• Journal of Power Electronics
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• v.19 no.1
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• pp.244-253
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• 2019

Finite control set model-predictive control (FCS-MPC) has received increasing attentions due to its outstanding dynamic performance. It is being widely used in power converters and multilevel inverters. However, FCS-MPC requires a lot of calculations, especially for multilevel-cascaded H-bridge (CHB) static synchronous compensators (STATCOMs), since it has to take account of all the feasible voltage vectors of inverters. Hence, an improved five-segment space vector pulse width modulation (SVPWM) method based on the non-orthogonal static reference frames is proposed. The proposed SVPWM method has a lower number of switching states and requires fewer computations than the conventional method. As a result, it makes FCS-MPC more efficient for multilevel cascaded H-bridge STATCOMs. The partial cost function is adopted to sequentially solve for the reference current and capacitor voltage. The proposed FCS-MPC method can reduce the calculation burden of the FCS-MPC strategy, and reduce both the switching frequency and power losses. Simulation and experimental results validate the excellent performance of the proposed method when compared with the conventional approach.

• ETRI Journal
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• v.44 no.3
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• pp.426-437
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• 2022

To understand the multilateral characteristics of human behavior and physiological markers related to physical, emotional, and environmental states, extensive lifelog data collection in a real-world environment is essential. Here, we propose a data collection method using multimodal mobile sensing and present a long-term dataset from 22 subjects and 616 days of experimental sessions. The dataset contains over 10 000 hours of data, including physiological, data such as photoplethysmography, electrodermal activity, and skin temperature in addition to the multivariate behavioral data. Furthermore, it consists of 10 372 user labels with emotional states and 590 days of sleep quality data. To demonstrate feasibility, human activity recognition was applied on the sensor data using a convolutional neural network-based deep learning model with 92.78% recognition accuracy. From the activity recognition result, we extracted the daily behavior pattern and discovered five representative models by applying spectral clustering. This demonstrates that the dataset contributed toward understanding human behavior using multimodal data accumulated throughout daily lives under natural conditions.

• New & Renewable Energy
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• v.18 no.3
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• pp.72-84
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• 2022

As the threat of climate change escalates, 'net-zero' has become a priority for the international community, and the use of new and renewable energy sources is expected to play a significant role in reaching international carbon neutrality. Here, we evaluate technological competitiveness in terms of implementation and technology by analyzing scientific literature and patents in the new and renewable energy fields of five major countries. For the past 10 years (2009-2019), the most active areas of new and renewable energy research and development have been solar power, wind power, waste, and fuel cells. China is the forerunner in implementation, whereas the United States has the most advanced technology. Portfolio analysis revealed that Korea's fuel cell, the United States' bioenergy, China's waste, Japan's solar and fuel cell, and the European Union's wind power have shown to be in Star Field respectively. Technological competitiveness analysis found that Korea is lagging behind other countries in the new and renewable energy sector, and needs to set a new direction for future carbon-neutral research and development, investment, and policy.

• Composites Research
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• v.36 no.1
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• pp.42-47
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• 2023

In this paper, we present a fatigue life prediction methodology using multiple S-N curves according to the different stress states of laminated composites. The stress states of the plies of the laminated composites are classified into five modes: longitudinal tension or compression and transverse tension or compression, and shear according to the maximum stress criterion and Puck's criterion with a scaling factor K. This methodology has advantages in computational cost, and it can also consider microstructural characteristics of the composites by applying different S-N curves. The S-N curves for the fatigue analysis are obtained by experimental fatigue test. The proposed methodol is implemented into commercial software, ABAQUS user material subroutine and therefore, the fatigue analysis is conducted using the structural analysis results. The finite element (FE) simulation results are presented for unidirectional composites with and without open-hole. The FE simulation results show that the stress condition is different depending on the fiber orientation of the unidirectional composite, so the fatigue life is calculated with different S-N curves.

• Journal of Information Science Theory and Practice
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• v.11 no.4
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• pp.1-13
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• 2023

Being one of the first and hardest hit countries by the coronavirus, Iran still continues to preserve its place among nations with the highest rates of infection and COVID-19 related deaths. While on the surface, such worrying status evinces the failure of the authorities in handling the crisis, at deeper levels, it points to the fundamentalist nature of the government and political system of the country. In this view, the current devastating condition in Iran is a clear indication of the all-out influence of the Islamic regime's ideologies on officials' decision-making and their political agendas throughout the pandemic. Accordingly, the staterun mainstream media, as the most preeminent institution of power, have been incessantly engaged in disseminating a series of ideology-laden information around the issues concerning the coronavirus, and in line with the developing political discourses during pandemic. Far from being based on factual accounts or scientific facts, these disseminated messages inevitably grew into a source of disinformation, ultimately resulting in overall public confusion and skepticism. Through examining the data gathered from some of the most prominent online news agencies run by the government, this study identifies five major discursive trends through which the mainstream media propagated ambiguous and manipulative information about COVID-19. These findings are then explained in the light of media system dependency theory, leading to the argument that within autocratic nation-states, public reliance on media during a national/global crisis brings about new opportunities for state exploitation, and further distressing consequences for the people.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.107-116
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• 1997

