• Geomechanics and Engineering
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• v.6 no.6
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• pp.531-544
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• 2014

Studies of earthquakes over the last 50 years and the examination of dynamic soil behavior reveal that soil behavior is highly nonlinear and hysteretic even at small strains. Nonlinear behavior of soils during a seismic event has a predominant role in current site response analysis approaches. Common approaches to ground response analysis include linear, equivalent linear and nonlinear methods. These methods of ground response analysis may also be categorized into time domain and frequency domain concepts. Simplicity in developing analytical relations and accuracy in considering soils' dynamic properties dependency to loading frequency are benefits of frequency domain analysis. On the other hand, nonlinear methods are complicated and time consuming mainly because of their step by step integrations in time intervals. In part Ι of this paper, governing equations for seismic response analysis of surcharged and layered soils were developed using fundamental of wave propagation theory based on transfer function and boundary conditions. In this part, nonlinear seismic ground response is analyzed using extended HFTD method. The extended HFTD method benefits Newton-Raphson procedure which applies regular iterations and follows soils' fundamental stress-strain curve until convergence is achieved. The nonlinear HFTD approach developed here are applied to some examples presented in this part of the paper. Case studies are carried in which effects of some influencing parameters on the response are investigated. Results show that the current approach is sufficiently accurate, efficient, and fast converging. Discussions on the results obtained are presented throughout this part of the paper.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.459-467
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• 2007

The effects of turbid water on fish community was investigated in a clear reference stream (the Bongsan Steam) and a turbid stream (the Daegi Stream) located in the upstream region of the South Han River, Korea. The stress index (SI) of suspended solids (SS) were calculated during a rain event concentration by the equation SI=LN (SS${\times}$duration). EMC of SS was $1{\sim}13$ mg $L^{-1}$ in the clear stream with a mean SI of 5.2, while SS was $97{\sim}1,150$ mg $L^{-1}$ in the turbid stream with a mean SI of 10.3. Even though the number of species was not much different, the dominant species of the two steams were distinctly different. The reference stream was dominated by upstream species such as Rhynchocypris kumgangensis, Brachymystax lenok tsinlingensis, and Cottus poecilopus which are typical upstream community. Whereas the turbid streams was dominated by Rhynchocypris kumgangensis, Zacco koreanus, and Orthrias nudus which are representatives of middle reache community. Fish density was four times higher in the clear steam than the turbid stream. In the similarity analysis of fish communities the community of the turbid stream showed large dissimilarity with other communities in other streams of similar size. In conclusion, although turbidity might be at the sublethal concentration, fish communities are under stress in some turbid streams of Korea that is strong enough to induce community change. It can be an example of a chronic ecological toxicity of turbidity at the community level.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.34-34
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• 2012

Heavy storms rainfall has caused many landslides and slope failures especially in the mountainous area of the world. Landslides and slope failures are common geologic hazards and posed serious threats and globally cause billions in monetary losses and thousands of casualies each year so that studies on slope stability and its failure mechanism under rainfall are being increasing attention of these days. Rainfall-induced slope failures are generally caused by the rise in ground water level, and increase in pore water pressures and seepage forces during periods of intense rainfall. The effective stress in the soil will be decreased due to the increased pore pressure, which thus reduces the soil shear strength, eventually resulting in slope failure. During the rainfall, a wetting front goes downward into the slope, resulting in a gradual increase of the water content and a decrease of the negative pore-water pressure. This negative pore-water pressure is referred to as matric suction when referenced to the pore air pressure that contributes to the stability of unsaturated soil slopes. Therefore, the importance is the study of saturated unsaturated soil behaviors in evaluation of slope stability under heavy rainfall condition. In an actual field, a series of failures may occur in a slope due to a rainfall event. So, this study attempts to develop a numerical model to investigate this failure mechanism. A two-dimensional seepage flow model coupled with a one-dimensional surface flow and erosion/deposition model is used for seepage analysis. It is necessary to identify either there is surface runoff produced or not in a soil slope during a rainfall event, while analyzing the seepage and stability of such slopes. Runoff produced by rainfall may result erosion/deposition process on the surface of the slope. The depth of runoff has vital role in the seepage process within the soil domain so that surface flow and erosion/deposition model computes the surface water head of the runoff produced by the rainfall, and erosion/deposition on the surface of the model slope. Pore water pressure and moisture content data obtained by the seepage flow model are then used to analyze the stability of the slope. Spencer method of slope stability analysis is incorporated into dynamic programming to locate the critical slip surface of a general slope.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.186-190
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• 2014

Nuclear Power Plants require the control ability of chemical condition (pH) because pH control during transient accident such as LOCA makes an able the fission product removal capability to be maintained, stress corrosion cracking of stainless steel equipment to be prevented and the production of hydrogen by aluminum and zinc to be minimized. An NPP is designed to control the pH of containment spray and sump coolant using the spray additives 30% NaOH in the event of loss of coolant accident. In this paper, the pH of sump coolant of an NPP during LOCA was analyzed and the fission products removal constant and decontamination factor were calculated according to Standard Review Plan 6.5.2 related to spray chemical conditions of pH. The calculated pH value of recirculation mode using the computer code corresponds to 8.09~9.67, which meets the chemical environment regulation requirements. The fission product removal capability caused by containment spray system is performed to provide input to radiation analysis.

