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        검색결과 326

        81.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As a preliminary study for the effective development of a genre-focused English learner corpus, this article aims to investigate most frequent error types and their frequencies in English emails written by undergraduate freshmen in South Korea. Data for this study include English emails of 86 Korean students majoring in humanities or social science in a university located in Daegu. With the rise of Internet, ESL/EFL education has witnessed a growing interest in teaching email usage in composition courses, as it provides a variety of opportunities to evaluate language abilities including interpersonal and pragmatic abilities. The present article revealed that the most frequent error type was concerned with style, such as capitalization (28.7%) and punctuation (7.8%), which was followed by determiner deletion (6.3%), genre convention such as closing (3%), countability of nouns (3%), and verb choice (2.7%). Different error types and frequencies were identified according to different English proficiency levels (Korean SAT and TOEIC), which evidenced the need to include the English proficiency level annotation in the corpus design and to focus on different types of errors in class in accordance with learners’ proficiency levels.
        6,600원
        83.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The physical characteristics of gluten-free rice bread, commercial rice as well as wheat bread marketed in Korea were delineated, a sensory descriptive analysis performed, and a consumer acceptability study conducted. Both the specific gravity and color of gluten-free rice bread were higher than those of commercial rice and wheat bread. The sensory descriptive analysis revealed that the adhesiveness, fracturability, fermentation odor, and the powdery mouthfeel of gluten-free rice bread were higher than those of commercial rice and wheat bread. In contrast, the sweet odor, sweetness, egg taste, butter taste, and milk taste of gluten-free rice bread were lower than those of commercial rice and wheat bread. The consumer acceptability results revealed differences regarding odor, appearance, taste, texture, and overall acceptance between a blind test and an informed test of gluten-free rice bread, commercial rice, and wheat bread. The consumer acceptability findings were associated with those of the sensory descriptive analysis. In overall, the results indicated that the quality of gluten-free rice bread can be improved by controlling the decrease of adhesiveness, fracturability, and powdery mouthfeel.
        4,000원
        84.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the chemical composition of Petasites japonicus (S. et Z.) Maxim essential oil. During the period 2011~2013, P. japonicus (S. et Z.) Maxim plant was investigated for composition of the essential oil. Chemical composition and characteristic compounds of the essential oils from the aerial parts of the plant according to the crop year studied. The essential oils consisted of sesquiterpene compounds, which were the most abundant components. Samples collected in 2011 were found to be richer in oxygenated sesquiterpenes, while samples collected in 2012 and 2013 were richer in diterpene alcohols and sesquiterpene hydrocarbons, respectively. Ninety-two compounds were identified in the P. japonicus (S. et Z.) Maxim essential oil of 2011, and caryophyllene oxide (20.49%), β-caryophyllene (10.28%), β-bisabolene (6.80%), and alloaromadendrene (6.50%) were the major compounds. Seventy-four compounds were identified in the plant essential oil of 2012, and phytol (17.22%), α-farnesene (15.31%), α-caryophyllene (9.93%), and β-caryophyllene (6.12%) were the major compounds. Ninety-two compounds were identified in the plant essential oil of 2013, and α-farnesene (22.42%), α- caryophyllene (21.49%), pentadecane (15.35%), and germacrene (5.70%) were the major compounds. The content of most of the chemical constituents varied significantly with different harvesting time. The content of α-caryophyllene and caryophyllene oxide was increased significantly from 2011 to 2013. The content of α-caryophyllene and isocaryophyllene was decreased significantly from 2011 to 2013.
        4,000원
        85.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.
        4,000원
        86.
        2017.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.
        4,000원
        87.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate design factors of the electrolysis reactor through the CFD(computational fluid dynamics) simulation technique. Analyses of velocity vector, streamline, chloride ion concentration distribution showed differences in flow characteristics between the plate type electrode and the porous plate type electrode. In case of the porous plate type electrode, chlorine gas bubbles generated from the anode made upward density flow with relatively constant velocity vectors. Electrolysis effect was more expected with the porous plate type electrode from the distribution of chloride ion concentration. The upper part of the electrolysis reactor with the porous plate type electrode had comparatively low chloride concentration because chloride was converted to the chlorine gas formation. Decreasing the size and increasing total area of rectifying holes in the upper part of cathodes, and widening the area of the rectifying holes in the lower part of cathodes could improve the circulation flow and the efficiency of electrolysis reactor.
        4,000원
        88.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, refined finite element (FE) analyses intended to evaluate the capacity of the existing water purification plant structures against seismic force are conducted with an aim to predict possibility generating tension crack and compression crushing. The FE models for three types of main plant structures were constructed to take ground condition, boundary condition, and water interaction into consideration for advanced simulation. The nonlinear dynamic analyses were performed by using ground motion data which have been used for seismic design. Both compression crushing and tention crack, which are distributed over concrete plant structures during peak ground acceleration (PGA), are investigated by analyzing failure possibility controlled with the strain limits. After observing FE analysis results, it is possible to predict tenstion cracking which can be found at some parts of the main structure.
        4,000원
        89.
