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        검색결과 91

        21.
        2020.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        FDM 3D printing structures have rough surfaces and require post-treatment to improve the properties. Fumigation is a representative technique for removing surface unevenness. Surface treatment by fumigation proceeds by dissolving the surface of the protruding structure using a vaporized solvent. In this study, 3D printed PVB outputs are surface-treated with ethyl-alcohol fumigation. As the fumigation time increases, the surface flattens as ethanol dissolves the mountains on the surface of PVB and the surface valleys are filled with dissolved PVB. Through the fumigation process, the mechanical strength tends to decrease, and deformation rate increases. Ethanol vapor permeates into PVB, widening the distance between chains and resulting in weak bonding strength between chains. In order to confirm the effect of fumigation only, an annealing process is performed at 80 oC for 1, 5, 10, 30, and 50 minutes and the results of the fumigation are compared.
        4,000원
        22.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 자연재해에 대한 집계구 단위의 인명 취약성 지수 평가 방법론을 제안하였다. 인명 취약성 지수는 자연재해에 대한 인명의 리스크 지수(Risk Index) 평가 시 필수적으로 요구되는 것으로써 인명의 노출도(Exposure)와 민감도(Sensitivity)가 고려된 취약성 대리변수의 결합으로 평가될 수 있다. 본 연구에서는 경주시를 평가 시범지역으로 선정하여 자연재해에 대한 인명 취약성 지 수 방법론을 적용하였다. 자연재해 인명 리스크와 관련된 문헌조사를 통하여 6개의 취약성 대리변수(인구밀도, 직업, 취약계층, 성별, 교육수준, 외국인)가 선정되었으며, 선정된 취약성 대리변수는 기 설정된 점수화 기준에 따라 평가치가 산정된 후 정규화 방법에 따라 무차원화 되었다. 각각의 취약성 대리변수를 결합하기 위한 가중치는 인명 취약성 지수 관련 문헌에서 적용된 가중치를 메타분석(Meta- Analysis)하여 파악되었다. 인명 취약성 지수를 평가하기 위해 필요한 인구 통계자료 데이터베이스는 통계청에서 제공하는 집계구별 인구 통계자료를 기초로 구축되었다. 경주시에 대한 인명 취약성 지수 평가의 경우, 인명에 대한 노출도 및 민감도가 높은 공동주택 단 지에서 가장 취약할 수 있음을 확인하였다. 본 연구에서 제안된 취약성 지수 평가 방법론은 집계구 단위 지역에서의 자연재해 리스크 를 신속하게 평가할 시 활용가능하다.
        4,000원
        23.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study investigated how task types such as input or output could affect Korean EFL learners’ vocabulary learning at both short- and long-term periods after treatment. Forty two college students in Korea were randomly assigned to one of the four tasks. Based on Involvement Load Hypothesis, each task induced the same or different involvement loads: Read without glossary (Input), Gap with glossary (Input & Output), Gap without glossary (Input & Output), and Sentence and write (Output). Receptive and productive vocabulary knowledge was measured right after the treatment and a month later. The output-oriented tasks were found to be more effective than the input-oriented tasks regardless of type of vocabulary knowledge. The current study concluded that modalities such as input or output other than task-induced involvement load can contribute to Korean EFL learners’ vocabulary learning. The pedagogical discussion will be made at the conclusion.
        5,700원
        24.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the relative effects of input-based versus output-based activities on the learning of English unaccusative constructions. A total of 73 high school students were randomly assigned into two experimental groups and one control group. Of the two experimental groups, the input-based input enhancement group (IE group) experienced a reading passage with the learning targets visually enhanced. The output-based dictogloss group (DG group) performed the dictogloss task with the identical passage given to IE group. The control group (CG group) did not experience the learning targets at all. Results showed that IE group statistically significantly outperformed CG group both at the immediate and the delayed posttests, while there was no significant difference between IE group and DG group. In terms of the generalizability of the learned knowledge, however, it was DG group that outperformed CG group at the immediate posttest. Again, there was no difference between IE group and DG group. More detailed findings are provided, along with some implications for English classrooms in Korea.
