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Development of Applied Music Education Program for Creative and Convergent Thinking-With a Focus on the Capstone design Class (창의·융합적 사고를 위한 실용음악 교육프로그램 개발-캡스톤디자인 수업을 중심으로)

  • Yun, Sung-Hyo;Han, Kyung-hoon
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.4
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    • pp.285-294
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    • 2024
  • This study aims to enhance learners' creative and integrative thinking through the use of a practical music education program, facilitating high-quality artistic activities and the integration of various disciplines. To achieve this, a practical music education program incorporating the PDIE model was designed, and the content validity of the developed program was verified. Through this process, We have researched and described methodologies for multidisciplinary research that can be applied in practical music education. This paper focuses on the fourth session of the study, which deals with the creative and integrative education of practical music and mathematics. The mathematical theory of interest in this research is the Fibonacci sequence, fundamental to the golden ratio in art. The goal is to enable balanced and high-quality creative activities through learning and applying the Fibonacci sequence. Additionally, to verify the validity and effectiveness of the instructional plan, including the one used in the 15-week course, we have detailed the participants involved in the content validation, the procedures of the research, the research tools used, and the methods for collecting and analyzing various data. Through this, We have confirmed the potential of creative and integrative education in higher practical music education and sought to develop educational methodologies for cultivating various creative talents in subsequent research.

The Effect of Regional Differential Electricity Rate System using LMP (Locational Marginal Price) (LMP(Locational Marginal Price) 방식에 의한 지역별 차등 전기요금 제도의 효율성 분석)

  • Jaedo Song
    • Environmental and Resource Economics Review
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    • v.33 no.3
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    • pp.203-239
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    • 2024
  • The introduction of a regional differential electricity rate system is being discussed, and the LMP (Locational Marginal Price) method is mentioned as a promising alternative. Under this background, this study analyzed a mathematical model and suggests that the LMP method produces results that maximize social welfare. The analysis was conducted separately for long-term decision-making where transmission capacity can be expanded, and for short-term decision-making in which transmission capacity is given. The analysis for short-term decision-making was conducted for peak load situations where capacity is insufficient and for non-load situations with spare capacity. The results of the analysis suggested that the price to maximize social welfare is equal to the marginal power generation cost by region, and the difference in marginal cost by region reflects the value lost due to transmission loss and compensation for transmission network investment. In addition, if the transmission capacity is less than the optimal capacity, the compensation for transmission network investment exceeds the incremental cost, providing an incentive to invest in the transmission network. If the transmission capacity exceeds the optimal capacity, the compensation for transmission network investment becomes lower than incremental cost or zero and the investment is not recovered, suppressing the investment in transmission networks. The results are the same as the LMP method suggests, and this means that this method maximizes social welfare and provides an optimal transmission network investment signal. The above analysis results contribute to understanding the characteristics of LMP. In addition, this study discussed what changes are needed in the electricity market when introducing the LMP concept.

The Effect of Price Promotional Information about Brand on Consumer's Quality Perception: Conditioning on Pretrial Brand (품패개격촉소신식대소비자질량인지적영향(品牌价格促销信息对消费者质量认知的影响))

