• Title/Summary/Keyword: hypothesis-generating

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Simple hypotheses testing for the number of trees in a random forest

  • Park, Cheol-Yong
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.2
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    • pp.371-377
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    • 2010
  • In this study, we propose two informal hypothesis tests which may be useful in determining the number of trees in a random forest for use in classification. The first test declares that a case is 'easy' if the hypothesis of the equality of probabilities of two most popular classes is rejected. The second test declares that a case is 'hard' if the hypothesis that the relative difference or the margin of victory between the probabilities of two most popular classes is greater than or equal to some small number, say 0.05, is rejected. We propose to continue generating trees until all (or all but a small fraction) of the training cases are declared easy or hard. The advantage of combining the second test along with the first test is that the number of trees required to stop becomes much smaller than the first test only, where all (or all but a small fraction) of the training cases should be declared easy.

Another Evidence for Nitric Oxide as Mediator of Relaxation of Isolated Rabbit and Human Corpus Cavernosum

  • Chang, Ki-Churl
    • Biomolecules & Therapeutics
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    • v.2 no.2
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    • pp.136-140
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    • 1994
  • To prove the hypothesis that NO- and N $O_2$-carrying molecules potentiate photorelaxation by generating NO, investigation was carried out using isolated rabbit and human corpus cavernosum. Corporal smooth muscle, in the presence or absence of endothelium, relaxed only slightly upon ultraviolet light (366 nm) irradiation. But, NO-and/or N $O_2$-containing compounds such as streptozotocin and $N^{G}$-nitro-L-arginine methyl ester significantly (p<0.01) enhanced photorelaxation in this tissue. In addition, $N^{G}$-nitro-D-arginine methyl ester, known to lack inhibitory action on NO synthase, showed concentration-dependent potentiation of the photorelaxation. Oxygen radical generating system via copper+ascorbic acid and guanylate cyclase inhibitor, methylene blue, significantly (p<0.05) inhibited the streptozotocin-potentiated photorelaxation. Nitrite was accumulated by photolysis of streptozotocin, $N^{G}$-nitro-L-arginine methyl ester and $N^{G}$-nitro-D-arginine methyl ester, in a concentration and exposure time dependent manner. These observations indicate that NO is a potent relaxant of rabbit and human corpus cavernosum and further support the hypothesis that NO is released by photolysis from NO- and N $O_2$-carrying molecules.lecules.

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The Features of the Hypotheses Generated by Pre-service Elementary Teachers Using the Form of Peirce's Abduction (Peirce의 귀추법 양식을 이용한 교육 대학생들이 생성한 가설의 특징 분석)

  • Joung Yong-Jae;Song Jin-Woong
    • Journal of Korean Elementary Science Education
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    • v.25 no.2
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    • pp.126-140
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    • 2006
  • The purpose of this study was to design a 'Form of Abduction' which is the 'guide form used in generating hypothesis through abduction', and to analyze the features of the hypotheses generated with the 'Form of Abduction' compared with those generated without any special guide form. Through a review of Peirce's literature regarding the meaning and frame of abduction, a 'Form of Abduction' was designed as a three step format as follows: (i) writing down what is doubted, (ii) wiling tentative explanations which replace what is doubted with what is believed, (iii) writing the tentative explanations as hypotheses. The thirty four pre-service elementary teachers were asked to generate hypotheses without a 'Form of Abduction' at first, and then were asked to do so again using the form. The results of analysing the features of the hypotheses were as follows: in the case of using a 'Form of Abduction', firstly, the types of misunderstanding or mis-adapting the meaning of hypothesis were found to be rare, and secondly, the types of 'giving explanation about the cause of problematic situations through analogical inferencing from the existing knowledge' were found to be double the rate of when no special guide form was used. In conclusion, the hypotheses generated with the 'Form of Abduction' had the features of satisfying the original meaning of hypothesis, i.e. 'explaining the cause of phenomenon and leading to knowledge expansion'. These results also showed that using a 'Form of Abduction', although its form was simple, could be a way of helping students generate hypothesis properly in science classes.