        5,700원
        25.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Piezoelectric energy harvesting technology is attracting attention, as it can be used to convert more accessible mechanical energy resources to periodic electricity. Recent developments in the field of piezoelectric energy harvesters (PEHs) are associated with nanocomposites made from inorganic piezoelectric nanomaterials and organic elastomers. Here, we used the BaTiO3 nanoparticles and piezoelectric poly(vinylidene fluoride) (PVDF) polymeric matrix to fabricate the nanocomposites-based PEH to improve the output performance of PEHs. The piezoelectric nanocomposite is produced by dispersing the inorganic piezo-ceramic nanoparticles inside an organic piezo-polymer and subsequently spin-coat it onto a metal plate. The fabricated organic-inorganic piezoelectric nanocomposite-based PEH harvested the output voltage of ~1.5 V and current signals of ~90 nA under repeated mechanical pushings: these values are compared to those of energy devices made from non-piezoelectric polydimethylsiloxane (PDMS) elastomers and supported by a multiphysics simulation software.
        4,000원
        27.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 한국의 연구개발투자가 제조업구분에 따른 파급효과들을 산업연관분석을 이용하여 분석하고 있다. 연구 방법은 2010∼2014년 국내 산업연관표 상에서 연구개발투자 부문을 외생화하고, 경제협력개발기구(OECD)의 기술수준 분류표에 입각하여 기술수준별로 제조업을 분류하여 연구개발투자가 미치는 생산유발효과와 부가가치유발효과를 분석하였다. 분석결과, 연구개발투자의 기술수준별 제조업 구분에 따른 생산유발효과는 중고기술과 중저기술에 속한 제조업에서 높은 것으로 나타났으며, 부가가치유발효과 역시 중고기술 제조업에서 높은 것으로 나타났다. 반면 연구개발투자가 가장 많은 고기술제조업에서 생산유발효과와 부가가치유발효과가 상기 2부문보다 낮은 것으로 분석되었다. 이러한 결과들은 한국 제조업이 연구개발투자를 통해 기술수준의 제고를 달성하고 이를 산업구조의 고도화로 이어간다는 품질사다리론과 연계되지 않았음을 의미한다. 이러한 분석결과로부터 한국의 연구개발투자가 고기술제조업의 생산유발과 부가가치효과의 증대를 위해 구조조정이 필요하다는 시사점을 얻었다. 본 논문은 산업연관표의 구조적 특성으로 인해 연구개발투자의 시차를 고려하지 못한 한계를 안고 있다.
        5,700원
        28.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the study is to provide an analysis of lexical, syntactic, and cohesive features, which were utilized to distinguish written products of L2 writers in the individual writing task from those in the group writing one using Coh-Metrix. In addition, the study attempts to explore linguistic differences in their written outputs with regard to their L2 proficiency and the correlationships between receptive lexical knowledge and productive lexical knowledge. A total of 105 Korean university students participated in this study. Results show that L2 learners’ written outputs varied in several variables used in this analysis such as lexical diversity and word frequency. L2 learners in the individual task yielded more cohesive texts, and they were able to incorporate more difficult words into their written products. Meanwhile, learners in the group task produced longer texts with using more logical and temporal connectives. When proficiency level was considered, L2 learners at the advanced level did not produce more cohesive texts, but instead produced more syntactically complex texts. The scores of productive lexical knowledge in the individual task positively correlated with those of receptive lexical knowledge from two different vocabulary tests. Meanwhile, the scores of productive lexical knowledge in the group task did not yield the similar results. The results implied that Korean university learners in the individual task were more task-oriented and produced a better written output.
