서는 본체가 혼연이 존재하므로 그것을 온전히 보전하는 전체(全體)라는 특징을 가지며, 이발에서는 조리가 발동하는 시점이고 지점이므로 그것을 살피는 심기(審幾)라는 특징을 보인다. 이는 "중용"에서는 치중(致中)과 치화(致和)로 표현된다. 여기서 미발의 전체와 치중은 결국 천리를 보존하는 의미이며, 이발의 심기와 치화는 결국 인욕을 막는 의미이다. 즉 존천리(存天理)와 알인욕(?人欲)은 존양과 성찰의 실질적 내용이 된다. 한편 엄약사(儼若思)와 무자기(毋自欺)는 각각 "예기"와 "대학"에 근거한 미발공부와 이발공부의 구체적인 방법이라 할 수 있으며, 계신공구(戒愼恐懼)와 성의(誠意) 신독(愼獨)은 "대학"과 "중용"에서 제시된 미발공부와 이발공부의 방법이라 할 수 있다.

New Zealand Hydrology: Key Issues and Research Directions

  • Davie, T.J.A.
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2007년도 학술발표회 논문집
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    • pp.1-7
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    • 2007
  • New Zealand is a hydrologically diverse and active country. This paper presents an overview of the major hydrological issues and problems facing New Zealand and provides examples of some the research being undertaken to solve the problems. Fundamental to any environmental decision making is the provision of good quality hydrometric data. Reduced funding for the national hydrometric network has meant a reduction in the number of monitoring sites, the decision on how to redesign the network was made using information on geographic coverage and importance of each site. New Zealand faces a major problem in understanding the impacts of rapid land use change on water quantity and quality. On top of the land use change is overlain the issue of agricultural intensification. The transfer of knowledge about impacts of change at the small watershed scale to much larger, more complex watersheds is one that is attracting considerable research attention. There is a large amount of research currently being undertaken to understand the processes of water and nutrient movement through the vadose zone into groundwater and therefore understanding the time taken for leached nutrients to reach receiving water bodies. The largest water management issue of the past 5 years has been based around fair and equitable water allocation when there is increasing demand for irrigation water. Apart from policy research into market trading for water there has been research into water storage and transfer options and improving irrigation efficiency. The final water management issue discussed concerns the impacts of hydrological extremes (floods and droughts). This is of particular concern with predictions of climate change for New Zealand suggesting increased hydrological extremes. Research work has concentrated on producing predictive models. These have been both detailed inundation models using high quality LIDAR data and also flood models for the whole country based on a newly interpolated grid network of rainfall.

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