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        검색결과 25

        1.
        2023.07 구독 인증기관·개인회원 무료
        Measuring service quality and related key dimensions has been an important problem in Marketing. In this research, we would introduce a smart methodological framework to efficiently identify refined, key sentiment dimensions for measuring the service quality using both traditional survey and unstructured online reviews (natural survey). The proposed framework consists of three parts: (1) steps for preprocessing the unstructured reviews to generate attribute-level sentiments for independent variables (2) Bayesian regression to efficiently identify key groups of correlated attributes and (3) post-hoc analysis for identifying dimensions from the selected groups of correlated attributes and predicting dimension-level effects. Note, the first part of the framework (i.e., preprocessing) is not required for analyzing traditional surveys. Our framework provides two sets of complementing results such as attribute-level effects under the identified dimensions and aggregate dimension-level effects. In the first application study to traditional SERVQUAL data, we successfully validated the proposed framework by comparing the results between our framework and three commonly used existing methods of regression, lasso regression, and factor analysis. In the second empirical application study with the online reviews from a major game review website, STEAM platform, we found that our framework provided a significantly reduced number of key dimensions which were surprisingly efficient for predicting and explaining the service quality ratings, compared with the same set of compared methods in the first study plus the topic model. In particular, with reviews of 2,825 games, three key dimensions of Mechanical playability, Fun in fantasy and Money for value were identified, and we also found that the Mechanical playability could be an important driver of game popularity.
        3.
        2019.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Green BaSi2O2N2:0.02Eu2+ phosphor is synthesized through a two-step solid state reaction method. The first firing is for crystallization, and the second firing is for reduction of Eu3+ into Eu2+ and growth of crystal grains. By thermal analysis, the three-time endothermic reaction is confirmed: pyrolysis reaction of BaCO3 at 900 oC and phase transitions at 1,300 oC and 1,400 oC. By structural analysis, it is confirmed that single phase [BaSi2O2N2] is obtained with Cmcm space group of orthorhombic structure. After the first firing the morphology is rod-like type and, after the second firing, the morphology becomes round. Our phosphor shows a green emission with a peak position of 495 nm and a peak width of 32 nm due to the 4f65d1→4f7 transition of Eu2+ ion. An LED package (chip size 5.6 x 3.0 mm) is fabricated with a mixture of our green BaSi2O2N2, and yellow Y3Al5O12 and red Sr2Si5N8 phosphors. The color rendering index (90) is higher than that of the mixture without our green phosphor (82), which indicates that this is an excellent green candidate for white LEDs with a deluxe color rendering index.
        4,000원
        4.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The 20-kHz ultrasonic irradiation was applied to investigate bacterial inactivation and antibiotic susceptibility changes over time. Applied intensities of ultrasound power were varied at 27.7 W and 39.1 W by changing the amplitude 20 to 40 to three bacteria species (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). By 15-min irradiation, E. coli, a gram-negative bacterium, showed 1.2- to 1.6-log removals, while the gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus, showed below 0.5-log removal efficiencies. Antibiotic susceptibility of penicillin-family showed a dramatic increase at E. coli, but for other antibiotic families showed no significant changes in susceptibility. Gram-positive bacteria showed no significant differences in their antibiotic susceptibilities after ultrasound irradiation. Bacterial re-survival and antibiotic susceptibility changes were measured by incubating the ultrasound-irradiated samples. After 24-hour incubation, it was found that all of three bacteria were repropagated to the 2- to 3-log greater than the initial points, and antibiotic inhibition zones were reduced compared to ones of the initial points, meaning that antibiotic resistances were also recovered. Pearson correlations between bacterial inactivation and antibiotic susceptibility showed negative relation for gram-negative bacteria, E. coli., and no significant relations between bacterial re-survival and its inhibition zone. As a preliminary study, further researches are necessary to find practical and effective conditions to achieve bacteria inactivation.
