• Safety and Health at Work
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• v.14 no.4
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• pp.457-466
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• 2023

Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28℃, and the weight, inhalation resistance (R_f), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the R_f and 10-200 nm total aerosol penetration (P_t) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the R_f, P_t, and absorbed water all increased significantly. Conclusions: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.331-339
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• 2022

The global process of transition from industrial to information society, as well as socio-economic changes taking place in Ukraine, require significant changes in many areas of state activity. It is especially connected with the reforms in the sphere of education. Today, national programs provide for the development of education on the basis of new progressive concepts, the introduction of the educational process of new pedagogical technologies and scientific achievements, the creation of a new system of information education, entrance of Ukaine into the transcontinental computer information system. Information technologies are qualitatively changing the key resources of development: this is no longer a space with fixed production, but primarily mobile finance and intelligence. They have a direct impact on the formation of personal growth, professional content and self-organization, emotional and psychological maturity and consciousness, and so on. One of the main factors in ensuring the stability and social education of the country's citizens is the culture of security, the formation and development of which is an urgent problem today. Comprehensive and systematic development of security culture will significantly increase the readiness of the population, the level of environmental, labor and patriotic education, reduce human losses, material damage from emergencies. Ecological education can be carried out more successfully only gradually and in accordance with the socio-psychological periods of one's development: kindergarten - school - college - university. The creation of such a system of environmental education should be enshrined as the basis of state environmental policy as a constitutional norm with the usage of information technology. Graduates of universities, who are the future of our country, after mastering the skills of basic environmental education must have a high level of environmental culture, which is, in turn, part of general human culture, and investigate environmental issues from the standpoint of their profession. It is known that with the help of environmental education the collective intelligence of society is formed, which can predict human activities and processes occurring in nature, and in some way to help with the elimination of crises. It is through environmental education that another system of human values is being formed, which places great emphasis on intangible wealth and solidarity, and great responsibility of humanity for the ecological state of the native country; provides a higher standard of living as a result of sustainable development, through the introduction of information technology in this system. To improve the quality of life, we need better knowledge, which must be implemented through information technology at the international level.

• ETRI Journal
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• v.40 no.4
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• pp.511-521
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• 2018

The ability to realize human-motion imitation using robots is closely related to developments in the field of artificial intelligence. However, it is not easy to imitate human motions entirely owing to the physical differences between the human body and robots. In this paper, we propose a work chain-based inverse kinematics to enable a robot to imitate the human motion of upper limbs in real time. Two work chains are built on each arm to ensure that there is motion similarity, such as the end effector trajectory and the joint-angle configuration. In addition, a two-phase filter is used to remove the interference and noise, together with a self-collision avoidance scheme to maintain the stability of the robot during the imitation. Experimental results verify the effectiveness of our solution on the humanoid robot Nao-H25 in terms of accuracy and real-time performance.

• Journal of Korean Association for Spatial Structures
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• v.18 no.3
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• pp.83-91
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• 2018

In this study, we investigated the dynamic stability of the system and the semi-analytical solution of the shallow arch. The governing equation for the primary symmetric mode of the arch under external load was derived and expressed simply by using parameters. The semi-analytical solution of the equation was obtained using the Taylor series and the stability of the system for the constant load was analyzed. As a result, we can classify equilibrium points by root of equilibrium equation, and classified stable, asymptotical stable and unstable resigns of equilibrium path. We observed stable points and attractors that appeared differently depending on the shape parameter h, and we can see the points where dynamic buckling occurs. Dynamic buckling of arches with initial condition did not occur in low shape parameter, and sensitive range of critical boundary was observed in low damping constants.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.711-717
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• 2016

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

• Journal of The Korean Association of Information Education
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• v.25 no.3
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• pp.471-481
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• 2021

The purpose of this study is to analyze the effectiveness of AI convergence education program. To this end, the "Elementary Science AI Convergence Education Program for Machine Learning" developed in previous research were taught to elementary school students in the fourth to sixth grades in eight times. The quantitative changes of each factor were analyzed by R program, and the effectiveness of education was analyzed by Pearson correlation and paired samples t-test. As a result, there is a deep correlation between "Attitude to AI technology, Scientific preference and STEAM Literacy" and technical average has improved in many factors. Therefore, AI convergence education program is meaningful in terms of education, and if AI education and AI convergence education are implemented into the primary formal education curriculum, they will have a positive effect.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1109-1114
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• 2015

This paper presents an improved learning-based visual inspection method for auto parts inspection in severe lighting changes. Automobile sunroof frames are produced automatically by robots in most production lines. In the sunroof frame manufacturing process, there is a quality problem with some parts such as volts are missed. Instead of manual sampling inspection using some mechanical jig instruments, a learning-based machine vision system was proposed in the previous research[1]. But, in applying the actual sunroof frame production process, the inspection accuracy of the proposed vision system is much lowered because of severe illumination changes. In order to overcome this capricious environment, some selective feature vectors and cascade classifiers are used for each auto parts. And we are able to improve the inspection accuracy through the re-learning concept for the misclassified data. The effectiveness of the proposed visual inspection method is verified through sufficient experiments in a real sunroof production line.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4510-4526
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• 2017

Most available methods of facial gender recognition work well under a constrained situation, but the performances of these methods have decreased significantly when they are implemented under unconstrained environments. In this paper, a method via low-rank and collaborative representation is proposed for facial gender recognition in the wild. Firstly, the low-rank decomposition is applied to the face image to minimize the negative effect caused by various corruptions and dynamical illuminations in an unconstrained environment. And, we employ the collaborative representation to be as the classifier, which using the much weaker $l_2-norm$ sparsity constraint to achieve similar classification results but with significantly lower complexity. The proposed method combines the low-rank and collaborative representation to an organic whole to solve the task of facial gender recognition under unconstrained environments. Extensive experiments on three benchmarks including AR, CAS-PERL and YouTube are conducted to show the effectiveness of the proposed method. Compared with several state-of-the-art algorithms, our method has overwhelming superiority in the aspects of accuracy and robustness.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.599-609
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• 2000

In this paper, sub-harmonically pumped single balanced resistive mixers are presented . Frequency bandwidth is selected for a Ku-band, which is 11.75-12.25GHz for RF, 5.375∼5.625 GHz for LO, and 1 GHz for IF signals. A rat-race hybrid is designed for the accomplishment of single balanced type. A low pass filter (LPF) with photonic band gap(PBG) structure is used for good conversion loss and unwanted harmonics suppression. Two types of mixers are suggested, which are one with no gate bias for no DC power consumption and the other with the IF amplifier for conversion gain. When a LO signal with the power of 6 dBm at 5.5 GHz is injected, a conversion loss of 12.17dB and a conversion gain of 7.83 dB are obtained for each mixer. For the both mixers , LO to RF isolation of 20 dB and LO to IF isolation of 60dB are obtained. With the RF power of -30dBm to -3dBm, the mixer shows linear characteristics region of IF. this mixer can be applied for Ku-band and other microwave communication systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.249-254
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• 2018

We researched about a bulk metallic glass system as an additive to an Ag paste for high temperature thermoelectric modules. Bulk metallic glass (BMG) ribbons were produced by using a rapid solidification process (RSP) under a cooling rate condition higher than $10^{\circ}C/sec$. We investigated BMG characteristics of the ribbons by means of x-ray diffraction (XRD) and differential scanning calorimetry (DSC) in order to evaluate the glass transition temperature ($T_g$) and the recrystallization temperature ($T_x$) lower than $400^{\circ}C$. A milling process was also developed to apply the BMG ribbons to a commercial Al paste as an additive for lower sintering temperature.