• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.908-908
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• 2012

국내 기후 특성상 하절기에 집중되는 강우로 인해 댐의 건설을 홍수조절, 용수확보 및 전력생산 등의 목적에 있어서 불가피하다. 이와 같은 저수지와 하류하천은 댐 수문 개폐에 따라 흐름변화로 인하여 수체의 거동 및 수질 변화가 발생하며, 일반적인 하천과는 다른 특성을 지니게 된다. 또한 수심이 깊은 저수지의 경우에는 흐름방향과 더불어 수심 방향의 특성도 중요하며, 수리 및 수질 모형의 연계를 통한 3차원적인 해석을 필요로 한다. 유역 내 지상 또는 대기에서 발생한 모든 오염물질은 강우에 의해 하천과 호수와 같은 수체로 유입되며, 강우가 발생했을 때 유역의 토지피복 상태와 수리, 지형, 강우강도, 토양의 특성에 의해 하천으로 유입되는 오염물질의 농도와 부하특성이 달라진다. 비점오염물질의 축적이 가능한 호수나 저수지에서는 비점오염원의 유입이 더 큰 문제가 되며, 유량이 극히 미미한 하천의 경우에는 강우초기에 일시에 집중적으로 유입되는 초기 오염 부하량이 문제가 된다. 강우유출수의 하천 유입은 강우 현상과 밀접한 관계를 맺고 있으므로 그 제어가 쉽지 않다. 이러므로 이를 총괄하는 유역통합관리기술이 필요로 하며, 기존의 유역통합관리기술은 댐 상류유역을 중심으로 개발되고 있으며, 댐 상류유역과 저수지, 하류하천으로 구분되어 연구되어 왔다. 또한 각각의 모형이 개별적으로 적용되어 통합적인 평가시스템이 표준화되지 않은 관계로 댐 상하류 모니터링 자료가 연계된 실무 적용이 이루어지지 않고 있다. 따라서 하천 수리 수문학적 역학구조를 이해하고 그 특성에 적합하게 평가할 수 있는 표준화된 시스템이 구축되어야 한다. 또한 효과적인 유역통합관리를 위해서는 하천의 현재 뿐만 아니라 장래에 대한 예측부분도 포함되어야 한다. 본 연구에서는 댐 유역에서의 유출과 수질 변화를 모의하고 이를 이용하여 저수지 내에서의 오염물질 거동에 대해서 해석하였다. 또한 기후변화에 따른 유역, 저수지 및 하천에 미치는 영향을 고려하기 위하여 고해상도 지역기후전망 모의자료를 이용하여 수문학적 스케일로 통계적 상세화한 후 지역별 상세수문시나리오를 생산하여 미래 예측에 활용하였다. 기후변화 시나리오의 상세화를 통한 상세지역의 기후를 예측하고, 예측된 기상자료를 이용하여 유역모델을 모의하여 미래의 유출 및 수질 변화를 파악할 수 있는 기술 개발로 인해 저수지의 운영에 도움을 주고, 주수지의 치수증대 사업 등 유출의 변화에 따른 하류하천 변화를 파악할 수 있고, 기후변화에 따른 하류하천에 대한 홍수기 때 치수, 이수 및 방재에 대하여 기초자료를 제공할 수 있을 것으로 판단된다.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.186-193
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• 2014

This study aimed to analyze spatio-temporal trends of phenological characteristics in South Korea by using MODIS EVI. For the phenology analysis, we had applied double logistic function to MODIS time-series data. Our results showed that starting date of phenology seems to have a tendency along with latitudinal trends. Starting date of phenology of Jeju Island and Mt. Sobeak went back for 0.38, 0.174 days per year, respectively whereas, Mt. Jiri and Mt. Seolak went forward for 0.32 days, 0.239 days and 0.119 days, respectively. Our results exhibited the fluctuation of plant phonological season rather than the change of phonological timing and season. Starting date of plant phenology by spatial distribution revealed tendency that starting date of mountain area was late, and basin and south foot of mountain was fast. In urban ares such as Seoul metropolitan, Masan, Changwon, Milyang, Daegu and Jeju, the phonological starting date went forward quickly. Pheonoligcal attributes such as starting date and leaf fall in urban areas likely being affected from heat island effect and related warming. Our study expressed that local and regional monitoring on phonological events and changes in Korea would be possible through MODIS data.

