• Journal of Korea Water Resources Association
• /
• v.37 no.11
• /
• pp.889-896
• /
• 2004

The fractal advection-diffusion equation (ADE) is a generalization of the classical AdE in which the second-order derivative is replaced with a fractal order derivative. While the fractal ADE have been analyzed with a stochastic process In the Fourier and Laplace space so far, in this study a fractal ADE for describing solute transport in rivers is derived with a finite difference scheme in the real space. This derivation with a finite difference scheme gives the hint how the fractal derivative order and fractal diffusion coefficient can be estimated physically In contrast to the classical ADE, the fractal ADE is expected to be able to provide solutions that resemble the highly skewed and heavy-tailed time-concentration distribution curves of contaminant plumes observed in rivers.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.93-93
• /
• 2015

최근 들어 전 세계적으로 극심한 기후변화와 그에 따른 기상이변으로 국지성 집중호우로 인한 홍수피해가 급증하고 있으며, 그의 피해규모 또한 대형화되고 있는 추세이다. 국내의 경우 1990년 중반부터 매년 국지성 집중호우나 이상호우로 인한 피해가 반복되고 있고, 그밖에 경우 7월과 8월 여름철에 강우가 집중되며 일정한 강우패턴이 사라지고 있다. 이러한 기상재해에 따른 피해를 줄이기 위해 강우-유출 현상에 관한 정교한 해석이 필요하며, 단기간에 발생되는 호우사상에 대한 유출해석은 홍수관리 측면에서 중요한 역할을 한다. 본 연구에서는 국지성 집중호우 및 돌발홍수가 잦은 낙동강수계인 경상남도 양산에 위치한 양산천을 대상유역으로 선정하여 홍수유출모의를 실시하였으며, 홍수유출모의에는 분포형모형인 S-RAT모형과 VfloTM모형을 사용하여 모의하였다. S-RAT모형의 검증을 위해 동일한 사상을 이용하여 보정 및 검증을 하였다. 또한 VfloTM 의 Inundation Tool을 이용하여 홍수범람모의를 하였고, 통계학적 분석을 통하여 두 모형의 오차를 계산하여 S-RAT모형의 국내 유역 적용성을 검토하였다.

• Journal of Korean Public Health Nursing
• /
• v.33 no.1
• /
• pp.109-122
• /
• 2019

Purpose: The purpose of this study was to understand the meaning of the driving force of life experienced by the elderly and the realistic structure of their experience. Methods: The research question was "What is the essential meaning of the driving force experienced by the elderly?". Data were collected from individual in-depth interviews between March, 2017 and May, 2017 and analyzed using Van Manen's hermeneutic phenomenological methodology to identify the essential themes of their experience. Results: Through the analysis process, 22 themes and 14 essential themes were derived. The 14 essential themes of the driving force of the life of elderly were as follows: 'Memories from the past', 'Poverty to escape', 'Hand down family's heritage', 'A body bound by marriage', 'A body necessary for old age', 'A dignified body even if they grow older', 'A body that does not want to fall', 'A fruit of my life', 'Mature real love', 'Unchanging fraternity', 'Extended family', 'An old friend with whom share my heart', 'Satisfied with the situation', and 'Expanding the breadth of life'. Conclusion: Nursing programs that assess the driving force of life supporting the elderly and supports the driving force of such a life should be developed.

