• Title/Summary/Keyword: extreme value theory

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Characteristics of Molecular Band Energy Structure of Lipid Oxidized Mammalian Red Blood Cell Membrane by Air-based Atmospheric Pressure Dielectric Barrier Discharge Plasma Treatment

  • Lee, Jin Young;Baik, Ku Youn;Kim, Tae Soo;Jin, Gi-Hyeon;Kim, Hyeong Sun;Bae, Jae Hyeok;Lee, Jin Won;Hwang, Seung Hyun;Uhm, Han Sup;Choi, Eun Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.262.1-262.1
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    • 2014
  • Lipid peroxidation induces functional deterioration of cell membrane and induces cell death in extreme cases. These phenomena are known to be related generally to the change of physical properties of lipid membrane such as decreased lipid order or increased water penetration. Even though the electric property of lipid membrane is important, there has been no report about the change of electric properties after lipid peroxidation. Herein, we demonstrate the molecular energy band change in red blood cell membrane through peroxidation by air-based atmospheric pressure DBD plasma treatment. Ion-induced secondary electron emission coefficient (${\gamma}$ value) was measured by using home-made gamma-focused ion beam (${\gamma}$-FIB) system and electron energy band was calculated based on the quantum mechanical Auger neutralization theory. The oxidized lipids showed higher gamma values and lower electron work functions, which implies the change of surface charging or electrical conductance. This result suggests that modified electrical properties should play a role in cell signaling under oxidative stress.

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Threshold estimation for the composite lognormal-GPD models (로그-정규분포와 파레토 합성 분포의 임계점 추정)

  • Kim, Bobae;Noh, Jisuk;Baek, Changryong
    • The Korean Journal of Applied Statistics
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    • v.29 no.5
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    • pp.807-822
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    • 2016
  • The composite lognormal-GPD models (LN-GPD) enjoys both merits from log-normality for the body of distribution and GPD for the thick tailedness of the observation. However, in the estimation perspective, LN-GPD model performs poorly due to numerical instability. Therefore, a two-stage procedure, that estimates threshold first then estimates other parameters later, is a natural method to consider. This paper considers five nonparametric threshold estimation methods widely used in extreme value theory and compares their performance in LN-GPD parameter estimation. A simulation study reveals that simultaneous maximum likelihood estimation performs good in threshold estimation, but very poor in tail index estimation. However, the nonparametric method performs good in tail index estimation, but introduced bias in threshold estimation. Our method is illustrated to the service time of an Israel bank call center and shows that the LN-GPD model fits better than LN or GPD model alone.

Face to Face with the Past: Memorizing the Plague of Athens through the Exhibition (과거와의 대면 : ${\ll}$미르티스${\gg}$ 전시를 통해 기억된 아테네 대 역병)

  • Cho, Eun-Jung
    • The Journal of Art Theory & Practice
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    • no.14
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    • pp.7-32
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    • 2012
  • The exhibition was started in 2010 in the New Acropolis Museum of Athens and embarked a journey since 2011 as a travelling exhibition inside Greece and abroad. The main purpose of the exhibition was to draw attention of the general public to the value of the 'rescue excavation' and of cultural heritage of Greece, by presenting the reconstruction bust of a girl whose skull was found in Kerameikos cemetery of ancient Athens. The new Kerameikos excavation was initiated by the construction of Metropolitan Railway lines in the center of Athens between 1992 to 1998. It revealed a pit of a mass burial where about 150 people were inhumed in a very hasty way without proper funeral rites or offerings. These bodies are identified as the victims of the infamous plague of Athens in the first years of the Peloponnesian War(430-426 BC). The epidemic disease killed almost one third of the city population including Pericles, and brought extreme fear and panic to the Athens society. The traditional funerary rites were totally disrupted, and the social decorum and the morality among the citizens became enfeebled. The plague and the civil war were the decisive factors to end the Golden Age of Democratic Athens. However, the exhibition organizers did not focus on the tragic aspect of this disaster and its casualties. Their main concern was to simplify the scholarly works of archaeological excavation and microchemistry analysis so that the exhibition viewers will easily understand and empathize the living value of the scholarly works of ancient Greek civilization. The centripetal element of the exhibition was the vivid face of an 11 years old ancient girl 'Myrtis', which was carefully reconstructed based on both the scientific data and artistic imagination. Also the set up of the exhibition was structured in order to stimuli cognitive and emotional experience of the visitors who witnessed the rebirth of a vibrant human being from an ancient debris. The museologists' continuous efforts to promote projects of contemporary artists, publications, and school programs related to the exhibition indicate that the ulterior motive of this exhibition is the cultural education of the present and future generation through the intimate experiences of ancient Greek life. Also this is the reason why the various museums that held the travelling exhibition try to make the presentation as a gesture of memorial service for an anonymous Athenian girl who deceased circa 2400 years ago. The pragmatic efforts of Greek scholars and museologists through exhibition show us a way to find a solution to the continuous threat of cultural resources by massive construction projects and land development, and to overcome public indifference to the history and cultural heritage.

