• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.55-55
• /
• 2011

연안 및 해안공학의 발달과 더불어 부유식방파제의 기능적 효율성이 중요시 되고 있다. 흔히 사용되어오던 착저식방파제는 설치에 많은 시간과 경비가 소요되고 환경 및 생태계에 많은 변화를 줄 수 있으며, 설치 예정지의 수리학적 특성 등의 여건에 많은 제약을 받는 단점이 있다. 부유식방파제는 일본 등의 선진국을 중심으로 활용이 잦아지고 있는 방파제로서 수면 위에 설치되기 때문에 수중 생태계에 미치는 영향이 적은 친환경방파제이다. 또한 기존에 시공된 중력식방파제와는 달리 수심에 제한을 덜 받고, 공사기간이 짧기 때문에 경제적이다. 실제 시공사례로는 2007년 마산 원전항에 완공된 부유식방파제가 대표적이며, 지금까지도 부유식방파제에 대한 여러 연구자들의 관심이 증가하고 있는 추세이다. 방파제뿐만 아니라 우리나라처럼 국토의 면적이 작은 지역에서 증가하는 해상물동량을 소화하기 위해서 부유식방파제 등을 이용한 항만의 시공이 필요한 실정이다. 이러한 부유식방파제의 분석적인 측면에 있어서 수치해석은 파랑과 구조물의 상호작용을 해석하는 데 한계가 있으며, 부유식방파제 단면형상을 정확하게 재현할 수 없으므로, 수리모형실험을 통한 부유식방파제의 연구가 필요할 것으로 판단된다. 최근 기술의 발달로 인한 유동장 해명이 가능해 졌으며, PIV(Particle image velocimetry) 및 LDV시스템은 다양한 분야에서 응용되고 있다. 특히, LDV시스템은 측정하려는 한 지점에 대하여 레이저 빔을 단면(Cross-section)으로 만들고 입자의 산란광을 후방산란(Back scatter)으로 받아서 도플러 효과를 이용, 속도에 대한 주파수를 획득하며, 유속을 측정하는 장비로 매우 높은 정확도와 비접촉식 이라는 장점을 가지고 있다. 또한, PIV 시스템에 비하여 측정시간이 오래 걸리는 반면 데이터를 가공하지 않고 활용할 만큼 높은 정확성을 가지고 있다. 본 연구에서는 수리모형실험을 통하여 단독형, 2열형 및 3열형 부유식방파제의 형상, 흘수 및 거리를 변화시키며 유동장을 수집하였으며, 방파성능에 따른 와의 생성 및 소멸시점에서의 파랑변형과의 관계를 분석하였다. 방파제의 형상과 흘수를 달리하여 수리모형실험을 수행하였으며, 와류의 상관관계를 분석하였다. 또한, 연직 2차원 Navier-Stokes 방정식 모형을 이용하여 수치모형실험을 수행하였으며, 수치모형실험 결과와 수리모형실험 결과를 비교 분석하였다. 후방방파제에서 발생되는 파랑은 입사파의 주기가 길어질수록 상대적으로 커지는 현상을 보였으며, 흘수심이 깊어질수록 전방방파제 입사 면에서 자유 수면이 높게 관측되는 결과를 보였다. 또한, 비교적 장주기파랑에 해당하는 입사파랑의 경우 전달파고비 산정에 있어서 설계기준인 0.5를 대다수 초과하는 반면, 3열형 구조에서는 대부분이 0.5이하로 상당히 높은 방파성능 결과를 나타내었다.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.23 no.4
• /
• pp.184-188
• /
• 1987

The author studied to analyse the relationship between the body dimension of sea eel, Astroconger myriaster and the mesh size of fishing gears. The samples were caught by traps and pots during September, 1987 in the Southern Sea of Korea. The results obtained can be summarized as follows: 1. The relationship between total length L, body weight W and diameter D may be expressed as: W=3.58$\times$10 super(-4) L super(3.38) (r=0.99). D=0.07 L-0.59 (r=0.99). W=10.38 D super(2.76) (r=1.00). W=1/2$\times$D super(2).L. 2. The mesh size of traps and the hole diameter of post must be more than 29.2 mm and 18.6 mm, respectively.

• Journal of Korean Home Economics Education Association
• /
• v.28 no.4
• /
• pp.1-20
• /
• 2016

This study aims to investigate the effects of flipped learning applied to home economics education on improving middle school students' academic engagement, self-directed learning ability and social interaction. The subjects of this study were 129 third-grade students in middle school. To verify the effects of flipped learning adequately, 129 middle school students divided into two groups have participated in the study over a course of nine weeks. One group was taught in the traditional instructed learning method while the other one in the flipped learning methods. The two groups were taught in 13 sessions in total once or twice a week, and each session took 45 minutes. For pretest and post test, the questionnaire consisting of academic engagement scale, self-directed learning scale and social interaction scale were used. To analyze data, ANCOVA was used to examine significant differences between two groups. The main results of this study were the following : First, students who participated in flipped learning are more improved than those who participate in instructed learning in academic engagement. Second, students who joined in flipped learning are much more improved than those who joined in instructed learning in self-directed learning ability. Third, students who join in flipped learning were much more improved than those who joined in instructed learning in social interaction.