• Women's Health Nursing
• /
• v.30 no.2
• /
• pp.140-152
• /
• 2024

Purpose: Social support is essential for postpartum well-being, but little is known about the postpnatal social support preferred by primiparous women. This study aimed to comprehensively understand and describe the meaning of postnatal social support experience in primiparous women. Methods: The participants were seven primiparous women who were within 1 year after childbirth, recruited through purposive and snowball sampling from an online parenting community. The data were collected through in-depth interviews from November 14 to 28, 2022. Participants were interviewed face-to-face or via phone or online platform, according to their choice. Colaizzi's phenomenological qualitative research method was applied to analyze the meaning of the participants' experience. Results: Five theme clusters and fourteen themes were identified from the data. The five theme clusters are as follows: (1) Shortcomings of the childbirth and postpartum care system I learned through my experience; (2) Government policies focusing on childbirth and child-rearing rather than postpartum recovery; (3) Driving force of postpartum recovery: Shared childbirth process; (4) Childcare on my own; and (5) Conflicted between being a stay-at-home mom and a working mom under inadequate maternity protection policies. Conclusion: Despite postpartum support from the government that was perceived as inadequate, first-time mothers regained confidence and motivation for parenting with the help of family, peers, and social networks. First-time mothers need support from professionals and reliable online communities for postpartum recovery and parenting.

• Journal of the Daesoon Academy of Sciences
• /
• v.36
• /
• pp.117-152
• /
• 2020

In Daesoon Thought, Matteo Ricci is regarded highly as a Jongjang, 'religious leader,' (of Christianity). This paper deals with the life and philosophical/theological thought of Matteo Ricci as homo-religiosus from the perspective of phenomenology of religion. Examining his historical background and biographical sketch, I will analyze Ricci's understanding of God, humanity, and salvation and re-evaluate his relationship with Daesoon Thought. Matteo Ricci, born in Italy, became a Jesuit missionary to China and transmitted various products of western civilization. Accepting the pro-cultural approach of Jesuit mission, he applied it to Chinese culture and language by learning the Chinese language and regarding Chinese people as his friends. This was a sympathetic way to transmit Western religion and culture while on Chinese soil. He suggested eight reasons to look towards the future of China with optimism and taught Chinese people his Christian message through his indirect means of understanding and persuasion. In China, Jesuit missionaries called the Christian God 'Tianzhu (Cheonju in Sino-Korean),' meaning Lord of Heaven. Ricci identified the Confucian notion of 'Shangdi (Sangje in Sino-Korean),' meaning Supreme Emperor (or God) with Tianzhu. While translating Confucian scriptures, he found the common ground between Confucianism and Christianity to be the monotheism of ancient Confucianism. He criticized the concepts of God in Buddhism and Daoism, and justified the Christian doctrine of God by way of a Confucian understanding of deity. Ricci's understanding of humanity was based on his Christian faith in creation, and he criticized the Buddhist concept of transmigration. He proposed Christian ethics and doctrine of salvation by using discourse on the afterlife and in particular, the concepts of heaven and hell. Concerning the relationship between Daesoon Thought and Ricci, the following aspects should be examined: 1.) Ricci's contribution to the cultural exchanges between East and West, 2.) his peaceful approach to his mission based on dialogue and persuasion, 3.) the various activities conducted by Ricci as a Christian leader, and 4.) his belief in miraculous healings. His influence on Korea will likewise be explored. Ricci's ultimate aim was to communicate with Asian people and unify East and West under a singular worldview by emphasizing the similarities between the Christian and Confucian concepts of God.

• Journal of the Korean Magnetics Society
• /
• v.14 no.1
• /
• pp.33-37
• /
• 2004

Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ has been studied with Mossbauer spectroscopy, x-ray diffraction, vibrating sample magnetometer (VSM), and magnetoresistance (MR) measurement. The crystal structure was determined to be a cubic spinel with lattice parameter a$_{0}$=9.9880 $\AA$. The MR measurements show a semiconductor behavior below 110 K and metal behaved above 100 K. The temperature dependence of magnetization of Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ was reported. In addition to a large irreversibility between the zero-field-cooling (ZFC) and the field-cooling (FC) magnetization at applied field H=100 Oe, a cusp-like anomaly was observed in both the FC and ZFC curves. It shifted toward the lower temperature region with increasing magnetic field, and then showed convex type maximum at 110 K, under the applied field of 5 kOe. The Mossbauer spectra were measured from 15 K to room temperature. The asymmetric line broadening was observed for the sample Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$, and it was considered to be dynamic Jahn-Teller relaxation. The charge state of Fe ions was ferrous in character. The unusual reduction of magnetic hyperfine field below 110 K was interpreted in terms of cancellation effect between the mutually opposite orbital current field (H$_{L}$) and Fermi contact field (H$_{C}$).