• Journal of Korean Academy of Nursing
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• v.47 no.1
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• pp.71-85
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• 2017

Purpose: The purpose of this study was to develop a deeper understanding of the experience of mothers caring for children with epilepsy. Methods: Data were collected through individual in-depth interviews and observation from 12 mothers of children with epilepsy. Data were collected from December, 2014 to February, 2015 and analyzed using van Manen's hermeneutic phenomenological methodology to identify essential themes of their experience. Results: The essential themes that fit into the context of the 4-existential grounds of time, body, other people, and space were: Lived time-ongoing influence of the past, living in insecure present, fearful future with no answer; Lived body-bonded body, burned out state; Lived other-burden but also support, shrunken down; Lived space-narrowed range of activity, widened horizon. Conclusion: The findings in this study show in-depth understanding of the hardships of mothers who are caring for children with epilepsy. The beauty and greatness of these mothers are revealed through the analysis of various phenomenological materials such as literary and artistic work reflecting socio-cultural context, as well as vivid care experiences of mothers of children with epilepsy. This will be helpful in increasing understanding of the nature of caregivers' experience for medical professionals dealing with patients and caregivers. Also it helps to improve the understanding of the disease among the general public, followed by a more warming and caring attitude towards patients and family members. Finally, it will enhance psychological well-being and overall quality of life of the epileptic children and their families.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.849-863
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• 1992

A very simple and computationally efficient numerical method is developed for the free vibration of isotropic and orthotropic composite triangular plates. A set of two-dimensional simple series functions is used as an admissible displacement functions in the Rayleigh-Ritz method to obtain the natural frequencies, nodal patterns and mode shapes for the plates. From the prescribed starting function satisfying only the geometric boundary conditions, the higher terms in the series functions are constructed with adding order of polynominal. Natural frequencies, nodal patterns and mode shapes are obtained for right triangular plates with three different support conditions. The obtained numerical results are presented, and the isotropic and some orthotropic cases are verified with other numerical methods in the liternature.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1074-1083
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• 2010

Recently sloshing that fluid in fuel tank is undulating by the external force during motion of automobile, ship and aircraft is greatly affecting by damaging the inside of structure. It's most important to precisely analyze the behavior of fluid by computational fluid dynamics for minimizing the effect of sloshing for the loaded fuel. This study characterized volume of fluid and pressure according to the length and number of vertical baffle and horizontal baffle in fuel tank for Kia Frontier cargo and analyzed for reduction of sloshing during driving on corner and hill by using ADINA-CFD. As a result of analysis, the optimum length for sloshing reduction shows 0.19 m for vertical baffle and 0.08 m for horizontal baffle. And it shows that vertical baffle is better for the reduction effect of sloshing during driving on corners, on the other hand, horizontal baffle is effective and stable during driving on hills.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.61-72
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• 1997

With increasing activities for groundwater withdrawal and for the construction of underground cavern in the coastal areas, the seaward flow of groundwater has been disturbed or even reversed, resulting in seawater intrusion in aquifers. This phenomenon would be attributed to the freshwater contamination and the corrosion of steel materials. The hydrogeological and geochemical investigations have performed to characterize the seawater intrusion into the underground caverns located in the coastal area. Assumimg the inland aquifer as unconfined one, we have found out that the theoretical interface of freshwater-seawater is far different from the pathways identified. In the study site, the main pathways of seawater intrusion into the underground cavern are characterized as the sub-horizontal fractures (zones). The seawater intrusion in granitic terrane would depend mainly on the characteristics of conductive fracture system developed along the coastal area.

