• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.369-372
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• 2021

These days, people spend more time sitting at a desk for studies or work. Also, because people continue to use computers, smartphones, and tablet PCs often during break times, their posture is getting worse. Maintaining a position of bad posture for an extended period of time causes problems with the musculoskeletal system related to the neck, shoulders, and spine. Additionally, problems such as physical fatigue and posture deformation are predicted to expand to a wide range of age groups. Therefore, the core function of the system we are developing is to ensure correct sitting posture and to receive alert notifications via the created mobile application. To create the system, a flex sensor, pressure sensor, and tilt sensor are attached to a chair and utilized. The flex sensor detects and compares the amount of bending in the chair's posture and transmits this value to an Arduino Uno R3 board. Additionally, information such as body balance and incline angle are collected to determine whether or not the current sitting posture is correct. When the posture is incorrect, a notification is sent through the mobile application to indicate to the user and the monitoring app that their posture is not correct. The system proposed in this study is expected to be of great help in future posture-related research.

• Journal of Cadastre & Land InformatiX
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• v.53 no.1
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• pp.21-36
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• 2023

Activity-based modeling systems have increasingly been developed to address the limitations of widely used traditional four-step transportation demand forecasting models. Accordingly, this paper introduces the Activity-BAsed Traveler Analyzer (ABATA) system. This system consists of multiple components, including an hourly total population estimator, activity profile constructor, hourly activity population estimator, spatial activity population estimator, and origin/destination estimator. To demonstrate the proposed system, the emission impact of land use changes in the 5-1 block Sejong smart city is evaluated as a case study. The results indicate that the land use with the scenario of work facility dispersed plan produced more emissions than the scenario of work facility centralized plan due to the longer travel distance. The proposed ABATA system is expected to provide a valuable tool for simulating the impacts of future changes in population, activity schedules, and land use on activity populations and travel demands.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.359-367
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• 2023

In order to ensure the high-integrity of reference stations of satellite navigation system, cycle slip should be precisely monitored and compensated. In this paper, we proposed a cycle slip algorithm for the integrity monitoring of the reference stations. Unlike the legacy method using the Melbourne-Wübbena (MW) combination and ionosphere combination, the proposed algorithm is based on ionosphere combination only, which uses high precision carrier phase observations without pseudorange observations. Two independent and complementary ionosphere combinations, Ionospheric Negative (IN) and Ionospheric Positive (IP), were adopted to avoid insensitive cycle slip pairs. In addition, a second-order time difference was applied to the IN and IP combinations to minimize the influence of ionospheric and tropospheric delay even under severe atmosphere conditions. Then, the cycle slip was detected by the thresholds determined based on error propagation rules, and the cycle slip was identified through weighted least square method. The performance of the proposed cycle slip algorithm was validated with the 1 Hz dual-frequency carrier phase data collected under the difference levels of ionospheric activities. For this experiment, 15 insensitive cycle slip pairs were intentionally inserted into the raw carrier phase observations, which is difficult to be detected with the traditional cycle slip approach. The results indicate that the proposed approach can successfully detect and compensate all of the inserted cycle slip pairs regardless of ionospheric activity. As a consequence, the proposed cycle slip algorithm is confirmed to be suitable for the reference station where real time high-integrity monitoring is crucial.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.2
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• pp.47-54
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• 2024

The global decrease in traditional energy resources has prompted increasing energy demand, necessitating efforts to replace and optimize energy sources. This study focuses on enhancing energy efficiency in manufacturing plants, known for their high energy consumption. Through simulations and analyses, the study proposes a temperature-based control system for HVAC (Heating, Ventilating, and Air Conditioning) operations, utilizing machine learning algorithms to predict and optimize factory temperatures. The results indicate that this approach, particularly the prediction-based free cooling algorithm, can achieve over 10% energy savings compared to existing systems. This paper presents that implementing an efficient HVAC control system can significantly reduce overall factory energy consumption, with plans to apply it to real factories in the future.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.69-78
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• 2024

Recently, consumers have shown an increasing tendency to seek information related to environmental, social, and governance (ESG) aspects in order to choose products with higher social value and environmental friendliness. In this paper, we proposes a product recommendation system applying ESG indicators tailored to the recent consumer trend of value-based consumption, utilizing a model called MultiSAGE that combines GraphSAGE and GAT. To achieve this, ESG rating data for 1,033 companies in 2022 collected from the Korea ESG Standard Institute and actual product data from N companies were transformed into a Heterogeneous Graph format through a data processing pipeline. The MultiSAGE model was then applied in machine learning to implement a recommendation system that, given a specific product, suggests eco-friendly alternatives. The implementation results indicate that consumers can easily compare and purchase products with ESG indicators applied, and it is anticipated that this system will be utilized in recommending products with social value and environmental friendliness.