• Geophysics and Geophysical Exploration
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• v.13 no.2
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• pp.137-143
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• 2010

An earthquake with local magnitude $(M_L)$ 3.7 on December 9, 2000 occurred offshore Yeongdeok area, South Korea. In case of applying Chang and Baag (2006) crustal velocity model, the epicenter is $36.4462^{\circ}N\;and\;129.9789^{\circ}E$, which belongs to the inside of the Korean Peninsula Continental Shelf. Although we use the modified model reducing crustal thickness of Chang and Baag (2006) model by 5 km considering the transition from continental crust to oceanic crust in the East Sea, the epicenter was little changed. We carried out the waveform inversion analysis to estimate focal depth and focal mechanism of this event. The focal depth is estimated to be 11 ~ 12 km. The seismic moment is estimated to be $1.0{\times}10^{15}N{\cdot}m$, and this value corresponds to the moment magnitude $(M_W)$ 3.9. The offshore Yeongdeok event including May 29, 2004 offshore Uljin one show typical thrust faulting, and the direction of P-axis is ESE-WNW. The moment magnitude estimated by the spectral analysis is 4.0, which is similar to that by the waveform inversion analysis. Average stress drop is estimated to be 3.4 MPa.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.325-330
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• 2011

RCP(Reactor coolant pump) must be designed to preserve it's functions on normal or abnormal environments and seismic event same as operating basis earthquake(OBE) and safe shutdown earthquake(SSE). Generally, there are static and dynamic analytical method which can be applied by a floor response spectrum or time history analysis for the seismic qualification. Initially, It was accomplished a detailed structural FE-model for finite element analysis on the bases of 3-dimensional solid model which was made by the RCP drawing. As the result of dynamic characteristic using the detailed FE-model, it's shown about 12Hz natural frequency of 1st bending mode shape and maximum displacement has 11mm with the structural bending by single-point response spectrum(SPRS) method at all elevation. But maximum displacement has 7.6mm by multi-point response spectrum(MPRS) method which was applied to the three floor response spectrum at each elevation. Therefore, On a large heighten structures as RCP, The application by SPRS method causes to be more conservative results. Finally, A simpled equivalent beam model which was developed by use of iteration of detailed FE-model is shown the result more similar with those of natural frequencies and SPRS analysis. And maximum equivalent stress and displacement of the simpled beam has verified with 180MPa and 7.1mm each at 15sec as results by SSE time history method.

• Health Policy and Management
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• v.34 no.2
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• pp.129-140
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• 2024

Background: The mental health issues caused by trauma can manifest differently depending on the characteristics of the traumatic event. Particularly, individuals who have experienced sexual trauma are known to have more negative mental health outcomes compared to those who have experienced non-sexual trauma. The mental health issues of individuals who have experienced sexual trauma are severe, and new forms of threats, such as digital sexual crimes, are emerging. This study aimed to investigate whether the type of traumatic event, particularly focusing on sexual trauma events, contributes to differences in mental health outcomes and to identify factors influencing suicidal ideation and potential post-traumatic stress disorder (PTSD) risk. Methods: Based on an online survey conducted nationwide among adults aged 20 to 50, participants were categorized based on the type of trauma they experienced (sexual trauma events and non-sexual trauma events). The study conducted propensity score matching (PSM) using demographic factors (sex, age group, subjective economic status, and marital status) and resilience protective factors (cognition of recoverability, social support, and protection experiences in childhood) as control variables, excluding the experience of sexual trauma events, to investigate their potential impact on mental health (suicidal ideation and potential PTSD risk). Subsequently, binary logistic regression analysis was conducted to identify factors influencing mental health. Results: Even after PSM, individuals who experienced sexual trauma exhibited more negative outcomes in terms of suicidal ideation and potential PTSD risk compared to those who experienced non-sexual trauma. The results of binary logistic regression analysis showed that sexual trauma survivors were 1.9 times more likely to have suicidal thoughts (odds ratio [OR], 1.911) and 2.5 times more likely to have a potential PTSD risk (OR, 2.472). Furthermore, as resilience protective factors became more negative, the likelihood of suicidal ideation and potential PTSD risk increased. Conclusion: This study emphasizes the importance of understanding and supporting individuals who have experienced sexual trauma, highlighting the necessity for strategies aimed at mitigating suicidal ideation and potential PTSD risk among sexual trauma survivors, while also facilitating recovery through the promotion of resilience protective factors.

