• Coupled systems mechanics
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• v.8 no.3
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• pp.199-218
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• 2019

This paper studies the forced vibration of the hydro-elastic system consisting of the anisotropic (orthotropic) plate, compressible viscous fluid and rigid wall within the scope of the exact equations and relations of elastodynamics for anisotropic bodies for describing of the plate motion, and with utilizing the linearized exact Navier-Stokes equations for describing of the fluid flow. For solution of the corresponding boundary value problem it is employed time-harmonic presentation of the sought values with respect to time and the Fourier transform with respect to the space coordinate on the coordinate axis directed along the plate length. Numerical results on the pressure acting on the interface plane between the plate and fluid are presented and discussed. The main aim in this discussion is focused on the study of the influence of the plate material anisotropy on the frequency response of the mentioned pressure. In particular, it is established that under fixed values of the shear modulus of the plate material a decrease in the values of the modulus of elasticity of the plate material in the direction of plate length causes to increase of the absolute values of the interface pressure. The numerical results are presented not only for the viscous fluid case but also for the inviscid fluid case.

• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.179-186
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• 2019

The purpose of this study is to investigate the drinking culture and attitude difference by gender and grade of Korean college students. A questionnaire was conducted to analyze the characteristics and meaningful differences by two variables about drinking pattern, culture and related policies. The analysis showed that regardless of gender, far more students were against than in favor of prohibition on drinking within campus, whose legislation recently failed. Meanwhile, there was a significant difference by grade in victimization experience regarding drinking within the campus, and by gender in frequency, beverage type, volume, onset of drinking within school. There was no statistically significant gender-based difference in response to experience of damage caused by drinking, but the research results of the related papers show that the female students are more dangerous and need special attention and care. Universities should implement a professional counseling program that is customized according to gender or level of education, and managed by group. Moreover, health authorities must seek a way to lead this move, such as providing incentives to the universities, which efficiently deal with students' drinking problem. And the prohibition on drinking within campus, whose legislation recently failed should be reconsidered.

• Coupled systems mechanics
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• v.8 no.5
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• pp.393-414
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• 2019

This paper presents seismic analysis of concrete gravity dams considering soil-structure-fluid interaction. Displacement based plane strain finite element formulation is considered for the dam and foundation domain whereas pressure based finite element formulation is considered for the reservoir domain. A direct coupling method has been adopted to obtain the interaction effects among the dam, foundation and reservoir domain to obtain the dynamic responses of the dam. An efficient absorbing boundary condition has been implemented at the truncation surfaces of the foundation and reservoir domains. A parametric study has been carried out considering each domain separately and collectively based on natural frequencies, crest displacement and stress at the neck level of the dam body. The combined frequency of the entire coupled system is very less than that of the each individual sub-system. The crest displacement and neck level stresses of the dam shows prominent enhancement when coupling effect is taken into consideration. These outcomes suggest that a complete coupled analysis is necessary to obtain the actual responses of the concrete gravity dam. The developed methodology can easily be implemented in finite element code for analyzing the coupled problem to obtain the desired responses of the individual subdomains.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.605-608
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• 2009

It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sending purpose. However, The conventional spectrum estimation method, FFT(Fast Fourier Transform), called the Doppler filter bank, causes the frequency resolution problem if the dwell time is relatively short. This short acquisition time also spreads the side lobe levels of return echoes further, resulting in difficulties for the discrimination of weak target signals included in relatively strong target echoes. Therefore, in this paper, the efficient Doppler spectrum estimation methods are compared and investigated through the parameter spectrum estimation in the time domain to overcome these problems.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.9
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• pp.41-48
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• 2019

Recently as the rapid increasing of the elderly, silver housing has grown up. Though much fire evacuation and safety law, fire accident is most dangerous problem in our society. So this study is the purpose to analyze evacuation safety in urban silver housing of floor planning by corridor types using human behavior simulation. The methodology of this study is 'Literature Review' and 'Simulation'. This study has been carried out on silver housing's definition, types, fire safety theory and relation law. To proof evacuation safety, this study measured escaping time, longest distance, and bottleneck counting using human behavior simulation. This study use game engine simulation program to analyze 6 corridor types experimental model. As the result of simulation, this study compare between ASET and simulation result. The result come down to 3 part. First, double loaded corridor type is the most dangerous on urban silver housing. Second, Safe shelter's location and number cause increasing of escaping time. Lastly escaping time is influenced by behavior of agent, bottle neck strike frequency.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.1
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• pp.38-44
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• 2021

Wi-Fi provides some low-power connection solutions that other Bluetooth cannot provide, and at the same time brings many benefits. First, there is a potentially higher data rate: it can reach 230mbps. Wi-Fi coverage is also wider than competitors, and its operating frequency is also 5GHz, which is much less congested than 2.4GHz. Finally, it also supports IP networks, which is important if you want to send data to the cloud without complexity. The 802.11ac standard of the previous generation still accounts for most shipments (80.9%) and revenue (76.2%). However, there is a limit to accepting IoT devices that will continue to increase significantly in the future. To solve this problem, the new Wi-Fi 6 standard is expected to be the solution (IEEE 802.11ax) which is quickly becoming the main driving force of the wireless local area network (WLAN) market. According to IDC market research analysts, in the first quarter of 2020, independent access points (APs) supported by Wi-Fi 6 accounted for 11.8% of shipments, but 21.8% of revenue. In this paper, we have compared and analyzed the IoT connectivity, QoS, and security requirements of devices using Wi-Fi 6 network.

