• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.5
• /
• pp.331-339
• /
• 2020

In this study, ways to reduce the edge pressure at the bottom plate of the caisson breakwater were considered. The water depth, freeboard, design wave height and period, and the location of the center of gravity on the super-structure of the breakwater were selected as key design variables that influence the edge pressure, and analyzed how the edge pressure changes according to the change of this key variables. The pressure distribution formulae suggested in the design standard was applied for the calculation of design wave forces. Based on the wave forces, the required effective self-weight of the super-structure and the minimum width of the caisson were determined to have a safety factor of 1.2 against sliding and overturning. From the results, it was found that the edge pressure rapidly increased as the water depth increased, and could exceed the allowable bearing capacity when it reached a certain water depth which is 20 m within the analysis conditions. It was also confirmed that the edge pressure gradually increased linearly as the freeboard increased, but decreased with the increase of the wave height and period. This edge pressure could be significantly reduced up to more than 20% by moving the center of gravity of the super-structure to the seaside, which is 5% of the caisson width. Based on the analysis results and the recently conducted research results, a method was proposed to reduce the edge pressure that can be used in the design.

• Journal of Digital Contents Society
• /
• v.12 no.1
• /
• pp.23-32
• /
• 2011

For the past few years, unlike wireless widespread United States and Japan, expensive cost and platform of the mobile web carrier underground and self-centered made achievement of domestic mobile web market sluggish. Nowadays, more and more people pay attention to the mobile web service because of the increased quality of wireless internet, development of mobile device and variety of the flat-rate payment system. However, another big problem is that mobile web is too hard to use. Also, the poor content of mobile web service is an extremely serious problem. In this paper, we put forward a new method for easy to access mobile web service which is use WINC expansion numbers and users can use these numbers to shit their own website. Along with the benefits of purchase WINC number general users are able to make website and control their website at less time and energy.

• Journal of Korea Port Economic Association
• /
• v.35 no.4
• /
• pp.187-206
• /
• 2019

After reviewing the concept and previous studies related to green ports, this study analyzes the implications of green port policy of advanced ports in foreign countries and analyzes problems in terms of environmentally-friendly green port policy for Ulsan port, and to present sustainable green logistics establishment measures. The literature survey and Benchmarking methods are adopted as research methodology and the results are as follows. First, the pan-government climate change response management system, legislation of relevant laws, implementation of fiscal support policies, and roadmaps should be established. Second, the foundation for eco-friendly green growth should be established through the discovery of business models in conjunction with leading industries in the Southeastern Metropolitan Economic Area. Third, the Ulsan Port Greenport, such as AMP, in-port LNG propulsion ship, and ESI vessel incentive, should be built. Fourth, a low-carbon, high-efficiency sea-shuttle service shall be established through the introduction of the sea-shuttle service along the sea route. Fifth, energy self-reliant ports, including all institutions in the metropolitan Ulsan port area that have exceeded the level of Ulsan port Authority, should be built. Finally, water-type ports need to be built through the creation of coastal forests, the purification of marine water quality, and the introduction of colors to port.

• Journal of Digital Contents Society
• /
• v.15 no.6
• /
• pp.663-673
• /
• 2014

The WBAN technology means a short distance wireless network which provides each device interactive communication by connecting devices inside and outside of body. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. Wireless body area network is usually configured in energy efficient using sensor and zigbee device due to the power limitation and the characteristics of human body. Wireless sensor network consist of sensor field and sink node. Sensor field are composed a lot of sensor node and sink node collect sensing data. Wireless sensor network has capacity of the self constitution by protocol where placed in large area without fixed position. In this paper, we proposed the efficient addressing scheme for improving the performance of routing algorithm by using ZigBee in WBAN environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. Therefore proposing x, y and z coordinate axes from divided address space of 16 bit to solve this problems. Each node was reduced not only bitwise but also multi hop using the coordinate axes while routing than Cskip algorithm. I compared the performance between the standard and the proposed mechanism through the numerical analysis. Simulation verified performance about decrease averaging multi hop count that compare proposing algorithm and another. The numerical analysis results show that proposed algorithm reduced the multi hop better than ZigBee distributed address assignment

