• 대한조선학회논문집
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• 제59권2호
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• pp.96-108
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• 2022

In this paper, we propose a systematic hull form variation technique which automatically satisfies the displacement constraint and guarantees a high level of fairness. This method is possible through multiple parameter correction curves. The present method is to improve the hull form variation method based on parametric modification function and consists of two sub-categories: SAC variation and section lines modification. For SAC variation, the utilization of two B-Spline curves satisfying GC¹ condition led to the satisfaction of displacement constraint and high level of fairness at the same time. Section lines modification methods involves in using two fuctions: the first is the waterplane modification function combining two cubic splines. the other function is the sectional area modification function consisting of 2nd order polynomial over the DLWL(Design Load Waterline) and 3rd order polynomial below the DLWL, This function enables not only the fundamental U-V section shape variation but also systematically modified section lines. The present method is expected to be more useful in the hull form optimization process using CFD compared to the existing method.

• 수완나부미
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• 제6권2호
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• pp.3-18
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• 2014

With natural resources-terrestrial or coastal-fastly diminishing, governments are now resorting to biodiversity conservation, fast-tracking the introduction of new legislations, as well as the amendment of existing ones, and laying out programs that interpret existing practices and research agendas. This paper examines how biodiversity conservation-in addition to eco-tourism-has become an important symbol of the modernizing state of Sabah, Malaysia. It further examines the effects of biodiversity conservation on state and community management of natural resources, with particular reference to the management of natural resources by the indigenous peoples of Sabah. Citing case studies and focusing on a forest community at Kiau Nuluh, in the district of Kota Belud, Sabah, this paper evaluates strategies used by indigenous groups to maintain access and control over the management of natural resources-and by implication to livelihoods-via ecotourism, making creative alliances with non-government organisations as well as forging cooperation with government agencies which act as custodians of these resources. For a majority of indigenous groups however, the practice of biodiversity conservation has meant reduced and controlled access to natural resources, considering the fundamental issue of the lack of security of tenure to the land claimed under customary rights. New initiatives at recognizing Indigenous and Community Conserved Areas (ICCAs) by international conservation groups provide a means for tenure recognition, for a price, of course. The recognition of ICCAs also faces obstacles arising from developmentalist ideology which upholds that forests are valuable only when converted to other land use, and not left to stand for their intrinsic value.

• Fibers and Polymers
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• 제7권4호
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• pp.424-431
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• 2006

Roll drafting, a mechanical operation attenuating fiber bundles to an appropriate thickness, is an important operation unit for manufacturing staple yams. It influences not only the linear density regularity of the slivers or staple yams that are produced, but also the quality of the textile product and the efficiency of the thereafter processes. In this research, the dynamic states of the fiber bundle in the roll drafting zone were analyzed by simulation, based on the mathematical model that describes the dynamic behavior of the flowing bundle. The state variables are the linear density and velocity of the fiber bundles and we simulated the dynamics states of the bundle flow, e.g., the profiles of the linear density and velocity in the draft zone for various values of the model parameters and boundary conditions, including the initial conditions to obtain their influence on the dynamic state. Results showed that the mean velocity profile of the fiber bundle was strongly influenced by draft ratio and process speed, while the input sliver linear density has hardly affected the process dynamics. Velocity variance of individual fibers that could be supposed to be a disturbing factor in drafting was also influenced by the process speed. But the major disturbance occurred due to the velocity slope discontinuity at the front roll, which was strongly influenced by the process speed. Thickness of input sliver didn't play any important role in the process dynamics.

• 한국표면공학회지
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• 제41권5호
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• pp.194-198
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• 2008

Several methods for improving dispersion of carbon nanotubes (CNTs) have been investigated. CNTs modified by acids and hydrogen peroxide ($H_2O_2$) showed improved dispersion. From SEM micrographs and photos of dispersion, CNTs modified with nitric acid and $H_2O_2$, showed no agglomeration in solution even standing for 4 months, which means successfully improved dispersion property. TEM micrographs of surface modified single CNT treated with 69% $HNO_3$ in boiling acid solution as the optimum method were obtained. For confirmation of CNTs' application to EDLC electrode materials, characteristics of EDLC have been analyzed by cyclic voltammetry curve, specific capacitance of unit cell, electrode discharge curves and AC impedance curve. From the results, it could be confirmed that electrochemical properties of CNTs were enhanced after surface modification with 69% $HNO_3$ acid treatment.

• 교육녹색환경연구
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• 제9권1호
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• pp.41-51
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• 2010

It is high level of management activity for the fixed property of building to operating spaces for education in university campus. Therefore, this study is focused on definition of the factors for analyzing the actual conditions of space operation and application of them to C university campus in Gyeongbuk in the aspect of infrastructure of university and efficiency of space operation. These analytical factors are the rate of lecture and experimentation room, the rate of theoretical and experimental subject in curriculum and unit area for infrastructure and the rate of use, turnover rate and occupation rate per lecture for space operation. If the analytical factors of space operation are systemized as program module for space operation, the space management system of university campus will be characterized on the foundation of university information system. And it will be able to support the decision making about space management. It needs to integrate various type of information and data of university to increase the efficiency of decision making.