        6,400원
        29.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        선박에서 배출되는 환경오염물질 저감 및 연료 소비를 줄이기 위한 다양한 연구가 진행되고 있다. 이에 따라 기존의 전력망과 신재생에너지를 연계 시킬 수 있는 직류배전시스템의 한 부분인 전력변환시스템에 대한 연구가 활발히 이루어지고 있다. 현재 전력변환 장치로 주로 사용되고 있는 다이오드 정류기는 부하의 입력전류에 많은 저차고조파가 포함되어 공급전압의 왜곡을 초래하고 전체시스템 의 전력품질을 저하시킨다. 일정하지 않은 출력 전압파형은 발전기, 부하기기 등에 오작동 유발 및 인버터 단의 스위칭 소자에 영향을 미 치며 스위칭 손실을 증가 시킨다. 본 논문에서는 AFE(Active Front End) 방식 PWM(Pulse Width Modulation) 정류기의 직류출력, 입력 전원의 역률 및 총고조파왜형률(Total Harmonic Distortion)을 개선하기 위해서 PLL회로를 사용한 제어기를 설계하였고, 시뮬레이션 결과 직류 출력 전압 파형과 입력전원의 역률이 기존 보다 개선되었으며 총고조파왜형률 또한 IEEE Std514-2014 규정에 적합한 결과를 얻을 수 있었다.
        4,000원
        30.
        2017.10 구독 인증기관·개인회원 무료
        The Joint Load Transfer (LTE) is important for both design and evaluation of concrete pavements. Numerous researches have been published to determine different factors that affect the load transfer efficiency through Finite Element Method (FEM) and field measurements. Most of these researches are using static analysis. Previous study pointed out the weakness of the assumption of this analysis and successfully differentiate the dynamic stress-based LTE with static stress-based LTE through FEM. Usually deflection based LTE(w) is being evaluated in the field through Heavy Weight Deflectometer (HWD). This test is a dynamic test which typically uses peak displacement and assumed to be static displacement when similar amount of static loading is applied. The calculation of LTE(w) in the field involves the ratio of the peak displacement of unloaded to loaded slab. Using this LTE(w) calculation, there were instances that high values were obtained from spalled joints and joints with wider opening. This study attempts to provide a better characterization of the condition of the joint. A time-based LTE(t) using the time delay were investigated and correlated with the current LTE(w) using a 24 hour measurement of deflection from asphalt and concrete pavement, with a 3-hour interval done in Gimpo International Airport. Wider values of LTE(t) were obtained while the deflection-based LTE(w) shows almost similar values. The time-based LTE(t) shows better relationship with the physical condition of the joint than LTE(w). It shows that LTE(t) can characterized the condition of the joint. This result will be used for further study to improve the measurement of load transfer efficiency of concrete pavement joints
        31.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 초고층건축물의 풍진동 모니터링을 위한 시스템식별기법의 현장적용성을 평가하였다. 실제 아웃리거-벨트월 을 횡력저항 시스템으로 가지는 실제 63층 RC구조물을 대상으로 상시 및 강풍시 응답을 모니터링하였으며, 진동수영역분해(FDD), 랜덤감소(RDT)기법, 부분공간시스템식별(SSI)법을 사용하여 진동특성을 식별하였다. 건물의 평면이 정방형이고, 두 개의 횡방향 모드의 진동수는 매우 유사하였다. 모든 식별기법에서 태풍과 같이 강한 외력이 존재할 경우 뿐만 아니라 상시미진동 에서도 구조물의 모드 특성을 식별할 수 있었다. 현장에서의 적용성 평가결과, 계산속도는 FDD가 가장 빨랐으며, RDT가 가장 간단한 프로그래밍 절차를 가지고 있음을 확인하였다.
        4,000원
        32.
