• Title/Summary/Keyword: Primary member

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Development of Strength Evaluation System Using the Combined Grillage and Shell Element for the Strength around the Opening (골조구조 해석과 판 요소 해석의 결합을 활용한 개구부 강도평가 시스템 개발)

  • Kim, Sung-Chan;Lee, Kyung-Seok;Song, Jae-Young;Kim, Kyung-Su
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.6
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    • pp.605-611
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    • 2007
  • A ship is composed of many grillage structures especially the deck which is consists of primary girders, transverse and longitudinal members. Several holes are arranged on these primary members for pipes, vents, etc. which cause stress concentration due to the discontinuity of the member. It is not easy to get the stress values around all these holes because of the huge amount of time necessary for computations. In this paper, a simple method to compute for the stress around the holes is suggested. This method is composed of two steps which are grillage analysis for primary members and detailed stress analysis using the results of the grillage analysis. This method is made for the design of the primary members with openings supporting the deck structure.

Long-Term Behaviors of Reinforced Concrete Pier Structures Considering Long Column Effects (철근콘크리트 장주 교각의 시간에 따른 거동)

  • Jung, Hyun-Soo;Kim, Su-Man
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.69-72
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    • 2005
  • For reinforced concrete column under sustained loads, the member suffers additional lateral deflection due to creep. This deflection leads to additional bending in the member, which in turn causes the column to deflect still further. Therefore the secondary moment due to additional deflection causes an increase in primary moment and the strength of column is reduced. And also creep buckling may occur. On this study, nonlinear analysis of reinforced concrete long column including crack effects is carried out and then the strength of long column is revaluated.

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Design for moment redistribution in FRP plated RC beams

  • Oehlers, Deric John;Hasketta, Matthew;Mohamed Ali, M.S.
    • Structural Engineering and Mechanics
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    • v.38 no.6
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    • pp.697-714
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    • 2011
  • Assessing the ductility of reinforced concrete sections and members has been a complex and intractable problem for many years. Given the complexity in estimating ductility, members are often designed specifically for strength whilst ductility is provided implicitly through the use of ductile steel reinforcing bars and by ensuring that concrete crushing provides the ultimate limit state. As such, the empirical hinge length and neutral axis depth approaches have been sufficient to estimate ductility and moment redistribution within the bounds of the test regimes from which they were derived. However, being empirical, these methods do not have a sound structural mechanics background and consequently have severe limitations when brittle materials are used and when concrete crushing may not occur. Structural mechanics based approaches to estimating rotational capacities and rotation requirements for given amounts of moment redistribution have shown that FRP plated reinforced concrete (RC) sections can have significant moment redistribution capacities. In this paper, the concept of moment redistribution in beams is explained and it is shown specifically how an existing RC member can be retrofitted with FRP plates for both strength and ductility requirements. Furthermore, it is also shown how ductility through moment redistribution can be used to maximise the increase in strength of a member. The concept of primary and secondary hinges is also introduced and it is shown how the response of the non-hinge region influences the redistribution capacity of the primary hinges, and that for maximum moment redistribution to occur the non-hinge region needs to remain elastic.

A Study on Problems and Improvements for Membership of Fishing Community (어촌계 가입실태 문제점 및 개선방향)

  • Lee, Chang-Soo;Choi, Wan-Hyun
    • The Journal of Fisheries Business Administration
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    • v.48 no.1
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    • pp.17-29
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    • 2017
  • The primary purpose of this paper is to analyze the membership of fishing community. In order to become a member of fishing community, some conditions are needed both the member of local fisheries cooperatives and resident of fishing village. Generally, many fishing communities have additional conditions such as to be a member of fishing community that is a minimum term of residence, an entrance fee, fishing abilities. These additional conditions play a critical role in making a relationship, building trust and enhancing fairness. However, the setting of excessive additional conditions make it possible to obstruct growth of fishing community.