  • Lee, Min-Hoon;Lim, Hang-Seop
    • Journal of Global Scholars of Marketing Science
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    • v.19 no.3
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    • pp.17-27
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    • 2009
  • Price promotion typically reduces the price for a given quantity or increases the quantity available at the same price, thereby enhancing value and creating an economic incentive to purchase. It often is used to encourage product or service trial among nonusers of products or services. Thus, it is important to understand the effects of price promotions on quality perception made by consumer who do not have prior experience with the promoted brand. However, if consumers associate a price promotion itself with inferior brand quality, the promotion may not achieve the sales increase the economic incentives otherwise might have produced. More specifically, low qualitative perception through price promotion will undercut the economic and psychological incentives and reduce the likelihood of purchase. Thus, it is important for marketers to understand how price promotional informations about a brand have impact on consumer's unfavorable quality perception of the brand. Previous literatures on the effects of price promotions on quality perception reveal inconsistent explanations. Some focused on the unfavorable effect of price promotion on consumer's perception. But others showed that price promotions didn't raise unfavorable perception on the brand. Prior researches found these inconsistent results related to the timing of the price promotion's exposure and quality evaluation relative to trial. And, whether the consumer has been experienced with the product promotions in the past or not may moderate the effects. A few studies considered differences among product categories as fundamental factors. The purpose of this research is to investigate the effect of price promotional informations on consumer's unfavorable quality perception under the different conditions. The author controlled the timing of the promotional exposure and varied past promotional patterns and information presenting patterns. Unlike previous researches, the author examined the effects of price promotions setting limit to pretrial situation by controlling potentially moderating effects of prior personal experience with the brand. This manipulations enable to resolve possible controversies in relation to this issue. And this manipulation is meaningful for the work sector. Price promotion is not only used to target existing consumers but also to encourage product or service trial among nonusers of products or services. Thus, it is important for marketers to understand how price promotional informations about a brand have impact on consumer's unfavorable quality perception of the brand. If consumers associate a price promotion itself with inferior quality about unused brand, the promotion may not achieve the sales increase the economic incentives otherwise might have produced. In addition, if the price promotion ends, the consumer that have purchased that certain brand will likely to display sharply decreased repurchasing behavior. Through a literature review, hypothesis 1 was set as follows to investigate the adjustive effect of past price promotion on quality perception made by consumers; The influence that price promotion of unused brand have on quality perception made by consumers will be adjusted by past price promotion activity of the brand. In other words, a price promotion of an unused brand that have not done a price promotion in the past will have a unfavorable effect on quality perception made by consumer. Hypothesis 2-1 was set as follows : When an unused brand undertakes price promotion for the first time, the information presenting pattern of price promotion will have an effect on the consumer's attribution for the cause of the price promotion. Hypothesis 2-2 was set as follows : The more consumer dispositionally attribute the cause of price promotion, the more unfavorable the quality perception made by consumer will be. Through test 1, the subjects were given a brief explanation of the product and the brand before they were provided with a $2{\times}2$ factorial design that has 4 patterns of price promotion (presence or absence of past price promotion * presence or absence of current price promotion) and the explanation describing the price promotion pattern of each cell. Then the perceived quality of imaginary brand WAVEX was evaluated in the scale of 7. The reason tennis racket was chosen is because the selected product group must have had almost no past price promotions to eliminate the influence of average frequency of promotion on the value of price promotional information as Raghubir and Corfman (1999) pointed out. Test 2 was also carried out on students of the same management faculty of test 1 with tennis racket as the product group. As with test 1, subjects with average familiarity for the product group and low familiarity for the brand was selected. Each subjects were assigned to one of the two cells representing two different information presenting patterns of price promotion of WAVEX (case where the reason behind price promotion was provided/case where the reason behind price promotion was not provided). Subjects looked at each promotional information before evaluating the perceived quality of the brand WAVEX in the scale of 7. The effect of price promotion for unfamiliar pretrial brand on consumer's perceived quality was proved to be moderated with the presence or absence of past price promotion. The consistency with past promotional behavior is important variable that makes unfavorable effect on brand evaluations get worse. If the price promotion for the brand has never been carried out before, price promotion activity may have more unfavorable effects on consumer's quality perception. Second, when the price promotion of unfamiliar pretrial brand was executed for the first time, presenting method of informations has impact on consumer's attribution for the cause of firm's promotion. And the unfavorable effect of quality perception is higher when the consumer does dispositional attribution comparing with situational attribution. Unlike the previous studies where the main focus was the absence or presence of favorable or unfavorable motivation from situational/dispositional attribution, the focus of this study was exaus ing the fact that a situational attribution can be inferred even if the consumer employs a dispositional attribution on the price promotional behavior, if the company provides a persuasive reason. Such approach, in academic perspectih sis a large significance in that it explained the anchoring and adjng ch approcedures by applying it to a non-mathematical problem unlike the previous studies where it wis ionaly explained by applying it to a mathematical problem. In other wordn, there is a highrspedency tmatispositionally attribute other's behaviors according to the fuedach aal attribution errors and when this is applied to the situation of price promotions, we can infer that consumers are likely tmatispositionally attribute the company's price promotion behaviors. Ha ever, even ueder these circumstances, the company can adjng the consumer's anchoring tmareduce the po wibiliute thdispositional attribution. Furthermore, unlike majority of previous researches on short/long-term effects of price promotion that only considered the effect of price promotions on consumer's purchasing behaviors, this research measured the effect on perceived quality, one of man elements that affects the purchasing behavior of consumers. These results carry useful implications for the work sector. A guideline of effectively providing promotional informations for a new brand can be suggested through the outcomes of this research. If the brand is to avoid false implications such as inferior quality while implementing a price promotion strategy, it must provide a clear and acceptable reasons behind the promotion. Especially it is more important for the company with no past price promotion to provide a clear reason. An inconsistent behavior can be the cause of consumer's distrust and anxiety. This is also one of the most important factor of risk of endless price wars. Price promotions without prior notice can buy doubt from consumers not market share.