        2016.07 구독 인증기관 무료, 개인회원 유료
        The increasing competition in recent years made more and more firms regard strategic alliance as an important alternative and solution to respond to fierce competition. As a kind of system arrangement among firms, the concept of strategic alliance was first proposed by Hopland and Nigel in the early 1980s, who defined strategic alliance as the collaboration mode in which two or more firms, aiming at joint-owned both market and resources, formed the kind of cooperation to enhance advantages, share risk or cost, and also mutual flow of production factors via different kinds of contracts or agreement. However, even before this definition, many firms have already begun their alliance strategies practices. As a cooperative form, strategic alliance, no matter its specific types, becomes one key choice for firms to acquire, maintain and enhance their market shares and positions. Shrader (2001) found that collaboration to foreign firms become key methods for newly-founded firms and small firms to enter foreign markets, which can bring these firms with suitable knowledge and market information, making these firms expand even faster with lower costs and market risks. The enhancing pace of globalization and internationalization triggered firms’ attentions to external markets, Archibugi and Iammarino (2002) found that fierce changes in internal market forced firms to expand their market and product scopes, making more and more firms realize product and R&D internationalization by searching, choosing and collaborating with foreign firms. Dong and Glaister (2006) found Chinese firms cared more about market positions, international expansion and technology exchanges, while foreign firms tended to enter to Chinese market and learn how to operate in China via strategic alliances. Although, many scholars brought out managerial practices of firms’ strategic alliances, and had already formed theoretical foundations, researches related to market orientation, especially how alliance firms establish and realize their strategic goals and performance goals under market motivation is still lack of studies. In reality, the mechanism how firms’ alliance intention transformed into their strategic or performance goals is still in the black box. Taken alliance firms as research objectives, this paper tends to explore how firms constructed strategic alliance due to market-orientation realize their strategic or performance goals via choice of patent strategies. We introduced patent strategies to establish the matching model, to analyze how firms market orientation influence choices of patent strategies, and their mutual effects on firms innovative performance, in hope to provide to the future studies and managerial practice how firms can choose the reasonable and effective alliance partners according to their own strategic and performance goals. Based on differentiation of market access and market extension motivation, we pointed out that, in order to realize the transformation from alliance motivation to innovation performance, alliance firms had to choose and determine among a set of practical and operational plans. Patent strategies, as a kind of operational plan, were conducive to transformation from alliance motivation to innovation performance. With the framework of market motivation, patent strategy and firms innovative performance, we put forward the hypotheses on how market motivation affect firms’ choices of patent strategies, and also the joint effects of market motivation and patent strategies on firm innovative performance. We selected alliance firms in IT industry as samples, with data from Cooperative Agreements and Technology Indicators Database, USPTO and R&D Scoreboard released by Department for Business, Innovation & Skills of UK, we empirically tested effects of market motivation on choices of patent strategies, and also effects of market motivation and patent strategies on firms innovative performance. Results showed that: different market positions led to differentiated motivations and patent strategies in their strategic alliances, firms with relatively weak market positions tend to pursue strategic profile of patent defensive and leveraging strategies under market access motivation, while firms with strong positions would like to implement patent proprietary and leveraging strategies in market extension motivation. The implementation of patent defensive and leveraging strategies under market access motivation enhanced innovation efficiency of the firms with weak market positions. Since these firms focused more on market positions and opportunities, their market capitalization tended to improve, but the motivation and utilization of patent strategies had no effect on patent output. Similar to these firms, the ones with stronger market position were inclined to strengthen their market opportunities and improve their market capitalization. Results indicated that because of their stronger market positions, these firms showed lower awareness of innovation efficiency and their emphasis on patent output was not high either, which then led to the fact that both market extension motivation and patent strategies used had no effects on firms innovative performance measured by innovation efficiency or patent output.
        3,000원
        33.
        2015.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In photovoltaic power generation where minority carrier generation via light absorption is competing against minority carrier recombination, the substrate thickness and material quality are interdependent, and appropriate combination of the two variables is important in obtaining the maximum output power generation. Medici, a two-dimensional semiconductor device simulation tool, is used to investigate the interdependency in relation to the maximum power output in front-lit Si solar cells. Qualitatively, the results indicate that a high quality substrate must be thick and that a low quality substrate must be thin in order to achieve the maximum power generation in the respective materials. The dividing point is 70 μm/5 × 10−6 sec. That is, for materials with a minority carrier recombination lifetime longer than 5 × 10−6 sec, the substrate must be thicker than 70 μm, while for materials with a lifetime shorter than 5 × 10−6 sec, the substrate must be thinner than 70 μm. In substrate fabrication, the thinner the wafer, the lower the cost of material, but the higher the cost of wafer fabrication. Thus, the optimum thickness/lifetime combinations are defined in this study along with the substrate cost considerations as part of the factors to be considered in material selection.
