• International Journal of Computer Science & Network Security
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• v.24 no.6
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• pp.67-76
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• 2024

The Internet of Things (IoT) has revolutionized communication and device operation, but it has also brought significant security challenges. IoT networks are structured into four levels: devices, networks, applications, and services, each with specific security considerations. Personal Area Networks (PANs), Local Area Networks (LANs), and Wide Area Networks (WANs) are the three types of IoT networks, each with unique security requirements. Communication protocols such as Wi-Fi and Bluetooth, commonly used in IoT networks, are susceptible to vulnerabilities and require additional security measures. Apart from physical security, authentication, encryption, software vulnerabilities, DoS attacks, data privacy, and supply chain security pose significant challenges. Ensuring the security of IoT devices and the data they exchange is crucial. This paper utilizes the Random Forest Algorithm from machine learning to detect anomalous data in IoT devices. The dataset consists of environmental data (temperature and humidity) collected from IoT sensors in Oman. The Random Forest Algorithm is implemented and trained using Python, and the accuracy and results of the model are discussed, demonstrating the effectiveness of Random Forest for detecting IoT device data anomalies.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.4
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• pp.51-57
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• 2024

This study was conducted on how to simulate runoff, which was done using existing physical models, using an LSTM (Long Short-Term Memory) model based on deep learning. Tancheon, the first tributary of the Han River, was selected as the target area for the model application. To apply the model, one water level observatory and four rainfall observatories were selected, and hourly data from 2020 to 2023 were collected to apply the model. River water level of the outlet of the Tancheon basin was simulated by inputting precipitation data from four rainfall observation stations in the basin and average preceding 72-hour precipitation data for each hour. As a result of water level simulation using 2021 to 2023 data for learning and testing with 2020 data, it was confirmed that reliable simulation results were produced through appropriate learning steps, reaching a certain mean absolute error in a short period time. Despite the short data period, it was found that the mean absolute percentage error was 0.5544~0.6226%, showing an accuracy of over 99.4%. As a result of comparing the simulated and observed values of the rapidly changing river water level during a specific heavy rain period, the coefficient of determination was found to be 0.9754 and 0.9884. It was determined that the performance of LSTM, which aims to simulate river water levels, could be improved by including preceding precipitation in the input data and using precipitation data from various rainfall observation stations within the basin.

• Journal of Korea Society of Digital Industry and Information Management
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• v.20 no.2
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• pp.11-25
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• 2024

This study aims to analyze research trends in digital twin focusing on Germany, the US, and Korea. In Elsevier's Scopus, we collected 4,657 papers about digital twin published in from 2019 to 2023. Keyword frequency and centrality analysis were conducted on the abstracts of the collected papers. Through the obtained keyword frequencies, we tried to identify keywords with high frequency of occurrence and through centrality analysis, we tried to identify central research keywords for each country. In each country, 'digital_twin', 'machine_learning', and 'iot' appeared as research keywords with the highest interest. As a result of the centrality analysis, research on digital twin, simulation, cyber physical system, Internet of Things, artificial intelligence, and smart manufacturing was conducted as research with high centrality in each country. The implication for Korea is that research on virtual reality, digital transformation, reinforcement learning, industrial Internet of Things, robotics, and data analysis appears to have been conducted with low centrality, and intensive research in related areas appears to be necessary.

• International Journal of Advanced Culture Technology
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• v.12 no.3
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• pp.471-479
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• 2024

Recent advancements in cloud computing have significantly increased its importance across various sectors. As sensors, devices, and customer demands have become more diverse, workloads have become increasingly variable and difficult to predict. Cloud providers, connected to multiple physical servers to support a range of applications, often over-provision resources to handle peak workloads. This approach results in inconsistent services, imbalanced energy usage, waste, and potential violations of service level agreements. In this paper, we propose a novel engine equipped with a scheduler based on the Hot-Threshold concept, aimed at optimizing resource usage and improving energy efficiency in cloud environments. We developed this engine to employ both proactive and reactive methods. The proactive method leverages workload estimate-based provisioning, while the reactive Hot-Cold Scheduler consists of a Predictor, Solver, and Processor, which together suggest an intelligent migration flow. We demonstrate that our approach effectively addresses existing challenges in terms of cost and energy consumption. By intelligently managing resources based on past user statistics, we provide significant improvements in both energy efficiency and service consistency.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.80-87
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• 2017