• Journal of Korean Academy of Nursing
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• v.47 no.3
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• pp.367-379
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• 2017

Purpose: This study aimed to understand and describe the caring experiences of spouses of elderly people with dementia. Methods: The hermeneutic phenomenological method was used and participants were 12 spouses aged 65 and over who were taking care of their husbands or wives with dementia at home. Data were collected from individual in-depth interviews on participants' actual caring experiences. Additionally, novels, movies, and memoirs on elderly couples with partner who had dementia were included as data for the analysis. The qualitative data analysis software program was used to manage and process the collected qualitative data. Data were analyzed using hermeneutic phenomenological analysis based on four fundamental existentials including lived body, lived space, lived time, and lived others. Results: Five essential themes emerged from the analysis: 1) body moving like an old machine, 2) swamp of despair filling with hope, 3) sweet time after bitterness, 4) disappointed elderly couple in the empty nest, and 5) unappreciation vs. empathetic feelings. These essential themes were comprehensively summarized as "the road leading to the maturation of life with dedication and hope while bearing the weight of caring based on the couple's relationship." Conclusion: The findings indicate that the nature of the caring experience of spouses of elderly individuals with dementia is filled with many dynamic and paradoxical dimensions. Thus, results of the study would help with developing interventions tailored specifically for elderly spouse caregivers to support their role adaptation and ultimately improving their quality of life.

• Korean Parent-Child Health Journal
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• v.18 no.2
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• pp.47-57
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• 2015

Purpose: The purpose of this study is to discover the nature from the life experience of a person with unilateral acquired blindness and his/her family after losing the eyesight and adapting in the environment and to find the meaning of life and how to solve the problem in psychosocial aspect. Methods: This study uses one of the qualitative research methods which explains how families with the unilateral acquired blind perceive blindness after experiencing it and observes how they signify it. starts with interest in lifestyles of individuals and their families and tries to understand the subjective existences of participants in accessible ways and draw the experiences after becoming one-side blind. It cyclically uses deductive verification process through inductive method and establishing hypothesis using materials. Results: According to the results of this study, unilateral acquired blindness studies, due to shattered life, they did not know what to do. Also, discomfort from struggling in a big tunnel and even will to live were found. trying to go out to the world, seeing the new world, and trying to encourage myself, strong attachment to life was shown to by saying, appeared. Each includes sub-topics such as feeling abandoned after confirmed the blindness, feeling disappointed to doctors, family, and friends, trying to live with hope, struggling in a tunnel with thinking how to live, closing the mind from the world, seeing outside the world in the midst of struggling, trying to forget the past with the will of life, having hope to live with care of family, and trying to keep the rest vision. Conclusion: Firstly, in nursing aspect for their adaptation, programs for disable people and nursing intervention focused on their families should be developed. Secondly, since it can be economic and psychological burden for their families and acquaintances, it is necessary to support the blind so that they can find fitted rehabilitation programs and come back to society. Thirdly, active participation of health care providers may influence social interest the improvement of national welfare policy for the unilateral acquired blind.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.525-538
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• 2014

Safety of reactive systems is one of the most important research areas in the field of weapon development. A NoGo response or at least a low-order explosion should be ensured to prevent unexpected accidents when the reactive system is impacted by high-velocity projectile. We investigated the shock-induced detonation of cased reactive systems subject to a normal projectile impact to the cylindrical surface based on two-dimensional hydrodynamic simulations using the I&G chemical rate law. Two types of energetic materials, namely LX-17 and AP-based solid propellant, were considered to compare the dynamic responses of the reactive system when subjected to the threshold impact velocity. It was found that shock-to-detonation transition phenomena occurred in the cased LX-17, whereas no full reaction occurred in the propellant.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.3
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• pp.454-464
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• 1987

The objective of this research is to analyze and evaluate the dynamic flow curve of metals under impact loading at both high strain rate (.epsilon.=1/h dh/dt > 10$\^$3/m/s/m) and large strain (.epsilon.=In h/h$\_$0/ > 1.0). A test method for dynamic compression of metal disc is described. The velocity of the striker face and the force on the anvil are measured during the impact period. From these primitive data the axial stress, strain, and strain rate of the disc are obtained. The Strain rate is determined by the striker velocity divided by the specimen height. This gives a slightly increasing strain rate over most of the deformation period. Strain rates of 100 to 10,000 per second are achieved. Attainable final strains are 150%. A discussion of several problem areas is presented. The friction on the specimen surfaces, the determination of the frictional coefficient, the influence of the specimen geometry (h$\_$0//d$\_$0/ ratio) on the friction effect, the lock-up condition for a given configuration, the friction correction factor, and the evaluation of several lubricants are given. The flow function(stress verus strain) is dependent on the material condition(e.g., prior cold work), specimen geometry, strain rate, and temperature.