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The Effect of Audit Quality on Crash Risk: Focusing on Distribution & Service Companies (감사품질이 주가급락 위험에 미치는 영향: 유통, 서비스 기업을 중심으로)

  • Chae, Soo-Joon;Hwang, Hee-Joong
    • Journal of Distribution Science
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    • v.15 no.8
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    • pp.47-54
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    • 2017
  • Purpose - According to agency theory, managers have incentives to adjust firm revenues to meet earnings expectations or delay bad news disclosure because of performance-based compensation and their reputation in the market. When the bad news accumulates, stock prices fail to reflect all available information. Thus, market prices of stocks are higher than their intrinsic value. After all, bad news crosses the tipping point, it comes out all at once. That results in stock crashes. Auditors can decrease stock crash risk by reducing agency costs through their informational role. Especially, stock price crash risk is expected to be lower for firms adopting high-quality audits. We focus on distribution and service industry to examine the relation between audit quality and stock price crash risk. Industry specialization and auditor size are used as proxies for auditor quality. Research design, data and methodology - Our sample contains distribution and service industry firms listed in KOSPI and KOSDAQ during a period of 2004-2011. We use a logistic regression to test whether auditor quality influences crash risk. Auditor quality was measured by industry specialist auditor and Big4 / non-Big4 dichotomy. Following the approach in prior researches, we use firm-specific weekly returns to measure crash risk. Firms experiencing at least one stock price crash in a specific week during year are classified as the high risk group. Results - The result of analyzing 429 companies in distribution and service industry is summarized as follows: Above all, it is shown that higher audit quality has a significant negative(-) effect on the crash risk. Crash risk is alleviated for firms audited by industry specialist auditors and Big 4 audit firms. Therefore, our results show that hypotheses are supported. Conclusions - This study is very meaningful as the first study which investigated the effects of high audit quality on stock price crash risk. We provide evidence that high-quality auditors reduce stock price crash risk. Our finding implies that the risk of extreme losses can be reduced through screening of high-quality auditors. Therefore investors and regulators may utilize our findings in their investment and rule making decisions.

Belle Epoque and Dadaism in the Modern Culture (벨 에포크와 다다이즘 - 근대문화의 총체와 해체)

