• Title/Summary/Keyword: Improvement design

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Review of Domestic Research Trends on Layered Double Hydroxide (LDH) Materials: Based on Research Articles in Korean Citation Index (KCI) (이중층수산화물(layered double hydroxide, LDH) 소재의 국내 연구동향 리뷰: 한국학술지인용색인(KCI)에 발표된 논문을 대상으로)

  • Seon Yong Lee;YoungJae Kim;Young Jae Lee
    • Economic and Environmental Geology
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    • v.56 no.1
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    • pp.23-53
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    • 2023
  • In this review paper, previous studies on layered double hydroxides (LDHs) published in the Korean Citation Index (KCI) were examined to investigate a research trend for LDHs in Korea. Since the first publication in 2002, 160 papers on LDHs have been published until January 2023. Among the 31 academic fields, top 5 fields appeared in the order of chemical engineering, chemistry, materials engineering, environmental engineering, and physics. The chemical engineering shows the highest record of published paper (71 papers) while around 10 papers have been published in the other four fields. All papers were reclassified into 15 research fields based on the industrial and academic purposes of using LDHs. The top 5 in these fields are in order of environmental purification materials, polymer catalyst materials, battery materials, pharmaceutical/medicinal materials, and basic physicochemical properties. These findings suggest that researches on the applications of LDH materials in the academic fields of chemical engineering and chemistry for the improvement of their functions such as environmental purification materials, polymer catalysts, and batteries have been being most actively conducted. The application of LDHs for cosmetic and agricultural purposes and for developing environmental sensors is still at the beginning of research. Considering a market-potential and high-efficiency-eco-friendly trend, however, it will deserve our attention as emerging application fields in the future. All reclassified papers were summarized in our tables and a supplementary file, including information on applied materials, key results, characteristics and synthesis methods of LDHs used. We expect that our findings of overall trends in LDH research in Korea can help design future researches with LDHs and suggest policies for resources and energies as well as environments efficiently.

Developments of Local Festival Mobile Application and Data Analysis System Applying Beacon (비콘을 활용한 위치기반 지역축제 모바일 애플리케이션과 데이터 분석 시스템 개발)

  • Kim, Song I;Kim, Won Pyo;Jeong, Chul
    • Korea Science and Art Forum
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    • v.31
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    • pp.21-32
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    • 2017
  • Local festivals form the regional cultures and atmosphere of communication; they increase the demand of domestic tourism businesses and thus, have an important role in ripple effects (e.g. regional image improvement, tourist influx, job creation, regional contents development, and local product sales) and economic revitalization. IoT (Internet of Thing) technologies have been developed especially, beacon-one of the IoT services has been applied as plenty of types and forms both domestically and internationally. However, notwithstanding expansion of current digital mobile technologies, it still remains as difficult for the individual to track the information about all the local festivals and to fulfill the tourists' needs of enjoying festivals given the weak strategic approaches and advertisement activities. Furthermore, current festival-related mobile applications don't function well as delivering information and have numerous contents issues (e.g. ways of information delivery within the festival places, independent application usage for each festival, one time usage due to one time event). This research, based on the background mentioned above, aims to develop the local festival mobile application and data analysis system applying beacon technology. First of all, three algorithms were developed, namely, 'festival crowding algorithm', 'visitor stats algorithm', and 'customized information algorithm', and then beta test was followed with the developed application and data analysis system. As a result, they could form the database of visitors' types and behaviors, and provide functions and services, such as personalized information, waiting time for festival contents, and 'hot place' function. Besides, in Google Play store, they also got the titles given with more than 13,000 downloads within first three months and as the most exposed application related with festivals; and, thus, got credited with their marketability and excellence. This research follows this order: chapter 2 shows the literature review of local festival related with technology development, beacon service, and festival application. In Chapter 3, design plans and conditions are described of developing local festival mobile application and data analysis system with beacon. Chapter 4 evaluates the results of the beta performance test to verify applicability of the developed application and data analysis system, and lastly, chapter 5 explains the conclusion and suggests the future research.