• Journal of Korean society of Dental Hygiene
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• v.21 no.4
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• pp.383-391
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• 2021

Objectives: Based on the 7th National Health and Nutrition Examination Survey 1,135 adults aged 19 years were selected as the final study subjects to investigate the relationship between oral health and chewing difficulty in adults. Methods: Frequency analysis, chi-square test, and logistic regression analysis were performed for general characteristics, oral health behaviors, awareness symptoms, and oral health using SPSS Program 21.0. Results: Regarding factors related to chewing difficulty, the oral health was 0.44 times lower than the average level and 0.28 times lower than the good condition. In the case of oral examination, chewing difficulty was 0.85 times lower. The speaking problem was 0.11 times lower in usually than inconvenient and 0.06 times lower in not inconvenient. In the case of un-treatment, it was 0.40 times lower than that in the case of treatment. The chewing difficulty was significantly higher by 2.09 times in the case of experience of tooth pain and 1.36 times in the case of periodontal disease. Conclusions: Based on the above results, it is thought that prevention and treatment are actively needed to identify factors of oral health to improve oral health, to solve chewing difficulty and to improve chewing function.

• CELLMED
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• v.11 no.3
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• pp.12.1-12.5
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• 2021

Gestational diabetes mellitus (GDM) has become one of the major public health problems for both mothers and children globally. Internationally, the frequency of excess weight and obesity has risen dramatically in women of childbearing age. There seems to be a greater risk of having GDM in overweight or obese women, resulting in problems during pregnancy, birth and neonatal development. Hospital management is a problem for obese pregnant females with GDM and places extra burdens on the healthcare sector. GDM can result in possible risks to the wellbeing of the mother, fetus, and infant, as well as clinically significant negative effects on the mental health of the mother. For females and their developing babies, diabetes may cause problems during pregnancy. Unsatisfactory diabetes control enhances the risk of complications and other birth related issues during pregnancy. It may also cause a woman to suffer severe complications. Numerous maternal and fetal effects are associated with GDM and multiple detection and management methods are also pursued globally in order to reduce the burden of health. An overview of gestational diabetes treatment is given in this review.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.3
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• pp.164-172
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• 2022

A HAZID is a brainstorming workshop to identify hazards in an early phase of a project. It should be flexible to capture all probable accidents allowing experienced participants to exploit their expertise and experiences. A bowtie analysis is a graphical representation of major accident hazards elaborating safety measures i.e. barriers. The result of these workshops should be documented in an organized manner to share as good as possible details of the discussion through the lifetime of the project. Currently results are documented using a three-step representation of an accident; causes, top event and consequences, which cannot capture correctly sequence of events leading to various accidents and roles of barrier between two events. Another problem is that barriers would be shown repeatedly leading to a misunderstanding that there are an enough number of safety measures. A new bowtie analysis method is proposed to describe an accident in multiple steps showing relations among causes or consequences. With causes and consequences shown in a format of a tree, the frequencies of having the top event (Fault tree analysis) and various consequences (Event tree analysis) are evaluated automatically based on the frequency of initiating causes and the probabilities of failure of barriers. It will provide a good description of the accident scenario and help the risk to be assessed transparently.

• Korean Journal of Veterinary Research
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• v.61 no.4
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• pp.40.1-40.6
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• 2021

Acid-base disorder is a common problem in veterinary emergency and critical care. Traditional methods, as well as the Stewart method based on strong ion difference concepts and the Fencl-Stewart method, can be used to analyze the underlying causes. On the other hand, there are insufficient comparative study data on these methods in cats. From 2018 to 2020, 327 acid-base analysis data were collected from 69 sick and 18 healthy cats. The three most well-known methods (traditional method, Stewart method, and Fencl-Stewart method) were used to analyze the acid-base status. The frequency of acid-base imbalances and the degree of variation according to the disease were also evaluated. In the traditional acid-base analysis, 5/69 (7.2%) cats showed a normal acid-base status, and 23.2% and 40.6% of the simple and mixed disorders, respectively. The Fencl-Stewart method showed changes in both the acidotic and alkalotic processes in 64/69 (92.8%), whereas all cats showed an abnormal status in the Fencl-Stewart method (semiquantitative approach). The frequencies of the different acid-base imbalances were identified according to the analysis method. These findings can assist in analyzing the underlying causes of acid-base imbalance and developing the appropriate treatment.