Purpose: The aim of this study was to assess the physical properties of a novel resin-based endodontic sealer, Any-Seal, in comparison with AH Plus Jet. Materials and Methods: Flow, radiopacity and compressive strength were examined according to ISO 6876/2001. For flow test, 0.05 mL of sealer was placed between glass plate and 100 g weight were applied. Ten minutes after mixing the sealers, the load was removed and the diameters of the compressed sealer discs were measured. For radiopacity, 10 mm diameter and 1 mm thickness sample were fabricated and took radiograph with an aluminum step-wedge and analyzed using imaging program. For compressive strength test, $4mm{\times}6mm$ cylindrical specimen was fabricated and tested after 24 hours and 1 week using Universal testing machine. Results: Both tested sealers were consistent with ISO 6876/2001 in the flow and radiopacity test. The flow values of both sealers were not significantly different (P > 0.05). AH Plus Jet had significantly higher radiopacity (P < 0.05). AH Plus Jet showed higher compressive strength at both time intervals (P < 0.05). Conclusion: Any-Seal showed low compressive strength until after 1 week, so its physical and biological aspect should be evaluated more before clinical use.

• Journal of the Korean Dietetic Association
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• v.13 no.1
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• pp.73-83
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• 2007

In order to investigate the ecological factors affecting milk intake frequency of adolescents, the questionnaire survey was conducted with 929 middle and high school students living in Chungnam urban area through October and November 2004. The subjects consumed milk 8.6$\pm$6.7 times per week, other beverages 4.4$\pm$4.1 times per week and drinking water 3.7$\pm$2.1 cups per day. Of the students 77.3% took balanced meals, 72.8% ate regularly and 36.2% ate adequate amount. About 61% had breakfast everyday and nearly a half students snacked once a day. Nutritional knowledge scores about milk was 7.2$\pm$1.7 and milk attitude scores was 28.1$\pm$6.5. The subjects spent daily 1.8$\pm$1.1, 1.9$\pm$1.1, and 1.0$\pm$0.5 hours for computer use, TV watching and exercise, respectively. Milk intake frequencies were positively correlated with excercise, snack frequency, meal balance and regularity, breakfast frequency, food attitude score and milk preference, while showed negative correlationships with TV watching and computer use. Intake frequency of fruit-tasted and chocolate milk showed inverse correlation with nutritional knowledge. Subjects without either school store or vending machine took milk more frequently than those with one or both did. Of the correlated variables, milk preference was the most important influencing factor to milk intake frequency according to the stepwise linear regression analysis, which presented other 5 important influencing factors as food attitude, school vending facilities, excercise, snacking frequency and watching TV. In conclusion, the improvement of milk preference is the most important and effective way to promote milk consumption in adolescents. The favorite ways of drinking milk, nutritional benefit of milk, healthy beverage and good snacking should be taught in nutrition education. Also physical activities should be recommended to students rather than watching TV, computer use and vending facilities selling soft drinks should be limited to be established inside school.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.846-852
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• 2012

The physical properties of instant puffed rice snacks with non-glutinous, glutinous, and steamed non-glutinous rice were evaluated at different moisture content and puffing temperatures. Raw materials were tempered to 9%, 12%, 15%, and 18% moisture content and puffed at $200^{\circ}C$, $210^{\circ}C$ and $220^{\circ}C$. With the increase in moisture content and puffing temperature, puffed snacks were less bulky. As the moisture content decreased and puffing temperature increased, the whiteness (L) value of puffed snacks decreased, while the redness (a) and yellowness (b) values increased. WSI and WAI were higher with an increase in moisture content and puffing temperature. Instant puffed rice snacks made from non-glutinous, glutinous, and steamed non-glutinous rice showed differences in bulk density, WSI, and WAI, while no difference was found in color values. When the moisture content increased from 9% to 15%, the cells within the products became more uniform and smaller. The instant puffed rice snacks made from glutinous rice showed the smallest and most uniform cell structure.

