• Polymer(Korea)
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• v.33 no.2
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• pp.144-152
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• 2009

The thermal and optical properties of poly {1-(cholesteryloxycarbonylalkanoyloxy) ethylene}s (PCALEn, n=2$\sim$8,10, the number of methylene units in the spacer) were investigated. All of the homologues formed monotropic cholesteric phases with left-handed helical structures. PCALEn with n=2 or 10, in constrast with PCALEn with $3{\leq}n{\leq}8$, did not display reflection colors over the full cholesteric range, suggesting that the helical twisting power of the cholesteryl group highly depends on the length of the spacer connecting the cholesteryl group to the polyethylene chain. The glass transition temperatures decreased with increasing n. The isotropic-cholesteric phase transition temperatures decreased with increasing n up to 7 and showed an odd-even effect. However it became almost constant when n is more than 7. This behavior is rationalized in terms of the change in the average shape of the side chain on varing the parity of the spacer. This rationalization also accounts for the observed variation of the entropy gain for the clearing transition. The thermal stability and degree of order in the mesophase and the temperature dependence of the optical pitch observed for PCALEn were significantly different from those reported for cellulose tri(cholesteryloxycarbonyl)alkanoates. The results were discussed in terms of the differences in the chemical structure and flexibility of main chain and the number of the mesogenic units per repeating unit.

• English & American cultural studies
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• v.10 no.2
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• pp.73-97
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• 2010

Representation of destitution may be considered as an expression of a social desire toward forging a bond or solidarity with the impoverished. However, political and ethical demands of the solidarity force the formulaic framework structuring the form of representation to its limits. The thesis aims to examine the responses to such demands within the tradition of modernist literature that can be traced from Charles Baudelaire, Knut Hamsun to Franz Kafka and that somehow culminates with Samuel Beckett, and to analyze how the issue of destitution that weaves through Beckett's works criticizes and inherits such a heritage. Whereas destitution in 19th century Realism is structurally fixed and its potential for change is inherently excluded, for these writers, destitution is no longer the state of rigid reality in which any possibility is limited. It is destitution as an imperative that calls for exploitation of possibilities that can be recuperated from the impoverished condition of destitution. What these writers consistently resist against is destitution that leads to compensation and reward. Since occupying a superior position toward the other as the subject of description or sympathy can be seen as one form of profit or reward, they have persistently pursued absolute solitariness and austere conditions rather than prematurely simulating a sense of solidarity and community. The ultimate goal of destitution as an imperative is to pursue destitution in order to worsen it by identifying and then excluding and expending possessions and assets to a state of penury. This is a paradoxical process that opens up the realm of possibilities of destitution and redefines it as abundance and wealth. Destitution for Beckett as seen in the writers above is the objective of literature. But, what he focuses on is to amplify the shreds of economic world that still remain in a state of poverty and to reveal extreme poverty as a state of odd affluence and to transform it into a pursuit of accumulation and profit. One of his famous axioms, "less is more", contains the essence of such a paradoxical strategy. In a sense, such approach is a twist on the strategy that identifies and uses any remaining potential hidden in destitution as was pursued by other writers. It also expands on the imagination of the destitute described by Hamsun. But Hamsun and Beckett are diametrical opposites. Unlike Hamsun, Beckett does not link imagination with a sense of guilt. Imagination is not intended to overcome the destitute reality nor to culminate in artistic martyrdom as in the case of Kafka's hunger artist. The imagination of the impoverished in Beckett is simply a hilarious game and not an escape that ends in a sense of guilt. This game formulates a "rhetorical question" or derision at the ironical situation where the pursuit of hunger and art as the disinterestedness has been turned into symbolic capital. It is inherently a fundamental critique at the aestheticization of destitution that has been pursued by Modernism. Beckett's efforts at divulging falsehood inherent in non-profit acts such as charity, donation and hospitality are dissections of social fictions in which aestheticization of destitution remains a part of the whole.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.455-462
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• 2016

Pseudomonas aeruginosa P-5 is an unusual organism capable of synthesizing polyhydroxyalkanoates (PHAs) consisting of 3-hydroxyvalerate (3HV) and medium-chain-length (MCL) 3-hydroxyalkanoate (3HA) monomer units when C-odd alkanoic acids are fed as the sole carbon source. Evaluation of the substrate chain-length specificity of two P. aeruginosa P-5 PHA synthases ($PhaC1_{P-5}$ and $PhaC2_{P-5}$) by heterologous expression of $PhaC1_{P-5}$ and $PhaC2_{P-5}$ genes in Pseudomonas putida GPp104 revealed that $PhaC2_{P-5}$ incorporates both 3HV and MCL 3HAs into PHA, whereas $PhaC1_{P-5}$ favors only MCL 3HAs for polymerization. In order to obtain $PhaC2_{P-5}$ mutants with altered substrate specificity, site-specific mutagenesis for $PhaC2_{P-5}$ was conducted. Amino acid substitutions of $PhaC2_{P-5}$ at two positions (Ser326Thr and Gln482Lys) were very effective for synthesizing copolymers with a higher 3HV fraction. When recombinant P. putida GPp104 harboring double mutated $phaC2_{P-5}$ gene ($phaC2_{P-5}QKST$) was grown on nonanoic acid, 2.5-fold increase of copolymer content with 3.8-fold increase of 3HV fraction was observed. The $phaC2_{P-5}QKST$-containing Ralstonia eutropha PHB-4 supplemented with valeric acid also produced copolymers consisting of 3HV and 3-hydroxyheptanoate with a high 3HV fraction. These results suggest that recombinants containing $phaC2_{P-5}QKST$ could be useful for production of new PHA copolymers with improved material properties.