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Generating Premise-Hypothesis-Label Triplet Using Chain-of-Thought and Program-aided Language Models (Chain-of-Thought와 Program-aided Language Models을 이용한 전제-가설-라벨 삼중항 자동 생성)

  • Hee-jin Cho;Changki Lee;Kyoungman Bae
    • Annual Conference on Human and Language Technology
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    • 2023.10a
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    • pp.352-357
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    • 2023
  • 자연어 추론은 두 문장(전제, 가설)간의 관계를 이해하고 추론하여 함의, 모순, 중립 세 가지 범주로 분류하며, 전제-가설-라벨(PHL) 데이터셋을 활용하여 자연어 추론 모델을 학습한다. 그러나, 새로운 도메인에 자연어 추론을 적용할 경우 학습 데이터가 존재하지 않거나 이를 구축하는 데 많은 시간과 자원이 필요하다는 문제가 있다. 본 논문에서는 자연어 추론을 위한 학습 데이터인 전제-가설-라벨 삼중항을 자동 생성하기 위해 [1]에서 제안한 문장 변환 규칙 대신에 거대 언어 모델과 Chain-of-Thought(CoT), Program-aided Language Models(PaL) 등의 프롬프팅(Prompting) 방법을 이용하여 전제-가설-라벨 삼중항을 자동으로 생성하는 방법을 제안한다. 실험 결과, CoT와 PaL 프롬프팅 방법으로 자동 생성된 데이터의 품질이 기존 규칙이나 기본 프롬프팅 방법보다 더 우수하였다.

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Pre-service Primary Teachers' Justification of their Hypotheses about the Brightness of Electric Bulbs (전구의 밝기에 대한 초등 예비교사의 가설 검증 활동)

  • Jang Byung-Ghi
    • Journal of Korean Elementary Science Education
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    • v.24 no.5
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    • pp.518-530
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    • 2005
  • The purpose of this study was to investigate the characteristics of pre-service primary teachers' justifying their hypotheses about the brightness of electric bulbs. They conducted their experiments and wrote their experimental results and ideas on their worksheets. The worksheets for generating and evaluating scientific hypothesis were analyzed. Most of them generated the consumption hypothesis and designed the experiments to confirm their hypotheses or directly measure without the change of experimental conditions. The responses for valid experimental designs were $74\%$ of total responses. The $62\%$ of total responses was valid prediction for experimental results. The $60\%$ of pre-service teachers described the experimental results correctly. But other teachers described the biased results or inappropriate results. The $54\%$ of them refuted hypotheses and the $36\%$ confirmed their hypotheses. The theory-based responses were $51\%$ and the evidence-based responses were $47\%$. The $64\%$ of them proposed the possibility of the alternative hypothesis after testing their hypotheses. This study also discussed the implications of these findings for teaching and Loaming in science education.

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Simulated Annealing Algorithm Using Cauchy-Gaussian Probability Distributions (Cauchy와 Gaussian 확률 분포를 이용한 Simulated Annealing 알고리즘)

  • Lee, Dong-Ju;Lee, Chang-Yong
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.3
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    • pp.130-136
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    • 2010
  • In this study, we propose a new method for generating candidate solutions based on both the Cauchy and the Gaussian probability distributions in order to use the merit of the solutions generated by these distributions. The Cauchy probability distribution has larger probability in the tail region than the Gaussian distribution. Thus, the Cauchy distribution can yield higher probabilities of generating candidate solutions of large-varied variables, which in turn has an advantage of searching wider area of variable space. On the contrary, the Gaussian distribution can yield higher probabilities of generating candidate solutions of small-varied variables, which in turn has an advantage of searching deeply smaller area of variable space. In order to compare and analyze the performance of the proposed method against the conventional method, we carried out experiments using benchmarking problems of real valued functions. From the result of the experiment, we found that the proposed method based on the Cauchy and the Gaussian distributions outperformed the conventional one for most of benchmarking problems, and verified its superiority by the statistical hypothesis test.