        4,000원
        34.
        2015.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The present study investigates the effect of peer evaluation tasks on learners’ noticing and production of prominence. Attention is placed on the students’ noticing episodes during the task, and whether the student utilizes what is noticed into their re-recordings to achieve more intelligible speech. The results reveal that the students directed their attention to the features of prominence, with metalinguistic reflections evident in their transcriptions and exchanges of evaluative comments. The students’ first and second recordings were then assessed by four native speakers based on five criteria: comprehensibility, rhythm, stress, intonation, and perceived naturalness. The ratings indicated that the students’ second recordings were evaluated lower in intelligibility and were regarded as being unnatural, forced, and overly exaggerated in their production of prominence. Lastly, qualitative analyses of the audio revealed that the post-task recordings involved an increased frequency of stress production, but the exaggerated prosodic qualities in pitch, elongation, and volume may have been contributing factors leading to lower intelligibility.
        6,000원
        35.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Despite the increasing interest in noticing by second language (L2) learners during the output process, little attention has been given to child L2 learners’ noticing and output. Thus, the present study investigated what child L2 learners of different English proficiency levels noticed as they composed a text and received written corrective feedback (WCF) (error correction vs. models), and how they incorporated the noticed features into their revised texts. Data were collected from twenty-six child pairs throughout three stages (composition, comparison, and revision stages) and note-taking was employed as a means of measuring learner noticing. It was found that learners were able to initiate noticing on their own when composing texts, and that highproficiency learners tended to attend to grammatical problems more frequently than medium/low-proficiency learners. WCF played a facilitative role in leading learners to notice, and their attention to language was mediated differently by different types of WCF. Learners incorporated the noticed features into their revisions, and textual revisions were mostly lexical. Error correction (EC) triggered more grammatical revisions, while the model text helped learners to notice something beyond what they could produce on their own. These findings suggest a facilitative role for output and WCF as a means of learner noticing, and the different roles of EC and model texts.
        6,100원
        36.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A shared tuned mass damper (STMD) was proposed in previous research for reduction of dynamic responses of the adjacent buildings subjected to earthquake loads. A single STMD can provide similar control performance in comparison with two traditional TMDs. In previous research, a passive damper was used to connect the STMD with adjacent buildings. In this study, a smart magnetorheological (MR) damper was used instead of a passive damper to compose an adaptive smart STMD (ASTMD). Control performance of the ASTMD was investigated by numerical analyses. For this purpose, two 8-story buildings were used as example structures. Multi-input multi-output (MIMO) fuzzy logic controller (FLC) was used to control the command voltages sent to two MR dampers. The MIMO FLC was optimized by a multi-objective genetic algorithm. Numerical analyses showed that the ASTMD can effectively control dynamic responses of adjacent buildings subjected to earthquake excitations in comparison with a passive STMD.
        4,000원
        37.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is to estimate the economic effect of benefits of the R&D and recreational fishing as well as input-output analysis in the Tae-an Trial Sea Farm Project(TTSFP). We use B/C model to indicate the effects of economic valuation. B/C analyses model consists of Benefit Cost Ratio(BCR), Net Present Value(NPV) and Internal Ration of Return(IRR). Using 5.5% discounting rates and the survey data, the sub-models show economically feasible in the all of analysis and analyzed the results as follows. NPV is 42,147 million won, BCR is 3.29 and IRR is 34.30%. This study attempts to apply input-output(I-O) analysis in connecting the economic effect of TTSFP. I-O model was constructed, focusing on three effects; the production-inducing effect, the value-added-inducing effect and employment-inducing effect. There are positive effects on economic value and job creation in Tae-an and Nation.