• Journal of Korean Society of Forest Science
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• v.6 no.1
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• pp.27-31
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• 1967

The bamboo is a plant whose culm grows straight up. This growing characteristics has been widely utilized in industry and craft. But the developments of handcraft making and horticultural techniques in recent years become to demand the bent bamboo culms. This study has been conducted at the experimental grove located at Hyunnae Ri, Okkye Myun, Myungju Gun, Kangwon Do since 1960. Although it has been known that the secret for which bamboo shoots complet growth within 40 odd days lies in their rhizomes, this writer felt the bamboo culm sheath might be another factor in addition. Hence some were stripped of sheath in this bending study as the following: 1. Time of sheath stripping. 2. Direction of sheath stripped for arbitrary bending. 3. Accuracy of bending following the size (growth) of bamboo shoots. The following results were obtained: 1. Bamboo shoots begin to appear in April. But the bamboo shot up in June showed the best bending result with 68% of bending efficiency. 2. Bending of the culm was facilitated by stripping off the sheath located on the side of the direction toward which bending was desired. By doing this, the culm could be bent as much as 90 degrees. But the culm totally stripped of sheath could be bent in any direction. 3. In order to determine the accuracy of bending of bamboo shoots growing, sheath were stripped off the shoots of which height ranged from 10 centimeter to 150 centimeters. The shoots with height of 110 centimeters showed the best result with 90%.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.127-146
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• 2017

Services using artificial intelligence have begun to emerge in daily life. Artificial intelligence is applied to products in consumer electronics and communications such as artificial intelligence refrigerators and speakers. In the financial sector, using Kensho's artificial intelligence technology, the process of the stock trading system in Goldman Sachs was improved. For example, two stock traders could handle the work of 600 stock traders and the analytical work for 15 people for 4weeks could be processed in 5 minutes. Especially, big data analysis through machine learning among artificial intelligence fields is actively applied throughout the financial industry. The stock market analysis and investment modeling through machine learning theory are also actively studied. The limits of linearity problem existing in financial time series studies are overcome by using machine learning theory such as artificial intelligence prediction model. The study of quantitative financial data based on the past stock market-related numerical data is widely performed using artificial intelligence to forecast future movements of stock price or indices. Various other studies have been conducted to predict the future direction of the market or the stock price of companies by learning based on a large amount of text data such as various news and comments related to the stock market. Investing on commodity asset, one of alternative assets, is usually used for enhancing the stability and safety of traditional stock and bond asset portfolio. There are relatively few researches on the investment model about commodity asset than mainstream assets like equity and bond. Recently machine learning techniques are widely applied on financial world, especially on stock and bond investment model and it makes better trading model on this field and makes the change on the whole financial area. In this study we made investment model using Support Vector Machine among the machine learning models. There are some researches on commodity asset focusing on the price prediction of the specific commodity but it is hard to find the researches about investment model of commodity as asset allocation using machine learning model. We propose a method of forecasting four major commodity indices, portfolio made of commodity futures, and individual commodity futures, using SVM model. The four major commodity indices are Goldman Sachs Commodity Index(GSCI), Dow Jones UBS Commodity Index(DJUI), Thomson Reuters/Core Commodity CRB Index(TRCI), and Rogers International Commodity Index(RI). We selected each two individual futures among three sectors as energy, agriculture, and metals that are actively traded on CME market and have enough liquidity. They are Crude Oil, Natural Gas, Corn, Wheat, Gold and Silver Futures. We made the equally weighted portfolio with six commodity futures for comparing with other commodity indices. We set the 19 macroeconomic indicators including stock market indices, exports & imports trade data, labor market data, and composite leading indicators as the input data of the model because commodity asset is very closely related with the macroeconomic activities. They are 14 US economic indicators, two Chinese economic indicators and two Korean economic indicators. Data period is from January 1990 to May 2017. We set the former 195 monthly data as training data and the latter 125 monthly data as test data. In this study, we verified that the performance of the equally weighted commodity futures portfolio rebalanced by the SVM model is better than that of other commodity indices. The prediction accuracy of the model for the commodity indices does not exceed 50% regardless of the SVM kernel function. On the other hand, the prediction accuracy of equally weighted commodity futures portfolio is 53%. The prediction accuracy of the individual commodity futures model is better than that of commodity indices model especially in agriculture and metal sectors. The individual commodity futures portfolio excluding the energy sector has outperformed the three sectors covered by individual commodity futures portfolio. In order to verify the validity of the model, it is judged that the analysis results should be similar despite variations in data period. So we also examined the odd numbered year data as training data and the even numbered year data as test data and we confirmed that the analysis results are similar. As a result, when we allocate commodity assets to traditional portfolio composed of stock, bond, and cash, we can get more effective investment performance not by investing commodity indices but by investing commodity futures. Especially we can get better performance by rebalanced commodity futures portfolio designed by SVM model.