• Journal of Naturopathy
• /
• v.11 no.2
• /
• pp.93-99
• /
• 2022

Background: It is necessary to understand the correlation between stress and depression according to eating habits in the elderly. Purposes: To empirically verify the mediating effect of eating habits in the relationship between stress and depression in the elderly. Methods: we distributed an 'online questionnaire' to men and women aged 60 or more living in large cities, medium, and small-sized cities in Korea using Google questionnaires, and 365 replies were collected and used for analysis. Results: First, we found that stress in the elderly directly affected depression. In summary, an increment in the stress level of the elderly induces an increment in the depression level. Second, the eating habits of the elderly indirectly mediated the relationship between stress and depression. Conclusions: This study is meaningful in that it has verified eating habits have a mediating effect on the relationship between stress and depression in the elderly, and healthy eating habits of individuals can reduce depression. Therefore, counseling institution must check their daily eating habits when counseling the degree of depression of the elderly. In addition, eating habits are affected by stress, and it is necessary to grasp the individual stress index for the elderly who has terrible eating habits. Furthermore, it is needed to provide continuous nutrition education in institutions and communities to have proper eating habits.

• Journal of the Korean Chemical Society
• /
• v.16 no.1
• /
• pp.46-49
• /
• 1972

Using an assumption of isoviscosity at the gel-point in the polymerization of divinylbenzene, the relations between viscosity equation, viscosity-molecular weight, and the chain transfer equation have been studied. A new equation for the calculation of chain transfer constant, $C_{tr}$, by measuring the gel time in place of the degree of polymerization has been suggested.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.10B
• /
• pp.676-688
• /
• 2005

We introduced mathematical economic analysis model for understanding the fairness of charge from VoIP providers for interconnection of access network. In order to set up this model we made four assumptions predictable in the real world. Also we proposed two accounting method that is flat-rate-pricing and usage-based-pricing and tried to propose which method is more desirable to charge for interconnection on the basis of social welfare and activation of market competitiveness. The outcome of this study includes the reasonable accounting method for interconnection between telephone network and IP Phone network which is most effective to ensure the social welfare and market competitiveness

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6385-6390
• /
• 2015

With bending moment, torsional moment due to geometric properties as "Initial curvature" acts in horizontally curved I-girder. These behavior causes the secondary effect of bending in minor-axis because of interaction between bending and torsion. The bending and torsion interaction cause a loss of load bearing capacity by induced the early inelastic or plasticity condition in curved girder. Also eccentric load by movements of traffic can increase torsion. However, Equation of interaction between bending and torsion for straight girder, not deal with characteristics of curved girder behavior in previous studies, can be overestimated for ultimate strength in horizontally curved I-girder acting vertical force. Therefore, using more rational, obvious suggestion is required when design curved girder. In this study, we identified the bending-torsional moment interaction for the horizontally curved I-girder of the eccentric load acting by FEM analysis.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.30 no.12 s.159
• /
• pp.1759-1767
• /
• 2006

The purpose of this study is to examine the relationship between gender, gift recipient, and group identity by product category of Korean consumers. 672 usable questionnaires from South Korea completed a self- administered survey with a five-point Likert scale. This questionnaire evaluated the perceived importance of group identity when buying apparel and electronics as a gift for kin, nonkin, and co-workers. The interaction between gender, gift recipient, and group identity were statistically significant. The results suggest that the importance of group identity may vary when gender and gift recipient differ by product category. Recommendations for future research are discussed.

• Journal of the Korea Concrete Institute
• /
• v.14 no.6
• /
• pp.1010-1021
• /
• 2002

The current ACI design code does not take into account the contribution of concrete for the torsional moment of reinforced concrete(RC) beams subjected to pure torsion. This code is not capable of evaluating the inter-effects between concrete and torsional reinforcement on the torsional resistance of the RC beams. Some test results indicated that the current ACI code was not successful in predicting the observed torsional moment of the RC beams with reasonable accuracy. The research reported in this paper provides an evaluation equation to predict the torsional moment of the RC beams subjected to pure torsion. The proposed equation is derived from the equilibrium as well as compatibility equations of the truss model for the cracked RC beams. Comparisons between the observed and calculated torsional moments of the 66 tested beams, showed reasonable agreement.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.2
• /
• pp.80-85
• /
• 2005

This study, Using Pusan clay, examined a relationship between Dynamic and Static Liquid Tests. The Static Liquid Tests were carried out based on BS and JIS. The results of the study are summarized as follows. (1) The result of the Dynamic Liquid Limit Test showed that the liquid limit values of Natural condition soil were greater than those of oven-dried soil by $4\%\~15\%$. (2) The liquid limit value of the Static Liquid Limit Test was greater than that of the Dynamic Liquid Limit Test by $2\%\~9\%$. The following equations show the relationship between tile two values. WL, Fall(JIS)=0.961$\cdot$WL, Cas+4.209, WL, Fall(BS)=0.969$\cdot$WL, Cas+5.024, (3) The liquid limit value of BS was greater than that of JIS by $1\%\~6\%$. The following equation shows the relationship between the two values. WL, Fall(BS)=0.976WL, Fall(JIS)+2.638.