        4,600원
        5.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Objectives of this study were to identify the hotspot for displacement of the on-line water quality sensors, in order to detect illicit discharge of untreated wastewater. A total of twenty-six water quality parameters were measured in sewer networks of the industrial complex located in Daejeon city as a test-bed site of this study. For the water qualities measured on a daily basis by 2-hour interval, the self-organizing maps(SOMs), one of the artificial neural networks(ANNs), were applied to classify the catchments to the clusters in accordance with patterns of water qualities discharged, and to determine the hotspot for priority sensor allocation in the study. The results revealed that the catchments were classified into four clusters in terms of extent of water qualities, in which the grouping were validated by the Euclidean distance and Davies-Bouldin index. Of the on-line sensors, total organic carbon(TOC) sensor, selected to be suitable for organic pollutants monitoring, would be effective to be allocated in D and a part of E catchments. Pb sensor, of heavy metals, would be suitable to be displaced in A and a part of B catchments.
        4,000원
        6.
        2019.04 구독 인증기관·개인회원 무료
        갈색날개매미충은 현재 급속도로 확산하고 있으며 그 피해는 기하급수적으로 증가하고 있다. 이번 연구는 이러한 갈색날개매미충의 현재와 미래 분포를 CLIMAX와 MaxEnt를 사용하여 예측하였다. 또한 두 개의 프로그램에서 변수 선정은 사용된 환경인자와 갈색날개매미충 발생과의 공간적 상호 관계를 SADIE로 분석하여 사용함으로써 발생에 영향을 주는 요소만을 분석에 이용하였다. CLIMAX의 경우 중국 저장성의 기후 요소와 한국 전역의 기후 요소를 Climate Matching을 사용하였고, MaxEnt의 경우 상관관계 분석과 공간자료 분석에 의해 선정된 11개 환경 요소를 이용하여 갈색날개매미충의 현재 및 미래 분포를 예측하였다. 연구결과 한국 전역은 갈색날개매미충 발생에 적합한 것으로 나타났으며, 한국의 서쪽 지역이 동쪽 지역보다는 상대적으로 발생 적합성이 높았으며 동쪽으로 점차 이동할 가능성이 높은 것으로 나타났다. 이번 연구 결과는 갈색날개매미충의 방제 전략을 구축하는데 도움을 줄 뿐만 아니라 보다 유의미한 종분포 모델 개발을 위해 공간자료 분석의 사용법을 제시하였다.
        7.
        2018.10 구독 인증기관·개인회원 무료
        밤 재배단지에서 갈색날개매미충은 밤바구미, 복숭아명나방, 붉은매미나방과 주요 해충으로 경제적으로 피해를 야기하고 있다. 이에 밤 재배단지에서 2년 동안 갈색날개매미충의 공간적 이동 양상을 분석하기 위해 실험을 수행하였다. 실험은 부여에 위치한 한 밤 재배단지에서 대략 30m 간격으로 임의로 밤나무를 선정, 표지한 후 GPS를 이용 좌표를 구하고 나무당 50cm 가지 2개에 존재하는 갈색날개매미충 알, 약충, 성충의 밀도를 육안 조사하였다. 조사된 결과를 SADIE를 이용해 공간적 상호관계를 분석해 본 결과 알, 약충, 성충 2년 동안 지속적으로 양의 공간적 상호관계를 보였고, 약충 시기를 제외하고는 통계적으로 유의하였다(p < 0.025). 이는 넓은 밤 재배단지에서 갈색날개매미충이 발육단계에 상관없이 특정 지역에서만 집중적으로 발생하고 있다는 것을 의미하며 특정 지역에 집중적인 방제가 필요하다는 것이다. 이러한 결과를 바탕으로 연구된 밤 재배단지에서 갈색날개매미충의 방제 전략이 제안되었다.
        8.