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.210-210
• /
• 2013

그래핀은 뛰어난 기계적, 화학적, 광학적, 전기적 특성을 가지고 있는 2차원 물질로, 대면적 합성법과 전사 공정을 통해 다양한 기판에서의 사용이 가능해지면서 차세대 전자 소자로 활용하기위한 활발한 연구가 이루어지고 있다. 디스플레이, 태양전지의 전극과 전계 효과 트랜지스터의 채널로 적용한 연구에서 우수한 결과들을 보이고 있다. 특히, 금속/금속 산화물 전극은 염료 감응형 태양전지와 유기 발광 다이오드 구조에서 화학적으로 불안정할 뿐 아니라 일함수가 고정되어 쇼트키 접촉이 형성되면 저항을 낮추기 어렵지만, 그래핀은 금속/금속 산화물 전극보다 화학적으로 안정하고 일함수의 조절이 가능해 옴 접촉 형성에 용이하다. 그래핀의 일함수를 조절하는 연구는 크게 공유결합과 비공유 결합을 이용한 방법이 시도된다. 공유 결합을 이용한 방법은 합성과정에서 그래핀의 구조에 내재된 결함 혹은 새로운 결함을 형성하여 다른 원소를 첨가하는 방법이다. 이러한 방법은 그래핀의 결함 영역에서 작용하기 때문에 그래핀 전자 구조의 높은 수준 조절을 위해선 그래핀 구조의 파괴가 동반된다. 반면, 비공유 결합을 이용한 방법은 전하 이동 도핑 효과를 이용해 그래핀의 전자 구조를 제어하는 방법으로, 금속/금속산화물/기능기와 그래핀의 적층으로 복합 구조를 형성하는 방법이다. 금속/금속 산화물과의 복합구조는 안정적인 p-형 도핑이 보고되었지만, n-형 도핑은 대기중의 수분, 산소 그리고 기판과의 상호작용에 의해 대기중에서 불안정해 추가적인 피막공정이 요구된다. 기능기를 이용한 적층 구조는 그래핀과 기판사이의 상호작용 혹은 그래핀 전자 구조를 다양한 기능기를 이용해 제어하는 것으로, 이극성을 가진 자기정렬 단일층(self-assembled monolayers)이 대표적인 방법이다. 공간기(spacer)의 길이나 말단기(end group)의 종류로 p-형과 n-형의 도핑 수준을 제어할 수 있지만, 흡착기(chemisorbing groups)의 반응성이 기판의 화학적, 물리적 표면상태에 의존하기때문에 기판 선택이 제약되며 전처리 공정이 요구될 수 있는 한계가 있다. 본 연구에서는 다양한 기판에 적용가능한 용액 공정을 이용해 그래핀과 고분자를 적층하였고, 안정적이고 효과적으로 일함수를 낮추는 구조를 확인하였다.

• Journal of Agricultural Extension & Community Development
• /
• v.16 no.2
• /
• pp.363-384
• /
• 2009

This study aimed at finding directions for Korean agriculture to establish a new paradigm of sustainable development. Various problematic issues and concerns in the environment necessitate the transformation of Korea's development paradigm from unconditional growth to "Green Growth" through new policies on green value and review of various advanced researches. In this research, the environment-friendly agriculture's problems, particularly in agribusiness were analyzed. Drawing from Michael Porter's Value Chain Analysis, this research developed a value chain model in agriculture that reflects the environment and the present situations. Future directions in the agriculture sector were also discussed. Korea realized food self-sufficiency through the green revolution in the early 1970s. However, a lot of problems have also occurred, including ground and water pollution and the destruction of ecosystems as a result of the overuse of pesticides and chemical fertilizers. In the late 1970s, the growing interest on environment-friendly agriculture led to the introduction of sustainable methods and techniques. Unfortunately however, these were not innovative enough to foster environment-friendly agriculture. Thereafter, the consumers' distrust on agricultural products has worsened and concerns about health have increased. In view of this, the Ministry of Food, Agriculture, Forestry and Fisheries introduced in December 1993 a system of Quality-Certified Products for organic and pesticide-free agri-foods. Although a fundamental step toward the sustainability of the global environment, this system was not enough to promote environment-friendly agriculture. In 2008, Korea's vision is for "Low Carbon Green Growth" to move forward while also coping with climate change. But primary sectors in a typical value chain do not consider the green value of their operations nor look at production from an environmental perspective. In order to attain sustainable development, there is a need to use less resources and energy than what is presently used in Korean agricultural and value production. The typical value chain should be transformed into a "closed-loop" such that the beginning and the end of the chain are linked together. Such structure allows the flow of materials, products and even wastes among participants in the chain in a sustained cycle. This may result in a zero-waste sustainable production without destroying the ecosystem.