• 한국멀티미디어학회논문지
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• 제23권10호
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• pp.1307-1317
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• 2020

In recent years, the PV plant is gradually increasing in korea and has begun to focus on PV system O&M(Operation and Management). The legacy PV system can hardly be gathering realtime information. That is why it is difficult for the facility to respond immediately to situations in which problems arise. This leads to economic losses due to reduced power generation. In this study, we implemented an RMC(Remote Maintenance Control) gateway that supports multi-area equipment(inverters, junction boxes, switchboards, environmental sensors) that are not limited to specific manufacturers. It provides a function to visualize the collected data. Users can easily check the power generation and operation status of PV system equipment. In the future, we will develop an algorithm capable of analyzing beta factors that cause equipment performance degradation, parts aging, and deterioration using data collected from facilities. We intend to use this algorithm as a fundamental technology for O&M by transplanting it to the RMC gateway.

• 자원ㆍ환경경제연구
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• 제24권2호
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• pp.251-281
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• 2015

This paper examines the perceptions of sustainability, which is conceptualised as cross-generational social preferences, on the formation of international environmental agreements (IEAs) in a two-stage game in two periods. There are two scenarios are considered: myopic and sustainable development scenarios. The myopic scenario assumes the decision makers only concern the present welfare. Whilst the scenario of sustainable development has two characters: cross-generational fairness and altruism. When both are taken into account, a coalition will be expanded. The numerical example indicates that the marginal cost of the total emissions is the crucial factor for the formation of IEAs. Only when the marginal cost is low, a sustainable system can be succeeded. While, the technological advancement may lead to a more efficient production per unit of emissions, it also encourages countries to emit more in total and have a lower level of welfare. The results confirm the importance of sustainability to IEAs. The lesson learnt from this study is: when decision makers are myopic, the system is unsustainable even if an IEA is formed. Only when the perception of sustainability is considered, the system could be sustainable. Regardless of the existence of IEAs, international environmental conventions shall not neglect the fundamental goal to pursue sustainable development.

• KIEAE Journal
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• 제11권4호
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• pp.95-101
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• 2011

Earth has been used as a building material not only our country but also many foreign countries in the world. In foreign countries, we can often find the high-storied earthen houses which have been maintained for over several hundred years, which means the fact that earth differs in durability according to the methods of utilizing earth. So, the purpose of this study is to progress the fundamental research for utilizing earth as a wall material. Also, the another purpose of this study is to utilize the optimum micro-filler effect which adjusts the grain size of earth and the lime composite which promotes chemical combining power, and so examine whether earth material ensures its high compressive strength. This study applied both of rammed earth method and pour earth method among earth architecture methods. This study investigated compressive strength, slump, and air content according to unit binder weight. On the basis of such experimental results, this study derived the following conclusions. 1) Optimum micro-filler mixtures reduce a lot of fine particles contained in earth. If optimum micro-filler mixtures are used as aggregates, they develop lower W/B and relatively higher strength than general earth. 2) In this study, which uses optimum micro-filler earth mixtures and lime composite, rammed earth method develops 29MPa and pour earth method develops 28MPa in 28 days compressive strength. Such strengths can be utilized in building walls.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.232-238
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• 2009

The objective of this study is to investigate the suitable design for a domestic CWP pump, which is used in cooling-water intakes for the unit 3 and 4 of Yeonggwang nuclear power plant. All the simulations are performed, using CFD method with a commercial code STAR-CCM+ version 3.02. After modeling a present design of the pump, the flow around the rotating blade was calculated by using quasi-static method and sliding mesh method with the almost same condition as an actual state. Based on fundamental simulations with various depth of sea water, the reference pressure for the boundary condition of the present study was decided. To verify the reliability of the calculation results, the suction flow rate of the data was compared with that of the experimental data. As a result of this comparison, it is confirmed that two results are fairly consistent. For the improvement of the suction flow rate, computational analysis was done by changing a flow channel and blade shapes. It is shown that the suction flow rate of the new pump was improved.

• 대한가정학회지
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• 제32권3호
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• pp.217-226
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• 1994

Cloth culture is one of the basic unit of constructing man's culture in a life of human being. One of the fundamental elements to construct cloth culture is the silk-fabric from the ancient time-Sam Han period B.C 2∼4 Korea. This study is to survey the growing aspects of the silk-fabric influence Goguryo & Bakje dynasty. It is an attempt to manifest that how silk-fabric influence through a trade or as means of currency between the two nations at that time. through a trade or as means of currency between the two nations at that time. To certify I use material such as San guo zhi, Hou Han han shu from China Samkuksaki Dong-kuk-tong-gam from Korea and NiHon Shoki from Japen and I concerned the cultural relations of politics economics and socity of the two dynastics so as to prove a relations of politics economics and socity of the two dynastics so as to prove a relative relation between the two. It is reached to the conclusion that silk fabric had been a constituent role at cloth culture at that time of Goguryo & Bakje. It is pointed out that silk-fabric had been an important role to construct the culture of social economic and politic through a trade and as a precious currency.