• The Journal of Korean Physical Therapy
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• v.16 no.4
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• pp.90-114
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• 2004

This study was conducted to examine the influence and effect of muscle enforcement program on Activity of daily living(ADL) improvement and posture balance of the old, and to provide more effective muscle enforcement program and educational data. The muscle enforcement exercise program was performed on the old(institution, 16 men, 10 women) for 8 weeks from April 22, 2002 through June 17,2002. Programed Exercise 1 - Exercise 10 were practised 8 times per program for 3 days a week. The load of exercise was increased per two weeks. The methods of measurement were questionnaire, Indiana 47903(action-response analysis machine) and Sample exercise protocol for KAT 2000(balance training device). SAS/PC statistic analysis was used for data analysis. T-test was used for analysis of change before and after exercise in this study. The summary and conclusions are as follows. 1. On subjectively recognized health states, the healthy were $42.3\%$. On the satisfaction with health states, the satisfied were $50.0\%$. On the factors of effects on daily-life behavior performance, the group who had troubles was $50\%$ and the group who was so and so was $34.6\%$ compared with the old of the same age. On prospect about health states in the future, the group who would be better was $38.\%$. On effective methods for problem solving, exercise was $42.3\%.\;88.5\%$ of respondents answered the need of health care. The participation intention in health program was $92.3\%$. 2. On the change of psychological emotion and behavior aspects, the group who had repeated complaints or anxieties and reduced activities or interests was effective(P<0.01). 3. On the improvement effects of IADL difficulties, the group who had difficulties in doing daily-life indoors was improved effectively compared with before and after exercise(P<0.01). On medication management, the effects of improvement after exercise were high compared with before exercise(P<0.01), the effects of improvement was high on the whole. 4. On the effects of ADL function improvement, putting on upper clothing and lower clothing was improved effectively(P<0.05), toilet use and individual sanitation was improved effectively(P<0.05). 5. On the effects of action-response, the results of 8weeks regular exercise program were not different significantly compared with before and after exercise. The behavior quickness of the old by muscle enforcement program was not increased. This means that the old needs much time for exercise sense training because of the regression of cognition sense. 6. In the effect of posture balance, the whole grades were effective from 1272.69 before excercise to 476.92 after exercise(P<0.01). Especially right balance 657.65 was lowered to 208.57 after exercise most effectively(P<0.01). Rear balance 776.34 before exercise was lowered to 136.65 after exercise. The results of measurement were significant(P<0.05).

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.443-450
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• 2009

Purpose: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. Materials and Methods: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. Results: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. Conclusion: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.287-292
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• 2018

The digital multimedia environment, centered on Information and Communications Technologies (ICT) technology, has transformed our imagination into a diverse experience. The flexible display, which was born as a means of human-machine communication required in a highly information-oriented society, It is creating a new market by linking with Internet of things. ecause the interface of a flexible display can provide a physical form as a result of input or output, user-centered interface design is paramount. Therefore, the researchers of this paper have studied the physical deformation and characteristics of flexible display by user manipulation through literature and case studies. Therefore, the authors of this paper studied the physical deformations and characteristics of flexible displays by user manipulation through literature and case studies. This research suggests the following guidelines for a flexible display interface design for the user experience. First, it must be designed to provide the functionality that users need in a variety of display environments. Second, in using the interface, external factors should be removed from the viewing angle of multi-users. Third, all possible user actions should be considered on flexible displays other than touch and contact. Fourth, flexible design of flexible display requires changing interface design for user experience.