An Analysis of the Experimental Designs Suggested by Students for Testing Scientific Hypotheses (과학적 가설 검증을 위한 학생들의 실험 설계 내용 분석)

  • Park, Jong-Won
    • Journal of The Korean Association For Science Education
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    • v.23 no.2
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    • pp.200-213
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    • 2003
  • This study is one of the successive studies for investigating students' processes of generating and evaluating scientific hypothesis. In this study, I analyzed the characteristics of students' experimental design to test whether the given hypotheses were correct or not. As results, it was found that (1) 3 components (experimental method, prediction of the result of experiment, evaluation of hypothesis) were needed to complete description of the experimental design, (2) students tried to test hypothesis considered as being correct as well as hypothesis considered as being false by students, (3) student tried to confirm hypothesis, which was considered as being correct, based on theoretical approach rather than experimental approach, (4) students' experimental design could be classified as two types, that is, direct experimental testing and comparative experimental design, and the latter could be classified as two subtypes; positive comparative one and negative comparative one, (5) students showed tendency to design positive comparative experiment when they considered hypothesis as being correct, and vise versa, (6) students preferred the prediction which could confirm the hypothesis when they considered the hypothesis as being correct, and vise versa, (7) many students rejected contradicting prediction even though they did not actually conduct experiment yet.

Urokinase Inhibitor Design Based on Pharmacophore Model Derived from Diverse Classes of Inhibitors

  • Shui, Liu;Bharatham, Nagakumar;Bharatham, Kavitha;Lee, Keun-Woo
    • Bioinformatics and Biosystems
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    • v.1 no.2
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    • pp.115-122
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    • 2006
  • A three-dimensional pharmacophore model was developed based on 24 currently available inhibitors, which were rationally selected from 472 compounds with diverse molecular structure and bioactivity, for generating pharmacophore of uPA (Urokinase Plasminogen Activator) inhibitors. The best hypothesis (Hypo1) comprised of five features, namely, one positive ionizable group, one hydrogen-bond acceptor group and three hydrophobic aromatic groups. The correlation coefficient, root mean square deviation and cost difference were 0.973, 0.695, and 94.291 respectively, suggesting that a highly predictive pharmacophore model was successfully obtained. The application of the model showed great success in predicting the activities of 251 known uPA inhibitors (test set) with a correlation coefficient of 0.837, and there was also none of the outcome hypotheses that had similar cost difference and RMS deviation (RMSD) with that of the initial hypothesis generated by Cat-Scramble validation test with 95% confidence level. Accordingly, our model should be reliable in identifying structurally diverse compounds with desired biological activity.

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Information Arrival between Price Change and Trading Volume in Crude Palm Oil Futures Market: A Non-linear Approach

  • Go, You-How;Lau, Wee-Yeap
    • The Journal of Asian Finance, Economics and Business
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    • v.3 no.3
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    • pp.79-91
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    • 2016
  • This paper is the first of its kind using a non-linear approach based on cross-correlation function (CCF) to investigate the information arrival hypothesis in crude palm oil (CPO) futures market. Based on daily data from 1986 to 2010, our empirical results reveal that: First, the volume of volatility is not a proxy of information flow. Second, dependence causality running from current return to future volume in conditional variance exhibit an asymmetric pattern of time span with different signs of correlation between price and volume series. This finding indicates the presence of noise traders' hypothesis of price-volume interaction in CPO futures market. Both findings suggest that this futures market is weak-form inefficiency. In terms of investors' behavior, they tend to change their expectations on current return based on errors made in previous trade in generating abnormal volume in the subsequent period. As implied, it is advisable for the investors devise their future trading strategies according to time span and changes of return.

Characteristics of phloem translocation of photoassimilates and herbicides (광합성산물과 제초제의 체관이행 기작)

  • Kim, Song-Mun;Hur, Jang-Hyun;Han, Dae-Sung
    • The Korean Journal of Pesticide Science
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    • v.2 no.1
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    • pp.1-11
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    • 1998
  • The generally accepted idea for carbohydrate translocation in plants is an osmotic pressure flow hypothesis. According to the hypothesis, a high concentration of carbohydrate in the phloem of carbohydrate synthesis regions (source) causes a water influx into the phloem. The generated osmotic potential in the phloem is responsible for long distance carbohydrate transport through the positive hydrostatic pressure. In regions of carbohydrate utilization and storage (sink), translocated carbohydrates are continuously metabolized and compartmentalized, generating a concentration gradient between source and sinks. In this system, carbohydrates load into the phloem (phloem loading) and unload out of the phloem (phloem unloading). Phloem-mobile herbicides that are applied to plants are also translocated from the source to sinks. However, some experimental results reveal that the patterns of phloem translocation between carbohydrates and herbicides are different. The differences are due, in part, to the physico-chemical properties of herbicides and to the absence/presence of specific carrier(s) in the phloem.

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