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A Study on the Overall Economic Risks of a Hypothetical Severe Accident in Nuclear Power Plant Using the Delphi Method (델파이 기법을 이용한 원전사고의 종합적인 경제적 리스크 평가)

  • Jang, Han-Ki;Kim, Joo-Yeon;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.33 no.4
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    • pp.127-134
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    • 2008
  • Potential economic impact of a hypothetical severe accident at a nuclear power plant(Uljin units 3/4) was estimated by applying the Delphi method, which is based on the expert judgements and opinions, in the process of quantifying uncertain factors. For the purpose of this study, it is assumed that the radioactive plume directs the inland direction. Since the economic risk can be divided into direct costs and indirect effects and more uncertainties are involved in the latter, the direct costs were estimated first and the indirect effects were then estimated by applying a weighting factor to the direct cost. The Delphi method however subjects to risk of distortion or discrimination of variables because of the human behavior pattern. A mathematical approach based on the Bayesian inferences was employed for data processing to improve the Delphi results. For this task, a model for data processing was developed. One-dimensional Monte Carlo Analysis was applied to get a distribution of values of the weighting factor. The mean and median values of the weighting factor for the indirect effects appeared to be 2.59 and 2.08, respectively. These values are higher than the value suggested by OECD/NEA, 1.25. Some factors such as small territory and public attitude sensitive to radiation could affect the judgement of panel. Then the parameters of the model for estimating the direct costs were classified as U- and V-types, and two-dimensional Monte Carlo analysis was applied to quantify the overall economic risk. The resulting median of the overall economic risk was about 3.9% of the gross domestic products(GDP) of Korea in 2006. When the cost of electricity loss, the highest direct cost, was not taken into account, the overall economic risk was reduced to 2.2% of GDP. This assessment can be used as a reference for justifying the radiological emergency planning and preparedness.

The study of the relation between the medicine of Taoism and oriental medicine (도교의학(道敎醫學)에 관한 연구(硏究) (한의학(韓醫學)과 연관(聯關)된 부분(部分)을 중심(中心)으로))