        2016.10 구독 인증기관·개인회원 무료
        This study investigates the safety and life during the fatigue load by the configuration of seat frame. On back frame at seat frame, the life and damage are analyzed. The deformation and equivalent stress are compared with each other through the vibration analysis, The result of this study through the analysis can be applied to develop the automotive seat frame with durabilty and safety.
        90.
        2016.10 구독 인증기관·개인회원 무료
        In the present study, we analyzed ecological functional groups of diverse hymenopteran families from five different vegetation stands in the Gwangneung forest. Hymenopterans were collected using three different traps from March to October 2015. Pollinators were a dominant group from March to May and declined significantly after that period. Parasitic group made major peaks from April to May and made another small peak in August. Predatory group reached to a peak in April and July respectively but appeared to be active even in October when all the other groups mostly disappeared. The vegetative communities were ordinated with the hymenopteran family assemblages using the Nonmetric multidimensional scaling (NMDS). The result of NMDS analysis showed that the community structure of the hymenopteran functional groups from the Quercus rubra stand is different from those of the other stands.
        91.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        무당벌레(Harmonia axyridis)는 종내에서 초시색상패턴이 매우 다양하게 존재한다. 본 논문에서는 서로 다른 색상패턴의 무당벌레를 대상 으로 amplified fragment length polymorphism (AFLP)을 실시하여 무당벌레의 초시색상 패턴간 유전형질의 차이를 확인하고자 하였다. 총 28 개의 프라이머 조합으로 실험을 실시한 결과, 총 2,741 개의 밴드가 검출되었다. 그 중 20 개의 밴드(S1-S20)만이 특정 색상패턴에서 나타났다. 이들 가운데 9 개의 밴드를 색상에 연관된 AFLP 후보 지표로 선발하였다. 밴드 가운데 S1과 S2, S20은 Succinea 1, 2 변이형에 공통적으로 나타났으며, S3와 S5는 Conspicua 변이형에 특이적이었다. 또한 S13는 Spectabilis 변이형에, S15와 S18, S19는 Succinea 2 변이형에 특이적이었다. 특정 색상패턴에만 나타나는 9 개의 AFLP 지표들은 cloning을 통해 염기서열 분석을 실시하였고, GenBank를 이용해 다른 염기 서열과 비교를 해보았지만 아무런 상동성도 찾을 수가 없었다. 무당벌레 종 내 유전적 다양성을 평가한 결과, Spectabilis가 Conspicua보다 Succinea 변이형에 높은 유사성을 보였다. 색상에 연관된 AFLP 후보 지표를 기준으로 sequence characterized amplified region (SCAR) 지표로 변환하여 9 개의 AFLP 분자지표들 가운데에서 5 개만이 SCAR 지표로 전환될 수 있었으며, 이를 통해 AFLP 지표가 무당벌레의 색상과 연관되어 있는지 확인할 수 있었다.
        4,300원
        92.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze physiological reactions and visual preferences for lawn and flowerbed preferred by mental patients, and green space which is highly related with healing effects. Subjects were 25 mild cases of schizophrenia, who on the recommendation of their doctor, resided in psychiatric hospitals located in Jeollabuk-do, Korea. The survey was carried out in August 2010. The subjects were shown computer graphic simulations by a beam projector, and then brain wave and preferences were measured. In regards to physiological responses, the separate arrangement of tree cluster promoted a sense of stability and vitality, simultaneously. In the aspect of visual preferences, just one mass was preferred. The natural landscape planting pattern was visually preferred. There was a difference in preferences for the planting proportion of evergreen and deciduous trees in the leaf-fall and leaf-color seasons, but when both of them are taken into consideration, it is advisable that 75% of trees planted be occupied by evergreens to encourage emotional stability. The higher the ratio of tree to a lawn, the higher the visual preference. The ratio of 1:1 or 1:0.5 between a lawn and trees is advisable if the physiological effect is considered, but creating a lawn alone should be avoided. With regard to color preferences for the flower bed, orange was visually preferred. Pink was desirable to create a sense of emotional stability, and red to physiologically revitalize the subjects.
        4,900원
        93.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, solid solution heat treatment of consolidated nickel-based superalloy powders is carried out by hot isotactic pressing. The effects of the cooling rate of salt quenching, and air cooling on the microstructures and the mechanical properties of the specimens are analyzed . The specimen that is air cooled shows the formation of serrated grain boundaries due to their obstruction by the carbide particles. Moreover, the specimen that is salt quenched shows higher strength than the one that is air cooled due to the presence of fine and close-packed tertiary gamma prime phase. The tensile elongation at high temperatures improves due to the presence of grain boundary serrations in the specimen that is air cooled. On the contrary, the specimen that is salt quenched and consists of unserrated grain boundaries shows better creep properties than the air cooled specimen with the serrated grain boundaries, due to the negative creep phenomenon.
