• 공학교육연구
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• 제18권4호
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• pp.45-56
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• 2015

The goal of this study was to analyze the research trends of engineering education in elementary and secondary education. To accomplish this goal, this study analyzed the journal papers by 'published year', 'research topic', 'research subject', 'research method' and 'related school subject'. Followings are the results of this study. First, regarding the published year, the studies related to the elementary and secondary school level engineering education had been conducted 1 to 3 pieces intermittently from 1995 to 2009. And the number of studies are more than 5 pieces after 2010. Second, regarding the research topic, the number of study followed by 'investigation for current status', 'tendency analysis', 'development of teaching method or model', 'verification of teaching method/models' effect'. Third, regarding the research subject, the number of study followed by 'student', 'literature', 'professor', 'teacher'. Fourth, regarding the research method, the number of study followed by 'survey research' and 'literature research', 'qualitative research', 'experimental research' and 'integrated research'. Fifth, regarding the related subject, the number of study followed by 'science', 'technology', 'mathematics', 'practical arts'. Based on the results of this study, there are the needs for further studies to establish theoretical foundation on the engineering content elements in elementary and secondary school level, analyze on related variables and effects, develop engineering assessment instrument, use a variety of research methods, and conduct study on the applications of engineering in math subject.

• 산업공학
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• 제18권4호
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• pp.402-411
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• 2005

Secondary batteries with high performance are essential in widespread use of modern portable devices such as cellular phones and laptop computers. High energy density, long cycle life, and safety are some of important requirements for secondary battery. To achieve such characteristics, a mixing proportion of electrolyte solution ingredients in the battery should be carefully chosen. In this paper, using statistical design of mixture experiments (DOME), we attempt to find an optimum condition of designing the secondary battery. DOME has a distinct feature in that the experimental region is represented by simplex, rather than hypercube, because the sum of blend proportions should be unity. Several designs based upon this point have been proposed for mixture experiments. Among them, an extreme vertices design is employed in this paper because there are a couple of blend constraints to be considered. In order to investigate how the mixing proportion interacts with other manufacturing factors, a fractional factorial design is also included across the extreme vertices design. As a result, we find that the blend proportion of solution ingredients has a significant effect on battery performances. By simultaneously optimizing two battery capacities, this paper proposes an optimum blend proportion according to process factor settings.

• 대한기계학회논문집B
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• 제20권9호
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• pp.2924-2932
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• 1996

As the environmental pollution can be greatly reduced and the waste heat can be also recovered through a combustion of municipal solid waste, the incineration begins to be highlighted recently in our country. But it is very difficult to be operated with constant combustion conditions for a long time as the domestic waste is composed of various components, contains a large percentage of water, and has a low heating value. Therefore, the cold flow test and partial hot flow test were conducted in the incinerator by use of injection angles of a secondary air affecting fluid flow as the first action to maintain the optimum combustion conditions. A model to a scale of 1:10 was designed and manufactured through the similarity of model and prototype flows. Velocities and temperatures were measured through the experiment. From the results, fluid flows of secondary air obtained from partial hot flow test correspond almost well with those of main flow obtained from cold flow test. Consequently, injection angles of secondary air are proved to affect main flow decisively.

• 대한간호학회지
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• 제41권1호
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• pp.47-60
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• 2011

Purpose: This study was conducted to develop an e-Learning program that assists nursing students' clinical Purpose: This study was conducted to develop and evaluate a web-based education program for secondary stroke prevention. Methods: A web-based secondary stroke prevention education program was developed using the system's life cycle methods and evaluated by comparing the effects of education among three groups, a web group, a booklet group and a control group. Results: Knowledge level of both patients and family, as well as some health behavior compliance in the web-based and booklet education groups were significantly higher than those of the control group. Family support in the web-based and booklet education groups was significantly higher than that of the control group after 12 weeks. The urine cotinine level in the web-based education group was significantly lower than that of the control group after 12 weeks. Medication adherence, blood pressure and perceived health status were not statistically different among the three groups at any time. Conclusion: Webbased and booklet education programs were equally effective regarding the level of knowledge of patients and their families, family support, health behavior compliance, and urine cotinine level. These results demonstrate the potential use of a webbased education program for secondary stroke prevention.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4623-4643
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• 2015

This paper considers physical-layer security protocols in multicast cognitive radio (CR) networks. In particular, we propose dual-hop cooperative decode-and-forward (DF) and randomize-and-forward (RF) schemes using partial relay selection method to enhance secrecy performance for secondary networks. In the DF protocol, the secondary relay would use same codebook with the secondary source to forward the source's signals to the secondary destination. Hence, the secondary eavesdropper can employ either maximal-ratio combining (MRC) or selection combining (SC) to combine signals received from the source and the selected relay. In RF protocol, different codebooks are used by the source and the relay to forward the source message secretly. For each scheme, we derive exact and asymptotic closed-form expressions of secrecy outage probability (SOP), non-zero secrecy capacity probability (NzSCP) in both independent and identically distributed (i.i.d.) and independent but non-identically distributed (i.n.i.d.) networks. Moreover, we also give a unified formula in an integral form for average secrecy capacity (ASC). Finally, our derivations are then validated by Monte-Carlo simulations.

• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.53-57
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• 2007

In this paper, the intelligent estimation algorithm is developed for residual quantity estimate of lithium secondary cell and we suggest the control algorithm to get battery SOC through thermal modeling of electric cell. Lithium secondary cell gives cycle life, charge characteristic, discharge characteristic, temperature characteristic, self-discharge characteristic and the capacity recovery rate etc. Therefore, we make an accurate estimate of the capacity of battery according to thermal modeling to know the capacity of electric cell that is decreased by various special quality of lithium secondary cell. And we show effectiveness through comparison of value as result that use simulation and fuzzy logic.

• 한국미생물·생명공학회지
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• 제16권5호
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• pp.427-431
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• 1988

Pseudomonas testosteroni 6F1의 아닐린 분해에 미치는 이차기질의 첨가효과를 보기 위하여 균생장에 필요한 유도기간과 효소활성유도 정도를 조사하였다. 아닐린만 존재하는 배지에서 P. testosteroni 6Fl은 7시간의 유도기간을 필요로 한데 비하여 쉽게 이용가능한 이차기질을 첨가해준 경우 아닐린 분해에 필요한 유도기간이 1-3시간으로 줄어들었다. 이러한 아닐린 분해 촉진효과는 이차기질과 아닐린이 서로 발리 이용되면서 균체의 생장과 분해효소의 활성유도시기를 앞당겼기 때문이었으며, 이때 아닐린 분해효소의 최종활성 정도는 첨가해준 이차기질에 따라 다르게 나타났다.

• 한국농공학회논문집
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• 제66권2호
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• pp.1-12
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• 2024

In order to integrate two consolidation theories of Terzaghi's consolidation theory and Mesri's secondary compression theory and to identify a model suitable for analyzing stress-strain behavior over time, numerical analysis on consolidation tests were conducted using a modified cam-clay model and a soft soil creep model and the following conclusions were obtained. The results of numerical analysis applying the theory that a linear proportional relationship is established between the void ratio at logarithmic scale and the permeability coefficient at logarithmic scale is better agreement with the result of oedometer test than the results of applying constant hydraulic conductivity. The modified cam-clay model is a model that does not include secondary compression, but the slope of the normal consolidation line corresponding to the compression index of the standard consolidation test includes secondary compression, so the actual settlement curve over time is lower than the predicted value through numerical analysis. It always gets smaller. Other previous studies that applied Terzaghi's consolidation theory to consolidation test analysis showed the same results and were cross-confirmed. The soft soil creep model, which includes secondary compression in the theory, showed good agreement in all sections including secondary compression in the consolidation test results. It was judged appropriate to use a soft soil creep model when performing numerical analysis of soft clay ground.

• Journal of Plant Biotechnology
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• 제33권4호
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• pp.243-248
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• 2006

A optimal procedure for plant production via repetitive secondary somatic embryogenesis in Tilia amurensis is described. Somatic embryos were induced directly from the culture of zygotic embryos on medium with 1.0 mg/l 2,4.-D. Repetitive secondary somatic embryos formed on the surface of the cotyledons and hypocotyls except for the radicles when explants of somatic embryos were cultured on medium with 4.0 mg/l 2,4-D. The highest frequency of secondary embryo-genesis was obtained in the cotyledons (90%) and hypocotyls(83.33%) on MS medium with 1.0 mg/L 2,4-D. The average number of secondary embryos per explant was 25.74 in cotyledon and 24.92 in hypocotyl. When the cotyledon and hypocotyl segments from somatic embryos at different developmental stages were cultured on MS medium with 1.0 mg/L 2,4-D, the highest frequency of secondary embryogenesis was obtained from late cotyledonary secondary embryos. Somatic embryos were transferred to MS basal medium and then they germinated within 2 to 4 weeks of culture. Germinated somatic embryos grew normally into plantlets on WPM medium, producing new shoots. The converted plantlets were acclimatized on artificial soil mixture. These results indicate that the repetitive secondary somatic embryogenesis in T amurensis can offer the possibility to use in vitro culture system for the micropropagation.

• Journal of Information Technology Applications and Management
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• 제23권3호
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• pp.25-34
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• 2016

Often we receive misled conclusion in the research if properly variables are not analyzed. In different functional issues of management it is very essential that all the latent and observed variable are properly understood so management decisions will be relevant and effective. The objective of this paper is to investigate the use of different multivariate tools for analyzing in the management research : applied or basic. The sources of data is primary as well as secondary. The primary includes the observation of different research articles of the proceedings of different conferences. And the secondary includes different publications related to multivariate analysis. The study has revealed the reasons of not using such tools of research. The preliminary finding reveals that most of the researches do not use such analytical tools in a comprehensive manner. Carelessness in design while fixing the design aspect is the main reasons of not using appropriate design.