  • Lee, Byung Sou;Yun, Chang Yul
    • Journal of Korean Medical classics
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    • v.6
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    • pp.252-305
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    • 1993
  • I have studied the relation between a Taoist(道家) and the oriental medicine(韓醫學), it is summerized as following. 1. According to the relation between a Taoist(道家) and the oriental medicine, Lao-tzu(老子)' mathematical principle that had an influence on Three yin-three yang(三陰三陽) theory of the oriental medicine, idea of natural philosopy(自然無爲) and the freedom from avarace(無慾) on the oriental medicine. 2. Vital essence and energy theory(精氣設) in a Taoist not only can be seen in Lao-tzu' Do dug gyung(老子道德經), Maengza(孟子), Guanza(管子), but also its principle has something to do with Nei Ching's Vital essence and energy theory(精氣設). 3. Danjungpa(丹鼎派) can be divided into Naedansul(內丹術) which preserves through the breath and Oedansul(外丹術) which makes one a Taoist hermit. If he takes magic portions(金丹), they had a great effect on Yangsanghak(養生學) and was actually concerned with oriental doctors who was known to us. 4. If medicine of Taoism is classified, it can be divided into three categories. Boiled solution(渴液), Pharmacopea "Ben cao"(本草), Acupuncture & moxibustion(針灸), Magic portions(外丹) are used in the first category. Chinese setting-up and Therapeutic exercises(導引), Josik(調息), Naedan(內丹), Byugok(辟榖), Naeshi(內視), Banjung(房中) belong to second category. The religious contents such as Bu(符), Jeum(占), Cheum(籤), Ju(呪), Je(齊), Gido(祈禱), taboo are implied in third category. 5. In the history of the medicine of Taoism and oriental medicine, they are called animism, shamanism, Mu(巫) or Ye(毉), not separated at first period. In the end of junguk(戰國時代), Ye(醫) was clearly distinguished from Mu(巫) and then Mu(巫) was developed into medicine of Taoism and ye(毉) into the present form of oriental medicine. 6. The oriental medicine doctors that are concerned with Taoism are Bakgo(伯高), Geyugu(鬼臾區), Soyu(少兪), Noigong(雷公), Pyujak(篇鵲), Sunuyi(淳于意), Hwata(華陀), Hwangbomil(皇甫謐), Hangang(韓康), Dongbong(童奉), Heuson(許遜), Galhong(葛洪), Dohongyung(陶弘景), Damlan(曇鸞), uyjajang(葦慈藏), Sonsanak(孫思邈), Wanguing(王氷), Jegonghwalbul(濟公活佛), Yuwanso(劉完素), Judonge(朱丹溪), Leesijin(李時珍), Johakmin(趙學敏), Ougu1(吳杰) etc. 7. The view of a human body in the medicine of Taoism affected the oriental medicine on the ground that man was regarded as a microcosm(小宇宙), so he was compared to a nation or heaven and earth. 8. The anatomy of medicine of Taoism gave a detail description of five visceras and each organs, the heart, center of mental function, Mirie(尾閭) which has an relationship to the training of Naedan(內丹修練). In this resrect, as it is accord with the acupunture point of oriental medicine, therefore we can find that Taoism influenced oriental medicine, also explicit study was achieved. 9. Acient people believed that the goo in the human lxxIy, one of the characteristics of the medicine of Taoism cured the patients and then protected him from the disease. If a man was taken ill, they had him cured by making the god's name which corresponded to its disease, calling him communicating with him, and asking him to deprive him of illness. This treatment was used to live and be kept young eternally. In this respects, we can see that they emphasized on the attitude of Bulchiyibeung chimibeung(不治己病治末病) and psychological treatment. 10. Samsi thoery(三尸說) that one's fortune, disaster, health, and disease in the world are at the mercy of his good or bad conduct, is concerned with Taoism and treatment with the oriental medicine. 11. Guchung(九蟲) is more closly associated with the religious aspect rather than with the medical aspect. Because of the similarity of the mcdern parasitism, its study has an important meaning. 12. The respect for the human life is reflected in jeunsi(傳屍), with Samsi-guchung theory(三尸九蟲說), which is considered as mxIern tuberculosis.