• Science of Emotion and Sensibility
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• v.26 no.4
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• pp.125-132
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• 2023

This study investigated the effects of continuous Singing Bowl healing on brainwaves and autonomic nervous system responses. The variations in brainwaves were measured during 45-minute sessions in eight participants, before and after Singing Bowl healing sessions to assess the changes in brainwaves before and after five weeks of Singing Bowl healing treatment. BioBrain BIOS-S8 was used to obtain brainwave measurements. Electrodes were placed on six channels: F3, F4, T3, T4, P3, and P4. A standard limb lead I with electrodes was used for electrocardiogram (ECG) measurements. Using the collected brainwave data, changes in brain waves were observed before and after five weeks of Singing Bowl healing. Beta waves, alpha waves, and sensorimotor rhythm were found to have reduced, while theta waves, delta waves, and the standard deviation of normal-to-normal intervals in heart rate variability had increased. These results indicate that continuous Singing Bowl healing over five weeks can stabilize brainwaves, activate the autonomic nervous system, and increase the relaxation-inducing effects of the parasympathetic nervous system.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.609-617
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• 2024

Research on information system supervision services was mainly interested in supervision service standards or legislation, but this study identified the factors that ordering agencies consider important when introducing/advancing information systems and then looked at the information system from the ordering agency's perspective. According to the research results, (1) ordering organizations consider innovation factors the most important when introducing/advancing information systems, (2) organizational culture and the will of the CEO are still important factors, and (3) innovation factors are more important than technology factors. The results of this study indicate that the participation of information system supervision experts is required not only from the technical aspect of the constructed information system, but also from the organizational aspect of the ordering agency.

• Economic and Environmental Geology
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• v.51 no.5
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• pp.439-453
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• 2018

The Eocene Gyeongju granitoids in SE Korea are alkali feldspar granite (AGR), biotite granite (BTGR), and hornblende biotite granodiorite (HBGD) along Yangsan fault and Ulsan fault. According to their geochemical characteristics, these granitoids are classified as A-type (AGR) and I-type (BTGR and HBGD) granitoids, and regarded that were derived from same parental magma in upper mantle. The hornblende and biotite of AGR as an interstitial phase indicate that influx of F-rich fluid during the crystallization of AGR magma. AGR is enriched LILE (except Sr and Ba) and LREE that indicate the influences for subduction released fluids. The highest HFSE contents and zircon saturation temperature of AGR among the Eocene Gyeongju granitoids may indicate that it was affected by partial melting rather than magma fractionation. These characteristics may represent that the high F contents of AGR was affected by F-rich fluid derived from the subducted slab and partial melting. It corresponds with the results of the REE modeling and the dehydrated fluid component (Ba/Th) modeling showing that AGR (A-type) was formed by the partial melting of BTGR (I-type) with the continual influx of F-rich fluid derived from the subducted slab.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.103-110
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• 2005

Opuntia ficus-indica, commonly known as prickly pear cactus, is commercially grown as a food and medicinal plant in Jeju Island, Korea. The crushed pads and fruits of Opuntia ficus-indica were dried in a freeze-dryer and ground into flour to be used for food materials. The major components of proximate compositions were part of a nitrogen free extract. The major minerals were Ca (4391.2-2086.9㎎%), K (1932.1-2608.7㎎%), and Mg (800.6-1984.8㎎%). The major amino acid was glutamic acid, comprising 16.3% of total amino acids in fruit and 25.2% in pad. Dihydroflavonols were identified as (+)-trans-dihydrokaempferol and (+)-trans-dihydroquercetin. Citric acid methyl esters extracted from fruits showed inhibitory activities against monoamine oxidase-B. The presence of trimethyl citrate has been reported in other plants, but 1,3-dimethyl citrate and 1-monomethyl citrate have not been previously reported. The results of pharmacological efficacy tests, including serum biochemical and hematological parameters, autonomic nervous system, anti-inflammatory, analgestic activity, anti-diabetic activity, antithrombotic, anticoagulant, dopamine beta-hydroxylase, monoamine oxidase activity, hyperlipidemia, the respiratory system, antigastic, and anti-ulcerative actions indicate that the fruit and pad of the Opuntia ficus-indica are rich sources of food and medicinal materials.

• Fibers and Polymers
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• v.7 no.4
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• pp.404-413
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• 2006

This study examines multiple quality optimization of the injection molding for Polyether Ether Ketone (PEEK). It also looks into the dimensional deviation and strength of screws that are reduced and improved for the molding quality, respectively. This study applies the Taguchi method to cut down on the number of experiments and combines grey relational analysis to determine the optimal processing parameters for multiple quality characteristics. The quality characteristics of this experiment are the screws' outer diameter, tensile strength and twisting strength. First, one should determine the processing parameters that may affect the injection molding with the $L_{18}(2^1{\times}3^7)$ orthogonal, including mold temperature, pre-plasticity amount, injection pressure, injection speed, screw speed, packing pressure, packing time and cooling time. Then, the grey relational analysis, whose response table and response graph indicate the optimum processing parameters for multiple quality characteristics, is applied to resolve this drawback. The Taguchi method only takes a single quality characteristic into consideration. Finally, a processing parameter prediction system is established by using the back-propagation neural network. The percentage errors all fall within 2%, between the predicted values and the target values. This reveals that the prediction system established in this study produces excellent results.