        4,200원
        38.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recognizing the importance of output and noticing in the second language acquisition, the present study investigated whether model writings and noticing-triggering activities can serve as one form of written feedback to learners’ writing. Particularly, it was interested in whether two different noticing-triggering activities would have different effects on learners’ noticing and incorporation in immediate and delayed revisions. To this end, 93 university students in three English composition classes in Busan were asked to take part in four-staged picture-cued narrative writing task (i.e., drafting, comparison, immediate revision, and delayed revision). The three classes engaged in different activities (i.e., note-taking, underlining, or reading) while they were comparing their own writing and the given models. The results indicated that models as written feedback have led learners to notice linguistic forms that they have previously found problematic or have not thought of as problematic. Furthermore, the note-taking activity in the comparison stage seemed to help learners better incorporate the linguistic forms included in the subsequent input.
        6,400원
        39.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기술연관분석으로 단기 상용화를 위한 기술개발과제에 투입된 기술간 융합현황을 분석하였다. 기술연관분석은 산업구조분석의 체계를 기술기획 분야에 적용한 것이다. 본 사례는 기술연관분석을 활용하여 기술과 제품 간 연관도를 중심으로 분석하였으며 분석대상은 중소기업기술정보진흥원의 ‘’12년 중소기업 융ㆍ복합기술개발사업’에 신청한 401개 과제이다. 분석과정은 다음과 같다. 401개 개별과제에 대해서 투입된 기술은 기술로, 개발과제에서 산출을 제품으로 정의하고 이를 투입과 산출의 행렬로 정리하였다. 투입으로 정의한 기술은 국가과학기술표준분류 상의 소분류를 분류하고, 산출로 정의한 제품은 한국표준산업분류 상의 세세분류로 정의하였다. 즉, 기술을 투입으로, 제품을 산출로 정의하여 기술의 파급도를 분석하였으며 이에 기초하여 기술연관도를 작성하였다분석결과, IT융합에서는 임베디드 S/W의 기술파급도가 가장 높았으며, ET융합에서는 금형의 기술파급도가 가장 높았고 BT융합은 기능성 화장품 개발기술의 기술파급도가 가장 높았다. 전체적으로 IT융합에서 기술파급도가 높은 요소기술이 많았으며, ET융합에서 기술파급도가 높은 요소기술이 작았다. 따라서 기술파급도가 높은 요소기술에 대한 투자가 융합을 활성화하는 데 중요하며 전체적으로 IT분야가 요소기술의 투자 효과가 높을 것으로 판단한다.
        8,300원
        40.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기업의 제품혁신 과정에서 기술협력 활동과 전유성의 확보가 제품혁신성과에 어떠한 영향을 미치는지 살펴보았다. 추가적으로 협력활동과 전유성의 상호작용 효과 (전유성의 조절효과)에 대하여 분석하였다. 과학기술연구원에서 조사한 2010년 한국 제조업의 기술혁신조사 자료를 이용한 실증분석 결과 고객과의 협력활동과 계열사와의 협력활동이 제품혁신에 긍정적인 영향을 미치는 것으로 나타났다. 또한, 전유성의 그 자체로 제품혁신에 긍정적인 영향을 줄 뿐만 아니라 고객과의 협력활동이 제품혁신에 주는 긍정적인 영향을 배가시키는, 다시 말해 제품혁신에서 전유성의 중요성이 확인되었다. 이러한 연구 결과를 바탕으로 제품혁신 성과를 높이기 위한 전략적 시사점을 도출하였다. 제품혁신에서는 기술협력활동뿐만 아니라 전유성의 확보가 혁신성과를 결정하는 중요한 요인이기에 기업에서는 기술협력활동의 활성화 및 기술의 전유성 확보에 힘써야 할 것이며 이러한 전유성의 확보를 위한 기술보호 수단의 전략적 활용에 대한 통찰이 필요하다.
        6,700원
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