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Study of new adsorption isotherm model and kinetics of dissolved organic carbon in synthetic wastewater by granular activated carbon (입상활성탄에 의한 합성폐수의 용존유기물질의 새로운 흡착등온 모델 및 운동학적 흡착 연구)

  • Kim, Seoung-Hyun;Shin, Sunghoon;Kim, Jinhyuk;Woo, Dalsik;Lee, Hosun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.4
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    • pp.2029-2035
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    • 2014
  • In this study, we conducted the adsorption equilibrium and batch experiments of dissolved organic carbon (DOC) in the wastewater by granular activated carbon (GAC). The components of organic compound were Beef extract (1.8 mg/L), Peptone (2.7 mg/L), Humic acid (4.2 mg/L), Tannic acid (4.2 mg/L), Sodium lignin sulfonate (2.4 mg/L), Sodium lauryle sulfate (0.94 mg/L), Arabic gum powder (4.7 mg/L), Arabic acid (polysaccharide) (5.0 mg/L), $(NH_4)_2SO_4$ (7.1 mg/L), $K_2HPO_4$ (7.0 mg/L), $NH_4HCO_3$ (19.8 mg/L), $MgSO_4{\cdot}7H_2O$ (0.71 mg/L), The adsorption characteristics of DOC in synthetic wastewater was described using the mathematical model through a series of isotherm and batch experiments. It showed that there was linear adsorption region in the low DOC concentration (0~2.5 mg/L) and favorable adsorption region in high concentration (2.5~6 mg/L). The synthetic wastewater used was prepared using known quantities of organic and/or inorganic compounds. Adsorption modelling isotherms were predicted by the Freundlich, Langmuir, Sips and hybrid isotherm equations. Especially, hybrid isotherm of Linear and Sips equation was a good adsorption equilibrium in the region of the both the low concentration and high concentration. In applying carbon adsorption for treating water and wastewater, hybrid adsorption equation plus linear equation with Sips equation will be a good new adsorption equilibrium model. Linear driving force approximation (LDFA) kinetic equation with Hybrid (linear+Sips) adsorption isotherm model was successfully applied to predict the adsorption kinetics data in various GAC adsorbent amounts.

Development and Application of Integrative STEM (Science, Technology, Engineering and Mathematics) Education Model Based on Scientific Inquiry (과학 탐구 기반의 통합적 STEM 교육 모형 개발 및 적용)

  • Lee, Hyonyong;Kwon, Hyuksoo;Park, Kyungsuk;Oh, Hee-Jin
    • Journal of The Korean Association For Science Education
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    • v.34 no.2
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    • pp.63-78
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    • 2014
  • Integrative STEM education is an engineering design-based learning approach that purposefully integrates the content and process of STEM disciplines and can extend its concept to integration with other school subjects. This study was part of fundamental research to develop an integrative STEM education program based on the science inquiry process. The specific objectives of this study were to review relevant literature related to STEM education, analyze the key elements and value of STEM education, develop an integrative STEM education model based on the science inquiry process, and suggest an exemplary program. This study conducted a systematic literature review to confirm key elements for integrative STEM education and finally constructed the integrative STEM education model through analyzing key inquiry processes extracted from prior studies. This model turned out to be valid because the average CVR value obtained from expert group was 0.78. The integrative STEM education model based on the science inquiry process consisted of two perspectives of the content and inquiry process. The content can contain science, technology, engineering, and liberal arts/artistic topics that students can learn in a real world context/problem. Also, the inquiry process is a problem-solving process that contains design and construction and is based on the science inquiry. It could integrate the technological/engineering problem solving process and/or mathematical problem solving process. Students can improve their interest in STEM subjects by analyzing real world problems, designing possible solutions, and implementing the best design as well as acquire knowledge, inquiry methods, and skills systematically. In addition, the developed programs could be utilized in schools to enhance students' understanding of STEM disciplines and interest in mathematics and science. The programs could be used as a basis for fostering convergence literacy and cultivating integrated and design-based problem-solving ability.