• Journal of Community Nutrition
• /
• v.1 no.2
• /
• pp.108-118
• /
• 1999

This study was designed to examined psychosocial status and nutritional factors(nutrition knowledge, dietary attitudes, eating behavior, dietary intakes) among female university students and to investigate if there were differences in these variables by weight loss attempt. A cross-sectional survey was conducted to 225 female university students in Seoul. Survey instrument was adapted or modified based on literature review, and dietary intakes were assessed using 24-hour recall and CAN-pro. Descriptive statistics, t-test x$^2$-test were used in data analysis. Mean height, weight of subjects were 162.7cm, 51.3kg, and mean BMI was 19.4. One hundred-nine students(48.4%) were grouped into weight loss attempt roup and 116 students were grouped int non-attempt group. According to BMI, 58.7% of weight loss attempt group were underweight, suggesting that unnecessary weight control is common in college women. With respect to psychosocial status, subjects received moderate degree of stress and were slightly satisfied with life. There was no significant difference in stress, social support or self-esteem between the two groups, however, students in non-attempt group were more satisfied with their life(p<0.01) and adapted better in school that students in weight loss attempt group. Subjects scored 14.9${\pm}$2.1 (highest score : 20) on nutritional knowledge, and showed favorable dietary attitudes. Overall, nutritional knowledge and dietary attitudes were not significantly different between the two groups. Common eating problems were irregular meals(71.6%), followed by unbalanced meals and eating-out. Subjects in weight loss attempt group were more likely to change eating habit after entering the university and showed more undesirable eating habit. Dietary intake data indicated hat the energy derived from fat was slightly higher than the recommended level. Most of the nutrient intake was lower than the RDA, particularly, iron and calcium intake was below the 50% of the RDA. Although this study did not reveal significant difference in nutritional knowledge or dietary intake by weight loss attempt, this study showed status of weight control, eating habit and dietary intake in female university students, and provide some information for nutrition education of college women.

• Journal of IKEEE
• /
• v.20 no.3
• /
• pp.220-225
• /
• 2016

In this paer, low on-resistance and high-power trench gate MOSFET (Metal-Oxide-Silicon Field Effect Transistor) incorporating current sensing FET (Field Effect Transistor) is proposed and evaluated. The trench gate power MOSFET was fabricated with $0.6{\mu}m$ trench width and $3.0{\mu}m$ cell pitch. Compared with the main switching MOSFET, the on-chip current sensing FET has the same device structure and geometry. In order to improve cell density and device reliability, self-aligned trench etching and hydrogen annealing techniques were performed. Moreover, maintaining low threshold voltage and simultaneously improving gate oxide relialility, the stacked gate oxide structure combining thermal and CVD (chemical vapor deposition) oxides was adopted. The on-resistance and breakdown voltage of the high density trench gate device were evaluated $24m{\Omega}$ and 100 V, respectively. The measured current sensing ratio and it's variation depending on the gate voltage were approximately 70:1 and less than 5.6 %.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.39 no.1
• /
• pp.55-63
• /
• 2013

Applications of nano-emulsion for cosmetics as a means of promoting dermal absorption have been the subject of interest. In this study, the stability of nano-emulsions prepared by low-energy emulsification method and varying the composition of raw materials was investigated. By measuring the particle size of the nano-emulsion against time, the stability of nano-emulsions prepared by adding polyol to water phase was increased significantly compared with the nano-emulsions prepared by adding polyol to ethanol phase. The speed of adding ethanol phase to water phase did not have a significant impact on the particle size and stability. Depending on the type of oil, stability was not affected. However, there would be a correlation between the initial size of the nano-emulsion droplets and the molecular weight and polarity of the oil. Stability and the initial particle size according to the type of polyols showed a similar trend except 1,2 hexanediol. The initial droplet size was affected by the concentration of surfactant and oil. However, the initial droplet size did not change against time. Concentration of ethanol was observed to have a significant impact on the initial particle size and stability.

• Korean Journal of Community Nutrition
• /
• v.19 no.2
• /
• pp.142-162
• /
• 2014

Objectives: To evaluate the critical environmental factors on healthy-aging of Korean people, we investigated the significant factors influencing health status of septuagenarians living in rural area of Jeonla province, known to be one of the representative longevity regions in Korea. Methods: We divided subjects into healthy group (36M/25F) or poor-health group (26M/73F) based on self-reported health status, body mass index, a number of prescription, and blood test data. General characteristics, physical measurements, lifestyle, dietary behavior and nutrient intake, physical health and mental health data were statistically compared between the two groups. Results: Average age was not different between healthy group and poor-health group in men and women, respectively. In men, significantly favorable factors to health were observed to be higher education, regular exercise, higher grip strength and walking function, body mass index (${\geq}18.5kg/m^2$), moderate frequency of drinking and eating-out, non-smoking, normal red blood cell (RBC) count, higher serum dehydroepiandrosterone-sulfate (DHEAS) level, good digestive function and appetite, normal hearing function, regular meals, adequate vegetable and fruit intake, diverse food intake, adequate energy and nutrients (protein, vitamin $B_1$, $B_6$, C and E, folate, niacin, P, Zn and K) intake, higher mini-nutrient status assessment (MNA) score and low level of depression. On the other hand, in women, those were literacy, living arrangement, moderate frequency of drinking, healthy teeth, higher grip strength and walking function, bone mineral density, normal RBC and white blood cell (WBC) count, higher DHEAS concentration, higher MNA score, normal cognition and memory function, having snack and adequate fruit intake. Conclusions: These results could be useful to plan effective strategies to increase health-life expectancy of Korean old people living in rural areas.