In order to achieve optimal reproductive performance, reliable morphological and physiological basic data on the reproductive organs are desirable. Adult male Korean ring-necked pheasant in inactive(mid of January) and active state (end of April) were used in this study. In addition, five active state pheasants were received a single dose of 60Co-ray 500 rads each to damage the testes. The objective of this study was to investigate the distribution pattern of protein gene product (PGP) 9.5 and ${\alpha}$-tubulin in the pheasant testes of the active, inactive and ${\gamma}$-ray irradiated active states. The results obtained were summarized as follows 1. The seminiferous tubules collected in inactive states( mid of Jan) showed narrow lumen, and the spermatogonia and the Sertoli cell were well preserved. The PGP 9.5 immunoreactivity of these tubules showed a positive reaction in paranucleus area of the spermatogonia, and a positive reaction in a small number of the Leydig cells in the interstitium of the seminiferous tubules. 2. The seminiferous tubules were dilated in active state(end of April) as compared with the inactive state. The PGP 9.5 reactivity in these tubules showed a positive reaction in many Leydig cells in the interstitium of the seminiferous tubules, and the testes of ${\gamma}$-ray irradiated group showed partially weak reaction in the interstitium of the seminiferous tubules. 3. The ${\alpha}$-tubulin reactivity in the seminiferous tubules of the inactive testes was strongly positive in the cytoplasmic process of the Sertoli cell from the basal stem region to the apical ex-tension. From the broad part of the stem region to the luminal space, the active testes showed a strong positive reaction. The ${\gamma}$-ray irradiated groups showed diminished reaction in the basal region.

• Journal of Korean Academy of Nursing
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• v.30 no.1
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• pp.171-182
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• 2000

This study was performed to investigate the effect of kangaroo care on body weight, physiological responses and behavioral states in premature infants. The subjects were 32 premature infants, fifteen for the kangaroo care group and seventeen for the control group, who hospitalized in a neonatal intensive care unit at a university-affiliated hospital. The kangaroo care was applied 8 times during the twenty five days with 40 minutes for each session. The kangaroo care provides the skin-to-skin contact during which a premature infant wearing a diaper and a hat is placed on its mother's chest. As for the measures, body weight was measured everyday. The levels of epinephrine, norepinephrine and 17-OHCS were measured twice, before beginning the first intervention and after finishing the last intervention. While each session of the care is undergoing, such physiological responses were measured periodically as heart rate, respiration rate, oxygen saturation, core temperature and skin temperature. The results were as follows : 1. The weight gain was significantly greater in the kangaroo care group than that in the control group during the period of performing the kangaroo care. 2. No significant difference was revealed between the two groups in heart rate, respiration rate, oxygen saturation and core temperature. The kangaroo care group also showed significant increases in the skin temperature. 3. The differences in the levels of epinephrine, norepinephrine and 17-OHCS were not significant between the kangaroo care and the control groups. The level of norepinephrine in the two groups was significantly increased over time. 4. Sleep pattern changed significantly in the kangaroo group from a very restless sleep to a very quiet sleep. These results suggest that kangaroo care is an effective nursing intervention for premature infants in gaining weight, achieving stable physiological responses and facilitating a quiet sleep.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.1-14
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• 2014

Timber harvest in natural forests and its implications on carbon sequestration were investigated in the Southwestern Nigeria. Data on timber harvest from forest estates for a 3-year period were collected from the official record of States' Forestry Department. The data registered the species, volume and number of timbers exploited during the study period. The data were analyzed accordingly for rate of timber harvest and carbon value of the exploited timbers using existing biomass functions. Values were compared for significant differences among states using one way analysis of variance. The results showed that the most exploited logs, in terms of volume and number of trees, have the highest amount of carbon removal. There was a variation in type of timber species being exploited from each state. The total number of harvested trees from Oyo, Ondo, Ogun, Ekiti and Osun were estimated at 100,205; 111,789; 753; 15,884 and 18,153 respectively. Total quantity of carbon removed for the 3-year period stood at 2.3 million metric tons, and this translated to 8.4 million metric tons of $CO_2$. The annual carbon and $CO_2$ removal therefore were estimated at 760,120.73 tons and 2.8 million tons/ year respectively. There were significant differences (p<0.05) in the amount of $CO_2$ removed from the five states. Based on our result, we inferred that there is increasing pressure on economic tree species and it is plausible that they are becoming scarce from the forests in Southwestern Nigeria.. If the present rate of log removal is not controlled, forests could become carbon source rather than carbon sink and the on biological conservation, wood availability and climate change may turn out grave. For the forest to perform its environmental role as carbon sink, urgent conservation measures and logging policies are needed to be put in place.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.149-155
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• 2018

The purpose of this study is to create a program that will revitalize as an autonomous person through dialogue training that integrates reason and emotion when the personality formed as a child does not help life and growth of reality. The research method is to analyze the current personality as five ego states and find a way to correct or complement the result. Study results found a way to complement the external ego states shown in the state to self-activation techniques, The inner part is to achieve autonomy through the change of Trinity, the ultimate goal of change of Transactional Analysis(TA) namely, the change of three abilities: self-awareness, spontaneity, and intimacy. This is the ability to use all the resources of an individual to solve problems, or to make recovery look real.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1835-1844
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• 2007

Recently there have been some positive evidences on the effects of learning in a virtual environment. However, most of these educational VR systems were not deeply considered in the design of drawing a learner's attention on lesson contents, which would help enhance retained memory. Hence, a study was conducted to measure 17 subjects' attention states using EEC, ECG, GSR, and eye-tracking and their behaviors while they were given guided search task or exploration task in a virtual environment consisting of five major events. It also analyzed the subject's remembered items after their VR experiences using a surrey. This paper Int describes an overview of the ocean virtual environment used in this study, and it then explains the experimental design, apparatus, and method. It will also discuss the results by a detail analysis (in a whole VR session as well as event-related 10-second 33 sub-sessions) with the subjects' attention states and their retained memory after the learning.