Differences in Sleep Patterns are Related to Behavior, Emotional Problems, Attention and Academic Performance in Elementary School Students of a South Korean Metropolitan City (일 도시의 초등학교 학생의 수면습관과 행동, 정서, 주의력, 학습과의 관계)

  • Tak, Hee-Jong;Lee, Ji-Ho;Lee, Chang-Myung;Chung, Seok-Hoon;Lee, Jae-Won;Sim, Chang-Sun;Yoon, Jae-Goog;Sung, Joo-Hyeon;Bhang, Soo-Young
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.22 no.3
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    • pp.182-191
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    • 2011
  • Objectives: The aim of this study was to investigate the sleep patterns of South Korean elementary school children and whether the differences in sleep patterns were related to behavior, emotional problems, attention and academic performance. Method: This study included a community sample of 268 boys and girls from fourth-, fifth- and sixth-grade classes in a South Korean metropolitan city from November to December 2010. The primary caregivers completed a questionnaire that included information on demographic characteristics, as well as the Child's Sleep Habit Questionnaire (CSHQ), the Korean version of Child Behavior Checklist (K-CBCL), the Korean version of the Learning Disability Evaluation Scale (K-LDES), the Korean version of ADHD Rating Scale (K-ARS) and the Disruptive Behavior Disorder Scale (DBDS). We conducted analyses on the CSHQ individual items, between the subscales, on the total scores and on the K-CBCL, the K-LEDS, the K-ARS and the DBDS. Results: Based on the findings from the CHSQ, the subjects had significantly higher scores for bedtime resistance ($9.18{\pm}2.17$), delayed sleep onset ($1.32{\pm}0.62$), the sleep duration ($4.19{\pm}1.52$) and daytime sleepiness ($14.10{\pm}3.55$) than the scores from the previous reports on children from western countries. The total CHSQ score showed positive correlations to all subscales of the K-CBCL : withdrawn (r=0.24, p<.005), somatic complaint (r=0.24, p<.005) and anxious/depressive (r=0.38, p<.005). Bedtime resistance was associated with oppositional defiant disorder (r=0.15, p<.05) and a positive correlation was demonstrated between sleep anxiety and the oppositional defiant disorder score (r=0.13, p<.05), night waking and the conduct disorder score (r=0.16, p<.05). Delayed sleep onset was related with low performance on the K-LDES with respect to thinking (r=-0.17, p<.05) and mathematical calculation (r=-0.17, p<.05). Conclusion: The results of this study reconfirm Korean children's problematic sleep patterns. Taken together the results provide that the reduced sleep duration and disruption of sleep pattern can have a significant impact on emotion, behavior, performance of learning in children. Further studies concerning more diverse psychosocial factors affecting sleep pattern will be helpful to understanding of the sleep health in Korean children.

Comparison of Deep Learning Frameworks: About Theano, Tensorflow, and Cognitive Toolkit (딥러닝 프레임워크의 비교: 티아노, 텐서플로, CNTK를 중심으로)