Behavior of Hollow Box Girder Using Unbonded Compressive Pre-stressing (비부착 압축 프리스트레싱을 도입한 중공박스 거더의 거동)

  • Kim, Sung Bae;Kim, Jang-Ho Jay;Kim, Tae Kyun;Eoh, Cheol Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3A
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    • pp.201-209
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    • 2010
  • Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.

Long-term Combined Exercise has Effect on Regional Bone Mineral Density and Cardiovascular Disease Risk Factors of the Elderly with Osteoporosis (장기간의 복합운동이 골다공증 노인의 신체부위별 골밀도와 심혈관질환 위험요인에 미치는 영향)

  • Choi, Pil-Byung
    • 한국노년학
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    • v.31 no.2
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    • pp.355-369
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    • 2011
  • The purpose of this study was to find the effects of long-term combined exercise on regional bone mineral density(BMD) and cardiovascular disease(CVD) risk factors in the elderly with osteoporosis(OP). For the purpose, the subjects of this study were separated by two groups with thirty-one elderly women, who the first group was combined exercise group(CEG, n=16) and second group was non exercise group(CON, n=15). The combined exercise program was made up of warm-up (10min), work-out (aerobic; 30~45min/HRR 40~60%, resistance; 1RM * 50-70%, 8-10 * 2set ~ 10-15 * 1set), and cool-down (10min). Exercise group of the inspection have been trained 5 times a week for 1years. The results : At first, the variables of regional BMD were significantly different to pelvis, spine, trunk and T-score in two groups. At second, the variables of CVD risk factors were significantly different to SBP and DBP as well as TC, TG, LDL-C and HDL-C in two groups. As results of these conclusion, this study have positively effect shown that CEG was superior to CON in regional BMD(pelvis, spine, trunk and T-score), blood pressure(SBP, DBP) and plasma lipids(TC, TG, and LDL-C). Especially, the long-term combined exercise was provides a striking overall health quality of life with improving BMD and reduced CVD risk factors in the elderly with OP. In the future, other researches should deal with specific measures that reduction in mortality due to chronic disease and improvement quality of life for the development of programs in multiple researches of osteoporosis and chronic diseases.

Establishment of Safety Factors for Determining Use-by-Date for Foods (식품의 소비기한 참고치 설정을 위한 안전계수)

  • Byoung Hu Kim;Soo-Jin Jung;June Gu Kang;Yohan Yoon;Jae-Wook Shin;Cheol-Soo Lee;Sang-Do Ha
    • Journal of Food Hygiene and Safety
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    • v.38 no.6
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    • pp.528-536
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    • 2023
  • In Korea, from January 2023, the Act on Labeling and Advertising of Food was revised to reflect the use-by-date rather than the sell-by-date. Hence, the purpose of this study was to establish a system for calculating the safety factor and determining the recommended use-by-date for each food type, thereby providing a scientific basis for the recommended use-by-date labels. A safety factor calculation technique based on scientific principles was designed through literature review and simulation, and opinions were collected by conducting surveys and discussions including industry and academia, among others. The main considerations in this study were pH, Aw, sterilization, preservatives, packaging for storage improvement, storage temperature, and other external factors. A safety factor of 0.97 was exceptionally applied for frozen products and 1.0 for sterilized products. In addition, a between-sample error value of 0.08 was applied to factors related to product and experimental design. This study suggests that clearly providing a safe use-by-date will help reduce food waste and contribute to carbon neutrality.