• Journal of Korean Academy of Nursing
• /
• v.30 no.2
• /
• pp.452-462
• /
• 2000

There are currently 214 orphanages in Korea which house approximately 13,873 orphans aged between 3 and 18; this accounts for about 0.12% of all children in the same age range. Some have lost their parents, but most have come after their parents divorced or broke up. This means majority of the children in Child Care Centers have parents. Traditional virtue of obedience to parents (Hyo) was regarded as one of the highest value in Korea. Also the interaction between parents and their children was regarded as basic human nature that parents look after, both physically and spiritually, their children until they become one of the matured social member. Raised without having a chance to realize their filial duty and not having been cared for by their parents, most orphans feel that they lack something in their lives when compared with friends. In the end, they live their lives longing for their parents and go through mental discord about their parents. This paper is focused on understanding orphans' experience and views on parents. I approached the issue by applying van Manen's Hermeneutic Phenomenological Approach. The interviews, along with other reference material were phenomenologically reflected to draw essential themes as follows; 1. Orphans of pre-school age hazily long for parents without having any practical image of their parents. 2. They occasionally dream meeting their parents with image that can only last in their dreams, and this continues up through middle school. 3. At the age of elementary school, they crave the image of parents as they see their friends with their parents. 4. They start to despise their parents for having abandoned them when they reach puberty. 5. Meanwhile, as their vague image of parents fade away, they attempt to give up their thoughts toward their parents. 6. Highteens start to think in terms of fate. 7. They don't long for their parents anymore as they used to, but still wishes to meet them at least once. However, they don't want to start any kind of a relationship with them. 8. They fear that they will also fail in raising families of their own, and making their children orphans too, just like their parents have. They simply don't want to follow their footsteps. 9. Thinking that they were abandoned by their parents, they are reluctant to believe other people.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.770-774
• /
• 2009

한강하구 일대는 세계최대 규모의 갯벌이 조성되어 해양생태계에서 중요한 역할을 수행하는 곳이다. 육상기원의 퇴적물이 흐름이 완만한 하구 주변부에 퇴적되어 대규모의 갯벌을 생성하여 육상에서 유입되는 많은 유기물이 집중되고 탁도가 높아 대량의 플랑크톤과 같은 일차생산자가 상대적으로 부족한 대신에 담수 유입이 많아 하구와의 거리에 따른 일정한 염분 구배를 가지고 있어 더욱 다양한 환경이 조성되어 있음에도 1980년대 후반부터 각종 매립사업과 한강종합개발사업($1982{\sim}1986$)이 실시되어 한강하구의 습지가 줄어들고, 해안침식, 토사유입, 퇴적, 적조현상, 갯벌 및 해수오염과 같은 결과를 가져왔다. 1990년대에는 한강하구지역에서 퇴적으로 인한 홍수 예방과 건설골재 확보를 위한 준설이 활발히 이루어졌으나, 이로 인한 습지생물 서식처 파괴와 같은 환경영향이 우려되어 현재는 실시하지 않고 있다. 무차별적인 개발계획으로 매년 홍수 때마다 피해를 입는 김포일대, 한강과 임진강 지역의 수위 및 흐름 영향을 살펴보고 향후 대책 수립을 검토해야 한다. 이에 본 연구에서는 한강하구의 유사이송에 의한 수리학적 특성을 분석하기 위해 상류로부터 이송되어온 유사에 대하여 시간적 흐름특성을 통하여 조성된 한강하구의 특징을 분석하였고, 지형변화 분석을 위해 MIKE 21 프로그램의 이동상 해석모듈을 사용하여 지형변화에 따른 한강하구에서의 홍수기 하상변화와 유수 흐름 및 수위등의 변화를 모의하였다. 그 결과 예성강과 한강의 유수흐름은 청주초를 통하여 외해로 유출되고 이 흐름은 대부분 강화도와 교동도 사이의 교동수로로 유출되는 것으로 나타났으며, 염하수로 합류부 및 임진강 합류부에서는 침식 및 퇴적이 활발히 일어나는 것으로 모의되었다. 향후 수리학적 특성변화에 따른 유사의 퇴적 및 세굴에 의한 한강하구 지역의 지형변화를 분석하여, 주변 환경영향에 대한 대책 수립을 검토해야 할 것이다.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.05a
• /
• pp.59-64
• /
• 2005