  • Lee, Byung Soo
    • Cross-Cultural Studies
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    • v.33
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    • pp.171-192
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    • 2013
  • The article is a research about the Belle Epoque era and Dadaism in the modern culture as a whole and separate. The years from 1890s to 1914, is known as the Belle Epoque era, in which the European continent including France had developed the climax of the modern culture after the Renaissance. At the same time, it was the period where the postmodern developments were being spread, leading to the present days. Moreover, the main ideologies in art that led to the cultural advancement of the time were impressionism, cubism, art nouveau, evolutionized painting category, symbolism and futurism. It was a literature category that was maintained to present Dadaism and surrealism. Dadaism began since the magazine, Bulletin Dada was published, originating in 1916 by Tristan Tzara of Zurich, Switzerland during the WWI. The extreme motto that the Dadaists supported was a contradiction, as they had to dissolve from their own art movements and expression techniques. However, until Andre Breton introduced 'Manifeste du Surrealisme' in 1924, the "Dada group" had a tremendous influence in France as an epicenter and rejected the modern cause and art that continued during the time, thus attempting its dissolution. First, they rejected the ideology, ethics and customs of rationalism from the previous system and demonstrate an anarchical and anti-bourgeoisie characteristic. They also reject the French lucid thoughts and the artistic techniques. They strongly emphasized on their motto "The idea is created from the mouth", while reframing from the philosophical ideology and at the same time, attempting to express the psychical unconsciousness. Second, the most important catchphrase that the Dadaists supported was the theory of negation. The question "Why do you write?" connotes the negative consciousness about the artistic value and the stereotyped method of the preexisting writing and drawing. Third, the Dadaists bring forward a radical query about all of the former esthetic and morals, and reveal an admirable resistance spirit. They emphasized on the slogan "Dada, means nothing" and insist on 'the anti-literal Dada, anti-artistic Dada, anti-musical Dada'. The Dadaist movement manifested their resistant spirit and the new artistic spirit through the publication of , , and most importantly through the magazine . Fourth, the Dadaists embodied the volume, density, and quality into an image through the auto-technical, cubistic writings and drawings. They ignored the fixed form of arrangements, verses, and rhymes of a poetic diction. The Dadaists utilized an unfamiliar and inversed expression method of applying the combination of the size of print, or capital letters and lowercase letters, even combining printed and handwritten writings. As presented, the auto-technical and cubistic characteristic of expressing the auto-psychical ideology into writing is called as the radical aesthetic and moral and can be considered as the most essential cause of the Dadaists' avant-garde features. As a conclusion, Dadaism demonstrated dual characteristics of consuming the nutritive elements of the modern culture through the most powerful resistance and liberation of the artistic movement of the Belle Epoque era, where at the same time, it deconstructed the modern art. By revolting against the former grounds and expression techniques, and dominating the era with the new artistic spirit, their resistant actions were artistic movements that symbolized the dissolution of the modern times. Moreover, the Dada's expressionism and resistance of saying "There's nothing" can be evaluated as postmodernity's initiative of outweighing the modern history and opening the door for new period of nowadays.

Removal of Red Tide Organisms -1. flocculation of Red Tide Organisms by Using IOSP- (적조생물의 구제 -1. IOSP에 의한 적조생물의 응집제거-)

  • KIM Sung-Jae;CHO Kyu-Dae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.5
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    • pp.448-454
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    • 2000
  • This study was to examine the physicochemical characteristics of coagulation reaction between ignited oyster shell powder (IOSP) and red tide organisms (RTO), and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea,IOSP was made from oyster shell and its physicochemical characteristics were examined for particle size distribution, surface characteristic by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various c(Incentrations of IOSP, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number, IOSP showed positive zeta potentials of $11.1{\~}50.1\;mV\;at\;pH\;6.2{\~}12.7$, A positive zeta potential of IOSP slowly decreased with decreasing pNa 4,0 to 2,0. When pNa reached zero, the zeta potential approached zero, When a pMg value was decreased, the positive zeta potential of IOSP increased until pMg 3.0 and decreased below pMg 3.0. IOSP showed 4.8 mV of positive zeta potential while RTO showed -9.2 mV of negative zeta potential in sea water. A positive-negative EDL (electrical double-layer) interaction occurred between $Mg(OH)_2$ adsorption layer of IOSP and RTO in sea water so that EDL attractive force always worked between them. Hence, their coagulation reaction occurred at primary minimum on which an extreme attractive force acted because of charge neutralization by $Mg(OH)_2$ adsorption layer of IOSP. As a result, the coagulation reaction was rapidly processed and was irreversible according to DLVO (Deriaguin-Landau-Verwey-Overbeek) theory. Removal rates of RTO were exponentially increased with increasing both IOSP concentration and G-value. The removal rates were steeply increased until 50 mg/l of IOSP and reached $100{\%}\;at\;400\;mg/l$ of IOSP. Removal rates of RTO were $70.5,\;70.5,\;81.7,\;85.3{\%}$ for G-values of $1,\;6,\;29,\;139\;sec^(-1)$at IOSP 100 mg/l, respectively. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction.

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