Fatigue reliability analysis of steel bridge welding member by fracture mechanics method

  • Park, Yeon-Soo;Han, Suk-Yeol;Suh, Byoung-Chul
    • Structural Engineering and Mechanics
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    • v.19 no.3
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    • pp.347-359
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    • 2005
  • This paper attempts to develop the analytical model of estimating the fatigue damage using a linear elastic fracture mechanics method. The stress history on a welding member, when a truck passed over a bridge, was defined as a block loading and the crack closure theory was used. These theories explain the influence of a load on a structure. This study undertook an analysis of the stress range frequency considering both dead load stress and crack opening stress. A probability method applied to stress range frequency distribution and the probability distribution parameters of it was obtained by Maximum likelihood Method and Determinant. Monte Carlo Simulation which generates a probability variants (stress range) output failure block loadings. The probability distribution of failure block loadings was acquired by Maximum likelihood Method and Determinant. This can calculate the fatigue reliability preventing the fatigue failure of a welding member. The failure block loading divided by the average daily truck traffic is a predictive remaining life by a day. Fatigue reliability analysis was carried out for the welding member of the bottom flange of a cross beam and the vertical stiffener of a steel box bridge by the proposed model. Results showed that the primary factor effecting failure time was crack opening stress. It was important to decide the crack opening stress for using the proposed model. Also according to the 50% reliability and 90%, 99.9% failure times were indicated.

Primary Health Care and Desirable Policy Directions in Korea (1차보건의료와 바람직한 정책방향)

  • 박형종;김공현
    • Health Policy and Management
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    • v.1 no.1
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    • pp.95-108
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    • 1991
  • The World Health Organization and its member states, in 1978, declared that primary health care is a key to attain the goal of Health for All by the goal of Health for All by the yeas 2000. As a member state of WHO, the Republic of Korea has participated in the declaration of ALMA-ATA and committed to put national efforts for devedoping and implementing primary health care approach with the spirit and content of this Declaration. Since 1978, to translate the spirit of the Declaration into realization, Korean goverment has developed a new category of health manpower such as Community Health Practitioners serving people living in remote rural areas and Village Health Workers serving voluntarily their own village, strengthened the function of Health Centers and Health Subcenters through their reorientation and improved the infrastructure by their new construction or renovation. While primary health care is viewed as an essential health care in Korea, there are some circles who follow a narrow definition in referring to the health care at the periphey of a health system, which is erroneous. Considering the PHC is accepted as the best alternative approach to health care to solve problems that modern health systems are facing, we propose the followings as desirable health policy directions that modern health systems are facing, we propose the followings as desirable health policy directions which might translate the persopective into action at the national level after reviewing past and current PHC approach in Korea : 1. To improve the equity through the reduction of gaps between those who have access to health care and those who have not. 2. To reinforce multisectoral approach and intersectoral coordination through the re- establishment of the National Health Council or establishment of equivalent organization at the central level. 3. To stengthen community participation through lacal people's empowerment by leadership training, changing planning process from the top-down approach to bottom-up and giving the priority to human resources rater than technology, 4. To reinforce the Ministries of Health and Social Affairs through upgrading its role and function to Coordinate Ministries which involve human welfare policies, and creating a Division which is in charge of PHC in the Ministry.

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GC-MS Analysis of the Extracts from Korean Cabbage (Brassica campestris L. ssp. pekinensis ) and Its Seed

  • Hong, Eunyoung;Kim, Gun-Hee
    • Preventive Nutrition and Food Science
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    • v.18 no.3
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    • pp.218-221
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    • 2013
  • Korean cabbage, a member of the Brassicaceae family which also includes cauliflower, mustard, radish, and turnip plants, is a crucial leafy vegetable crop. Korean cabbage is harvested after completion of the leaf heading process and is often prepared for use in "baechu kimchi", a traditional Korean food. Many of the components in Korean cabbage are essential for proper human nutrition; these components can be divided into two groups: primary metabolites, which include carbohydrates, amino acids, fatty acids, and organic acids, and secondary metabolites such as flavonoids, carotenoids, sterols, phenolic acids, alkaloids, and glucosinolates (GSLs). Using gas chromatography-mass spectrometry, this study examined the variety of volatile compounds (including isothiocyanates) contained in Korean cabbage and its seed, which resulted in the identification of 16 and 12 volatile compounds, respectively. The primary volatile compound found in the cabbage was ethyl linoleolate (~23%), while 4,5-epithiovaleronitrile (~46%) was the primary volatile component in the seed.