Although experimental analysis for groundwater sample at wells located systematically are very effective to delineate seawater intrusion region at coastal area, this method is restricted in few wells and time. We have conducted electrical resistivity sounding at 30 points in the study areas to analyze the region of seawater intrusion and found the boundary between salt wedge and fresh water lens from the analysis results of geostatistical method using variogram for one-dimensional inversion results. The methodology adopted in this study would be useful for finding the seawater intrusion region and evaluating quantitatively.

• Journal of the KSME
• /
• v.16 no.4
• /
• pp.41-48
• /
• 1976

재료의 피로문제에 대해서는 꽤 오래 전부터 많은 연구가 이루어져왔고, 피로의 현상파악에서부 터 피로이론의 구명, 나아가서는 실제문제로서의 피로설계, 피로수명예측 등에 기여한 업적은 아 주 크다 하겠다. 그러나 종래의 피로문제연구의 방향이, S-N 곡선에서 얻어지는 피로한계강도 (더 정확한 표현으론 피로파괴한계강동)에 바탕을 두고, 정력확적인 설계관례인 안전계수의 도입 을 빌려, 피로강도를 실용화할려는 선에서 이루어져 왔다고 보겠다. 재료의 피로한계강도란, 그 정의로 미루어, 다분히 정적으로는 극한강도 또는 피로강도의 개념에 견주어 질 수 있는 공칭응 력으로써 탄성학적으로 해석될 수도 없고, 다만 탄역성이론의 개념을 바탕으로 근사해석례만이 허용되고 있을 뿐이다. 재료에는 소위 평활재이건 절결재이건 간에 또 검출여부에 관계없이, 내외 부에 대소각종의 결함이나 역학적 불연속부가 잠재해있음은 이미 공지의 사실이며, 이들 결합, 불 연속부등이 외하중하에서 응분의 응력집중원이 되어 재료를 전반적인 파괴로 몰고 갈 수 있다 함 도, 또한 이러한 역학적거동이 피로파괴에 까지 확장해석될 수 있을 것이란 것도 이미 잘 알려져 있는 터이라 하겠다. 재료내외부의 제결합을 응력집중이 극대인 crack로 대체해서 외하중하에서 의 응력장거동을 해석한 선형탄성파괴역학(LEFM)은, 바로 이러한 실제재료의 강도설계에 보다 큰 정확성을 부여한 방법론적 학문이라 하겠고, 나아가서는 재료의 파괴기구를 파헤치는데 진일 보적인 역학적인 수법이라 하겠다. 취성파괴, 연성파괴에 바탕을 둔 파괴역학(LEFM)을 피로파괴 에 적용시키는 데는 상당한 문제점들을 수반할 것임은 충분히 인지되나, 제한된 경계조건하에서 의 적용 예는 종래의 어떤 방법에 의한 것 보다도 피로강도설계, 안전사용 피로수명예측 등에 획기적인 진전을 보여주고 있다. 파괴역학은 crack 재의 강도학이고, 더 구체적으로 음력학대계수 (stress intensity factor) K 또는 이와 연연되는 parameter 인 strain energy release rate(G), crack-tip plactic zone size r$_{p}$,.rho., crack-tip opening displacement .phi., strain intensity 등을 쓰는 재료강도학이기 때문에, 이 수법을 피로파괴에 적용시킴은, 종래의 공칭응력으로 피로 문제를 다루던 방법과는 판이하다 하겠다. 본고에선 파괴역학의 관점에서 피로구열의 안정성장을 논하고, 과거 10여년간의 피로 crack문제에 대한 연구방법, 실험방법 등을 소개하는 방향으로 고 를 진행시켜 나가겠다.