• Journal of Korean Academy of Nursing Administration
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• v.4 no.1
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• pp.215-228
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• 1998

The purpose of this study is analysis of 52 dissertations on assertiveness training which presented from 1982 to 1997 in Korea. It was diversified the research purpose to by 1) time of publication or presentation 2) research design, characteristics of subjects used in each study 3) related concepts, the effects of nursing interventions according to related concepts 4) the effects of nursing interventions according to the subjects 5) the effects of nursing interventions according to the frequency and the period of assertiveness training 6) the effects of nursing interventions according to the group size. 7) the effects of nursing interventions according to the necessary time per round. Findings obtained in the study were as follows : 1. At the point of the numbers of studies presented by year, the number of the studies tend to increase, especially the most plentiful papers were presented during five years from 1991 to 1995. 2. Research design of the studies belong to experimental research. The subjects of research consists of 5 Nursing related subjects and 47 Non-nursing related subjects so that Non-nursing related subjects contain much large proportion. 3. When studies were classified by the related concepts, they were classified that 17 studies were by assertiveness & assertive behaviour, 15 ones anxiety, 9 ones self & ego, 7 ones depression. It can be inferred that studies related to assertive behaviour, self & ego, sociality and power of learning were increasing. Otherwise, studies related to anxiety, depression, aggression, shyness and anguish were decreasing. 4. At the point of the nursing intervention effect by the subjects, the concepts of assertive behavior, feeling of self-respect and sociality were increasing, but the concepts of conflict and interpersonal stress were decreasing and the concepts of anxiety and sociality were ineffective in the subjects related Nursing. On the contrary, the concepts of assertive behavior, sociality and personalty were increasing, but the concepts of anxiety, depression, aggression, shyness, self-estranged feeling were decreasing and the concepts of assertive behavior, aggression, personalty, power of learning, anxiety, self-concepts and self-expression were ineffective in the subjects related Non-Nursing. 5. 18 studies can be found, which investigated 10 times for 5 weeks from the point of the nursing intervention effect by the times and the period of assertiveness training. In case of over 5 times of assertiveness training, assertiveness, assertive behavior and personality(tranquility, depression) increased. In 6 times, feeling of self-respect & egorespect increased but depression, interpersonal stress and anxiety decreased. In over 10 times, shyness, shame and feeling of self-estrangement decreased. In over 12 times, interpersonal anxiety decreased. 6. In the event of nursing intervention effect by the size of the group, it was greatest within 10 persons in 21 studies. In case of within 10 to 20, only feeling of self-expression were ineffective. Particularly, in case of over 31 persons, there were no ineffective concepts. 7. At the viewpoint of nursing intervention effect by the necessary time of one time, it was greatest within 1 to 2 hours in 32 studies. In case of within 1hour, aggression, power of learning and assertiveness were ineffective. In case of within 1 to 2 hours, assertive behavior, self-expression, personality and anxiety were ineffective. Particularly, in case of within 2 to 3 hours, there were no ineffective concepts.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.208-216
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• 2016

Objectives : According to the recent Korean National Police Agency report, rape victims were 17.1%, but sexual molestation victims were more than the rape victims by 78.0%. Despite many international reports about the occurrence of severe psychiatric symptoms in sexual molestation victims, there is no domestic research. Therefore in this study, we investigated psychiatric symptoms of sexual molestation victims, and we also compared it with psychiatric symptoms in rape victims. Methods : 58 women who visited Busan Smile Center within 3months after sexual violence were the study subjects. Questionnaire about sociodemographic and sexual violence related characteristics were retrospectively investigated. Of the psychiatric symptoms, Beck Depression Inventory(BDI), Beck Anxiety Inventory(BAI) for severity of depression and anxiety, and Impact of Event Scale-Revised(IES-R) to check the presence of posttraumatic stress disorder(PTSD) symptoms were used. Results : Of 58 sexual violence victims, sexual molestation victims were 36(62.1%) and rape victims were 22(37.9%). In sexual molestation victims, 80.6% had more than moderate severity of depression, 83.3% had more than moderate severity of anxiety, and 94.4% had significant scores at PTSD screening test. Compared with rape victims' psychiatric symptoms(each 95.5%, 95.5%, 95.5%) there were no significant difference. Conclusions : The majority of sexual molestation victims were also accompanied by depression, anxiety and PTSD symptoms as rape victims. There results suggest that appropriate assessment and early treatment for psychiatric symptom must be made in the early stage of injury in sexual molestation victims.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2799-2805
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• 2024

Energy-resolved neutron imaging is an effective way to investigate the internal structure and residual stress of materials. Different sample sizes have varying requirements for the detector's imaging field of view (FOV) and spatial resolution. Therefore, a dual-mode energy-resolved neutron imaging detector was developed, which mainly consisted of a neutron scintillator screen, a mirror, imaging lenses, and a time-stamping optical fast camera. This detector could operate in a large FOV mode or a high spatial resolution mode. To evaluate the performance of the detector, the neutron wavelength spectra and the multiple spatial resolution tests were conducted at CSNS. The results demonstrated that the detector accurately measured the neutron wavelength spectra selected by a bandwidth chopper. The best spatial resolution was about 20 ㎛ in high spatial resolution mode after event reconstruction, and a FOV of 45.0 mm × 45.0 mm was obtained in large FOV mode. The feasibility was validated to change the spatial resolution and FOV by replacing the scintillator screen and adjusting the lens magnification.