Effects of Video-guided Education for Primary Family-caregivers of Stroke Patients (뇌졸중 환자의 주간호제공자를 위한 비디오재활교육의 효과)

  • Cho, Bok-Hee
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.18 no.2
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    • pp.237-246
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    • 2011
  • Purpose: Family-caregivers of stroke patients usually go through hardship and life style changes during the protracted course of a family member's rehabilitation. There is need for programs to educate family-caregivers to better manage the medical crisis. In this study an evaluation was done of the degrees of burden and well-being experienced by primary family-caregivers following video-guided education (VGE) on rehabilitation and family lifestyle changes. Method: Fifty-eight primary family-caregivers of stroke patients on a neurological ward were divided into VGE (29) and control (29) groups. VGE was started within 7 days of patient admission. Interventions included VGE, counseling, and demonstration - re-demonstration. The control group received standard education but not VGE. Data were analyzed using Chi-square test, t-test, ANCOVA, and Pearson correlation coefficients with the SAS program. Results: The VGE group had a significantly lower score for total burden (F=7.19, p=.010) and for sub-scale of time-dependent burden (F=8.44, p=.005) than the control group. There was a negative correlation between primary family-caregiver burden and well-being (r=-.7151, p<.001). Conclusion: Results suggest that the rehabilitation program using VGE was an effective nursing intervention to reduce the burden of primary family-caregivers of stroke patients.

Evaluation to Collision Safety Performance of Stacking Angle Different CFRP/Al Circular Member (적층각이 다른 CFRP/Al 혼성 원형부재의 충돌안전성능 평가)

  • Yang, Yong Jun;Kim, Young Nam;Cha, Cheon Seok;Jung, Jong An;Yang, In Young
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.1-6
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    • 2015
  • The actual condition is that environmental pollution due to the development of various industries has recently become a serious issue. An interest in improving the gas mileage is rising due to an increase in the number of vehicles in the era of high oil price in particular. In order to solve this problem, priority should be given to light-weight design of car body, However, at present, a design method enabling the conventional steel plate to be replaced is direly needed in order to guarantee passengers' safety according to excessive light-weight design of car body. In this study, in order to apply a design method that could realize fuel savings and environmental pollution prevention through an improvement in gas mileage together with meeting the safety requirements for vehicles, it was supposed that CFRP/Al composites member would be used as primary structural member. And to this end, it was intended to obtain optimum design data by experimentally implementing external impulsive load applied to the car body. According to results of impact test of CFRP/Al composites member, a collapsed shape of folding, crack, and bending occurred. So, it was possible to find that energy was observed. And in case of specimen having an angle of $90^{\circ}$ in the outermost layer and stack sequence of $[90^{\circ}{_2}/0^{\circ}2]s$, its collapsed length was shown to be short. Therefore, it was possible to find that the absorbed energy was shown to be higher by 20% or above at the maximum.

Improvement of Energy Efficiency of LEACH Protocol for Wireless Sensor Networks (무선센서 네트워크를 위한 LEACH 프로토콜의 에너지 효율 향상 방안)

  • Lee, Sang-Hoon;Suk, Jung-Bong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.2B
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    • pp.76-81
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    • 2008
  • LEACH (Low Energy Adaptive Clustering Hierarchy) has been proposed as a routing protocol with a hierarchical structure, in order to achieve the energy efficiency that is of primary importance in the wireless sensor networks. A wireless sensor network adopting LEACH is composed of a few clusters, each of which consists of member nodes that sense the data, and head nodes that deliver the collected data from member nodes to a sink node that is connected to a backbone network. A head node in a cluster allocates TDMA slots to its member nodes without taking into account whether they have data to transmit or not, thus resulting in inefficiency of energy usage of head node that remains in active mode during the entire round time. This motivates us to propose a scheme to improve the energy efficiency of LEACH, by assigning TDMA slots only to those member nodes who have data to send. As a result, the head node can remain sleep during the period of no data transmission from member nodes, leading to the substantial energy saving. By using the ns-2 simulator, we evaluate the performance of the proposed scheme in comparison with the original LEACH. Experimental results validate our scheme, showing a better performance than original LEACH in terms of the number of outliving nodes and the quantity of energy consumption as time evolves.