Analysis of the Effectiveness of a University Affiliated Science-Gifted Educational Program: The Case of C Gifted Education Center (C 영재교육원을 통해 살펴본 대학부설 과학영재교육원 프로그램 효과성 분석)

  • Han, Ki-Soon;Yang, Tae-Youn
    • Journal of The Korean Association For Science Education
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    • v.29 no.2
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    • pp.137-155
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    • 2009
  • The purpose of the present study was to analyse the effectiveness of a gifted education program. To analyse the effectiveness of an education program for the gifted affiliated with a university, the study carried out a quasi-experimental design to compare the 153 gifted students who enrolled in an education center for the gifted and the 131 potentially gifted students who were nominated by teachers for their high achievements and interests in science but without any education services for the gifted. These two groups of students were compared in the aspects of problem finding ability in science, motivation, self regulation, science-related attitudes, and science anxiety through the pre- and post-treatment settings. The results indicated that the gifted group showed a significant improvement in originality and elaboration of problem-finding ability, but the potentially gifted group showed significant decrease in most variables of problem finding. Related to motivation and self-regulated learning, gifted students showed an increase in cognitive strategy use and decrease in intrinsic value, but the potentially gifted students showed significant decreases in most variables related to motivation and self-regulation, except intrinsic value. Related to the scientific attitudes and science anxiety, there were no significant changes between pre- and post-tests in the gifted group, but significant decreases in most variables were found in the potentially gifted group. The results of paired t-test and Ancova indicate that significant differences between the gifted and the potentially gifted groups are mainly due to the significantly lowered performance in post tests in the potentially gifted group, rather than a significant increase in gifted group.

Exploring Pre-Service Earth Science Teachers' Understandings of Computational Thinking (지구과학 예비교사들의 컴퓨팅 사고에 대한 인식 탐색)

  • Young Shin Park;Ki Rak Park
    • Journal of the Korean earth science society
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    • v.45 no.3
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    • pp.260-276
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    • 2024
  • The purpose of this study is to explore whether pre-service teachers majoring in earth science improve their perception of computational thinking through STEAM classes focused on engineering-based wave power plants. The STEAM class involved designing the most efficient wave power plant model. The survey on computational thinking practices, developed from previous research, was administered to 15 Earth science pre-service teachers to gauge their understanding of computational thinking. Each group developed an efficient wave power plant model based on the scientific principal of turbine operation using waves. The activities included problem recognition (problem solving), coding (coding and programming), creating a wave power plant model using a 3D printer (design and create model), and evaluating the output to correct errors (debugging). The pre-service teachers showed a high level of recognition of computational thinking practices, particularly in "logical thinking," with the top five practices out of 14 averaging five points each. However, participants lacked a clear understanding of certain computational thinking practices such as abstraction, problem decomposition, and using bid data, with their comprehension of these decreasing after the STEAM lesson. Although there was a significant reduction in the misconception that computational thinking is "playing online games" (from 4.06 to 0.86), some participants still equated it with "thinking like a computer" and "using a computer to do calculations". The study found slight improvements in "problem solving" (3.73 to 4.33), "pattern recognition" (3.53 to 3.66), and "best tool selection" (4.26 to 4.66). To enhance computational thinking skills, a practice-oriented curriculum should be offered. Additional STEAM classes on diverse topics could lead to a significant improvement in computational thinking practices. Therefore, establishing an educational curriculum for multisituational learning is essential.

Exhibition Hall Lighting Design that Fulfill High CRI Based on Natural Light Characteristics - Focusing on CRI Ra, R9, R12 (자연광 특성 기반 고연색성 실현 전시관 조명 설계 - CRI Ra, R9, R12를 중심으로)