        4,000원
        94.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korea is part of a region of low to moderate seismicity located inside the Eurasian plate with bedrock located at depths less than 30 m. However, the spectral acceleration obtained from site response analyses based on the geologic conditions of inland areas of the Korean peninsula are significantly different from the current Korean seismic code. Therefore, suitable site classification scheme and design response spectra based on local site conditions in the Korean peninsula are required to produce reliable estimates of earthquake ground motion. In this study, site-specific response analyses were performed at more than 300 sites with at least 100 sites at each site categories of SC, SD, and SE as defined in the current seismic code in Korea. The process of creating a huge database of input parameters - such as shear wave velocity profiles, normalized shear modulus reduction curves, damping curves, and input earthquake motions - for site response analyses were described. The response spectra and site coefficients obtained from site response analyses were compared with those proposed for the site categories in the current code. Problems with the current seismic design code were subsequently discussed, and the development and verifications of new site classification system and corresponding design response spectra are detailed in companion papers (II-development of new site categories and design response spectra and III-Verifications)
        4,000원
        95.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        원자력발전소에서 전기를 생산하고 난 후 발생하는 사용후핵연료 또는 이들 사용후핵연료의 재처리/재활용 공정으로부터 발생하는 고준위폐기물은 인간환경으로부터 안전하게 장기간 격리시켜야 한다. 최근 심부시추공 굴착기술의 획기적인 발전 으로 인하여, 방사성폐기물의 심부시추공 처분기술에 대한 연구가 의미 있게 진행되고 있다. 본 논문에서는 이러한 심부시추 공을 활용하여 고준위 방사성폐기물을 지하 3~5 km 심도에 격리시키는 심부시추공 처분기술의 국내 적용 가능성을 분석하 기 위하여 국내 심부 지하환경 특성에 대하여 예비분석 하였다 이를 위하여, 미국 및 유럽권 국가 연구사례와 기술개발 현황 을 검토하고, 실제 국내의 심부 지질조건을 검토하기 위하여 고지열 분포지역에 개발 중인 지열 탐사공을 대상으로 3~4 km 심도까지의 암석, 지온 등 특성 자료를 수집, 분석하였다. 결정질 암반 심도 및 지온경사 등 분석 결과와 국내 발생 사용후 핵연료를 바탕으로 심부시추공 처분시스템 구성요소인 처분용기, 밀봉시스템 등에 대하여 예비단계의 개념을 제안하였다.
        4,000원
        98.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the current regulations to be adequate in industrial site have to be renew in order to prevent the fatal injuries by mobile cranes. Fatal injury analyses were conducted with several accident cases by the mobile cranes. For each accident, the causes of the injuries were examined and proper safety measures were proposed. This study proposed a revision of the standard guideline as an accident prevention measures through in-depth analysis of fatal accidents. First, fatality rate per 10,000 persons by the mobiles cranes was 0.57 in 2011. Second, the in-depth analysis of the mobile crane accidents showed that the main factors of the accidents were the overturn of mobile crane, the fracture of connection part between mobile crane boom and rope, the breaking of rope and the misunderstanding over the signal between a mobile crane driver and workers around a mobile crane. Third, the order of high defection of connecting parts was bucket bolt, bracket and extension parts. Fourth, since there were several cases of overturn of mobile crane by itself in the in-depth analysis of the mobile crane, the over slop-proof device was proposed as the main alternative in this study. Fifth, the revision of standards of safety factor that shall be more than 10, of connecting parts of mobile crane was proposed.
        4,000원
        99.
        2016.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study suggests a prediction model of ground motion spectral shape considering characteristics of earthquake records in Korea. Based on the Graizer and Kalkan’s prediction procedure, a spectral shape model is defined as a continuous function of period in order to improve the complex problems of the conventional models. The approximate spectral shape function is then developed with parameters such as moment magnitude, fault distance, and average shear velocity of independent variables. This paper finally determines estimator coefficients of subfunctions which explain the corelation among the independent variables using the nonlinear optimization. As a result of generating the prediction model of ground motion spectral shape, the ground motion spectral shape well estimates the response spectrum of earthquake recordings in Korea.
        4,000원
        100.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yield per recruit model is the most popular method for fisheries stock assessment. However, stock assessment using yield per recruit model can lead to recruitment overfishing as this model only considers the maximum yield per recruit without spawning biomass for reproduction. For this reason, spawning biomass per recruit model which reveals variations of spawning stock biomass per fishing mortality (F) and age at first capture (tc) is considered as more proper method for stock assessment. There are mainly two methods for spawning biomass per recruit model known as age specific selectivity method and knife– edged selectivity method. In the knife–edged selectivity method, the spawning biomass per recruit has been often calculated using biomass per recruit value by multiplying the maturity ratio of the recruited age. But the maturity ratio in the previous method was not considered properly in previous studies. Therefore, a new method of the knife–edged selectivity model was suggested in this study using a weighted average of the maturity ratio for ages from the first capture to the lifespan. The optimum fishing mortality in terms of F35% which was obtained from the new method was compared to the old method for small yellow croaker stock in Korea. The value of F35% using the new knife–edged selectivity model was 0.302/year and the value using the old model was 0.349/year. However, the value of F35% using the age specific selectivity model was estimated as 0.320/year which was closer to the value from the new knife–edged selectivity model.
        4,000원
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