  • Chung, Yeojin;Ahn, SungMahn;Yang, Jiheon;Lee, Jaejoon
    • Journal of Intelligence and Information Systems
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    • v.23 no.2
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    • pp.1-17
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    • 2017
  • The deep learning framework is software designed to help develop deep learning models. Some of its important functions include "automatic differentiation" and "utilization of GPU". The list of popular deep learning framework includes Caffe (BVLC) and Theano (University of Montreal). And recently, Microsoft's deep learning framework, Microsoft Cognitive Toolkit, was released as open-source license, following Google's Tensorflow a year earlier. The early deep learning frameworks have been developed mainly for research at universities. Beginning with the inception of Tensorflow, however, it seems that companies such as Microsoft and Facebook have started to join the competition of framework development. Given the trend, Google and other companies are expected to continue investing in the deep learning framework to bring forward the initiative in the artificial intelligence business. From this point of view, we think it is a good time to compare some of deep learning frameworks. So we compare three deep learning frameworks which can be used as a Python library. Those are Google's Tensorflow, Microsoft's CNTK, and Theano which is sort of a predecessor of the preceding two. The most common and important function of deep learning frameworks is the ability to perform automatic differentiation. Basically all the mathematical expressions of deep learning models can be represented as computational graphs, which consist of nodes and edges. Partial derivatives on each edge of a computational graph can then be obtained. With the partial derivatives, we can let software compute differentiation of any node with respect to any variable by utilizing chain rule of Calculus. First of all, the convenience of coding is in the order of CNTK, Tensorflow, and Theano. The criterion is simply based on the lengths of the codes and the learning curve and the ease of coding are not the main concern. According to the criteria, Theano was the most difficult to implement with, and CNTK and Tensorflow were somewhat easier. With Tensorflow, we need to define weight variables and biases explicitly. The reason that CNTK and Tensorflow are easier to implement with is that those frameworks provide us with more abstraction than Theano. We, however, need to mention that low-level coding is not always bad. It gives us flexibility of coding. With the low-level coding such as in Theano, we can implement and test any new deep learning models or any new search methods that we can think of. The assessment of the execution speed of each framework is that there is not meaningful difference. According to the experiment, execution speeds of Theano and Tensorflow are very similar, although the experiment was limited to a CNN model. In the case of CNTK, the experimental environment was not maintained as the same. The code written in CNTK has to be run in PC environment without GPU where codes execute as much as 50 times slower than with GPU. But we concluded that the difference of execution speed was within the range of variation caused by the different hardware setup. In this study, we compared three types of deep learning framework: Theano, Tensorflow, and CNTK. According to Wikipedia, there are 12 available deep learning frameworks. And 15 different attributes differentiate each framework. Some of the important attributes would include interface language (Python, C ++, Java, etc.) and the availability of libraries on various deep learning models such as CNN, RNN, DBN, and etc. And if a user implements a large scale deep learning model, it will also be important to support multiple GPU or multiple servers. Also, if you are learning the deep learning model, it would also be important if there are enough examples and references.

A Review Study on Major Factors Influencing Chlorine Disappearances in Water Storage Tanks (저수조 내 잔류염소 감소에 미치는 주요 영향 인자에 관한 문헌연구)

  • Noh, Yoorae;Kim, Sang-Hyo;Choi, Sung-Uk;Park, Joonhong
    • Journal of Korean Society of Disaster and Security
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    • v.9 no.2
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    • pp.63-75
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    • 2016
  • For safe water supply, residual chlorine has to be maintained in tap-water above a certain level from drinking water treatment plants to the final tap-water end-point. However, according to the current literature, approximately 30-60% of residual chlorine is being lost during the whole water supply pathways. The losses of residual chlorine may have been attributed to the current tendency for water supply managers to reduce chlorine dosage in drinking water treatment plants, aqueous phase decomposition of residual chlorine in supply pipes, accelerated chlorine decomposition at a high temperature during summer, leakage or losses of residual chlorine from old water supply pipes, and disappearances of residual chlorine in water storage tanks. Because of these, it is difficult to rule out the possibility that residual chlorine concentrations become lower than a regulatory level. In addition, it is concerned that the regulatory satisfaction of residual chlorine in water storage tanks can not always be guaranteed by using the current design method in which only storage capacity and/or hydraulic retention time are simply used as design factors, without considering other physico-chemical processes involved in chlorine disappearances in water storage tank. To circumvent the limitations of the current design method, mathematical models for aqueous chlorine decomposition, sorption of chlorine into wall surface, and mass-transfer into air-phase via evaporation were selected from literature, and residual chlorine reduction behavior in water storage tanks was numerically simulated. The model simulation revealed that the major factors influencing residual chlorine disappearances in water storage tanks are the water quality (organic pollutant concentration) of tap-water entering into a storage tank, the hydraulic dispersion developed by inflow of tap-water into a water storage tank, and sorption capacity onto the wall of a water storage tank. The findings from his work provide useful information in developing novel design and technology for minimizing residual chlorine disappearances in water storage tanks.