  • Ji-Young Lee;Seung-Teak Oh;Jae-Hyun Lim
    • Journal of Internet Computing and Services
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    • v.25 no.4
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    • pp.65-72
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    • 2024
  • To faithfully represent the intention of the work in the exhibition space, lighting that provides high color reproduction like natural light is required. Thus, many lighting technologies have been introduced to improve CRI, but most of them only evaluated the general color rendering index (CRI Ra), which considers eight pastel colors. Natural light provides excellent color rendering performance for all colors, including red and blue, expressed by color rendering index of R9 and R12, but most artificial lighting has the problem that color rendering performance such as R9 and R12 is significantly lower than that of natural light. Recently, lighting technology that provides CRI at the level of natural light is required to realistically express the colors of works including primary colors but related research is very insufficient. Therefore this paper proposes exhibition hall lighting that fulfills CRI with a focus on CRI Ra, R9, and R12 based on the characteristics of natural light. First reinforcement wavelength bands for improving R9 and R12 are selected through analysis of the actual measurement SPD of natural and artificial lighting. Afterward virtual SPDs with a peak wavelength within the reinforcement wavelength band are created and then SPD combination conditions that satisfy CRI Ra≥95, R9, and R12≥90 are derived through combination simulation with a commercial LED light source. Through this, after specifying two types of light sources with 405,630nm peak wavelength that had the greatest impact on the improvement of R9 and R12, the exhibition hall lighting applied with two W/C White LEDs is designed and a control Index DB of the lighting is constructed. Afterward experiments with the proposed method showed that it was possible to achieve high CRI at the level of natural light with average CRI Ra 96.5, R9 96.2, and R12 94.0 under the conditions of illuminance (300-1,000 Lux) and color temperature (3,000-5,000K).

Feasibility of Deep Learning Algorithms for Binary Classification Problems (이진 분류문제에서의 딥러닝 알고리즘의 활용 가능성 평가)

  • Kim, Kitae;Lee, Bomi;Kim, Jong Woo
    • Journal of Intelligence and Information Systems
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    • v.23 no.1
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    • pp.95-108
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    • 2017
  • Recently, AlphaGo which is Bakuk (Go) artificial intelligence program by Google DeepMind, had a huge victory against Lee Sedol. Many people thought that machines would not be able to win a man in Go games because the number of paths to make a one move is more than the number of atoms in the universe unlike chess, but the result was the opposite to what people predicted. After the match, artificial intelligence technology was focused as a core technology of the fourth industrial revolution and attracted attentions from various application domains. Especially, deep learning technique have been attracted as a core artificial intelligence technology used in the AlphaGo algorithm. The deep learning technique is already being applied to many problems. Especially, it shows good performance in image recognition field. In addition, it shows good performance in high dimensional data area such as voice, image and natural language, which was difficult to get good performance using existing machine learning techniques. However, in contrast, it is difficult to find deep leaning researches on traditional business data and structured data analysis. In this study, we tried to find out whether the deep learning techniques have been studied so far can be used not only for the recognition of high dimensional data but also for the binary classification problem of traditional business data analysis such as customer churn analysis, marketing response prediction, and default prediction. And we compare the performance of the deep learning techniques with that of traditional artificial neural network models. The experimental data in the paper is the telemarketing response data of a bank in Portugal. It has input variables such as age, occupation, loan status, and the number of previous telemarketing and has a binary target variable that records whether the customer intends to open an account or not. In this study, to evaluate the possibility of utilization of deep learning algorithms and techniques in binary classification problem, we compared the performance of various models using CNN, LSTM algorithm and dropout, which are widely used algorithms and techniques in deep learning, with that of MLP models which is a traditional artificial neural network model. However, since all the network design alternatives can not be tested due to the nature of the artificial neural network, the experiment was conducted based on restricted settings on the number of hidden layers, the number of neurons in the hidden layer, the number of output data (filters), and the application conditions of the dropout technique. The F1 Score was used to evaluate the performance of models to show how well the models work to classify the interesting class instead of the overall accuracy. The detail methods for applying each deep learning technique in the experiment is as follows. The CNN algorithm is a method that reads adjacent values from a specific value and recognizes the features, but it does not matter how close the distance of each business data field is because each field is usually independent. In this experiment, we set the filter size of the CNN algorithm as the number of fields to learn the whole characteristics of the data at once, and added a hidden layer to make decision based on the additional features. For the model having two LSTM layers, the input direction of the second layer is put in reversed position with first layer in order to reduce the influence from the position of each field. In the case of the dropout technique, we set the neurons to disappear with a probability of 0.5 for each hidden layer. The experimental results show that the predicted model with the highest F1 score was the CNN model using the dropout technique, and the next best model was the MLP model with two hidden layers using the dropout technique. In this study, we were able to get some findings as the experiment had proceeded. First, models using dropout techniques have a slightly more conservative prediction than those without dropout techniques, and it generally shows better performance in classification. Second, CNN models show better classification performance than MLP models. This is interesting because it has shown good performance in binary classification problems which it rarely have been applied to, as well as in the fields where it's effectiveness has been proven. Third, the LSTM algorithm seems to be unsuitable for binary classification problems because the training time is too long compared to the performance improvement. From these results, we can confirm that some of the deep learning algorithms can be applied to solve business binary classification problems.

The Effects of Supplemental Bacterial Phytase to the Calcium and Nonphosphorus Levels in Feed of Laying Hens (산란계 사료 내 칼슘 및 무기태 인 수준에 따른 Bacterial Phytase 급여 효과)

  • Kang, H.K.;Park, S.Y.;Yu, D.J.;Kim, J.H.;Kang, G.H.;Na, J.C.;Kim, D.W.;Suh, O.S.;Lee, S.J.;Lee, W.J.;Kim, S.H.
    • Korean Journal of Poultry Science
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    • v.35 no.2
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    • pp.143-151
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    • 2008
  • This study was conducted to identify the correlation of bacterial phytase ($Transphos^{(R)}$) to the calcium level in feed. Of all 21-week-old 720 HyLine brown laying hens, 2 birds of similar weight were placed on each individual cage. The experiment was conducted by $3{\times}2{\times}3$ factorial design with including 3 different levels of phytase (0, 300, and 1,000 DPU/kg), 2 different levels of calcium (3.5% and 4.0%), and 3 different levels of no NPP addition 0% (0.095 NPP), 0.5% (0.185% NPP), and 1.0% (0.275% NPP). The feeding trial maintained the ME level of 2,800 kcal/kg and 16% for crude protein. The diet was fed ad libitum and 17 hours of lighting was provided throughout the experimental period. Egg production seemed to increase, in the 300 DPU of bacterial phytase added group and the cracked egg tended to reduce in Transphos added group. The egg productivity between treatment groups did not show significant difference by dietary calcium level, whereas non NPP added group (0.095% NPP) was found to be low compared to NPP added groups (P<0.05). The highest mean egg weight and the highest daily egg mass were detected in 300 DPU phytase added group. Although the mean egg weight was significantly higher in treatment groups fed with 3.5% calcium containing feeds (P<0.05), daily egg mass was no among treatment groups. The mean egg weight and daily egg mass were the lowest in non NPP added group (0.095% NPP) compared to other treatment groups (P<0.05). The feed intake showed similar pattern regardless of the bacterial phytase and calcium levels in the diet. However, the treatment groups fed diets containing NPP level of 0.275% and 0.165% showed significantly higher feed intake than the group fed with 0.095% NPP (P<0.05). Although the feed conversion was not affected by calcium and NPP levels in the diet, the most improved result was obtained from 300 DPU phytase added group (P<0.05). The eggshell breaking strength and thickness increased as dietary calcium level increase the level of calcium increases in diet. The treatment groups fed diet containing 0.275% and 0.165% NPP revealed to show improvement in eggshell breaking strength and yolk color index compared to the NPP non added (0.095% NPP) treatment group. The result of the present study suggests that the appropriate level of microbial phytase is 300 DPU and at this level, tricalciumphosphate supplementation in feed can be reduced to 40% of NRC recommendation. Higher calcium level in feed fail to show synergistic effect by adding microbial phytase.