        2018.04 구독 인증기관·개인회원 무료
        밤 재배단지에서 갈색날개매미충은 밤바구미, 복숭아명나방, 붉은매미나방과 함께 경제적 피해를 야기하고 있는 해충으로 2017년 부여 남면 일대에서는 이들 해충에 의해 밤의 상업적 수확을 전혀 할 수 없었던 농가들도 발생하였다. 이에 밤 재배단지에서 갈색날개매미충의 방제 전략 중 하나의 정밀방제 가능 여부를 판단하기 위해 실험을 수행하였다. 실험은 부여에 위치한 한 밤 재배단지에서 대략 30m 간격으로 무작위로 밤나무를 선정, 표지한 후 GPS를 이용 좌표를 구하고 나무당 50cm 가지 2개에 존재하는 갈색날개매미충 알, 약충, 성충의 밀도를 육안 조사하였다. 조사된 결과를 SADIE를 이용해 공간적 상호관계를 분석한 결과 알, 약충, 성충 모두 90% 유의수준에서 공간적 상호관계를 보였다. 이는 넓은 밤 재배단지에서 갈색날개매미충이 발육단계에 상관없이 특정 지역에서만 집중적으로 발생하고 있다는 것을 의미하며 정밀방제가 가능할 것이라고 생각된다. 이러한 결과를 바탕으로 연구된 밤 재배단지에서 갈색날개매미충의 방제 전략이 논의되었다.
        9.
        2016.11 구독 인증기관·개인회원 무료
        분리막 및 다양한 CO2 포집공정들의 연구에 있어, 경제성 평가는 각 공정들을 비교 분석하며 개발된 기술의 경제적 타당성을 검토하는데 중요한 역할을 한다. 본 연구에서는 분리막 기반의 CO2 포집공정에 대한 경제성 분석을 수행하여 그 결과를 살펴보았다. 분리막 공정의 전산모사와 최적화를 위하여 분리막 모델링 및 Aspen HYSYS®를 활용하였으며, 최적화 결과를 바탕으로 CAPEX 및 OPEX를 제시하여 분리막 공정의 경제성 평가를 진행하였다.
        10.
        2016.11 구독 인증기관·개인회원 무료
        The carbon capture and storage (CCS) technology from industrial flue-gas has been an important environmental issue in these days. However, membrane process has a number of breakthrough-point to commercialization in scale-up. In this work, process optimization for high purity and high CO2 recovery with lower the capture cost has been investigated. Lab-made membrane pilot process using real flue gas has been also set up to derive industrial factor.
        11.
        2016.11 구독 인증기관·개인회원 무료
        분리막 공정은 압력장치에 사용되는 전기 사용량이 많아 이를 줄이기 위한 다양한 공정 옵션이 연구되고 있다. 본 연구에서는 분리막 공정에서 막 모듈에 sweeping 기체를 permeate에 불어넣어 모듈의 구동력을 증가시키는 방법으로, 특별한 공정 장치 추가 없이도, 효율적인 CO2 분리가 되는 공정을 연구하였다. 분리막 공정은 주요 장치비용(분리막, 압축기 등)과 운영비용(전기, 스팀)을 평가 하였다. MATLABⓇ에서 분리막 모델을 개발하었으며, 분리막 공정에 가능한 모 든 구조들을 초구조로 경제성 평가 모델을 기준으로 평가되었다. 본 연구는 2014년도 정부(미래창조과학부)의 재원으로 (재)한국이산화탄소포집 및 처리연구개발센터의 지원을 받아 수행된 연구임(2014M1A8A1049305).
        12.
        2016.11 구독 인증기관·개인회원 무료
        Membrane is a relatively new industrial gas separation technology and has been studied as an alternative CO2 capture technologies to amine absorption. Membrane processes have a merit such as low energy use, small footprint, no by-products formation, and simple operating condition. When applied to flue gas CO2 capture, low CO2 concentration and normal pressure of flue gas stream places a practical limits on the membrane operation. The up-to-date membranes should allow module performance to rise to levels practical for fossil-fuel power station use. In this talk, membrane module is being evaluated for flue gas treatment. Membrane processes using several membranes, which are now being studied under the R&D projects granted by KCRC, are investigated to capture CO2 from the simulated gas.
        13.
        2015.11 구독 인증기관·개인회원 무료
        Mathematical models are developed for single and multi-stage membrane processes to simulate gas separation in MATLAB®. The single-stage membrane process simulations are validated through comparison with mixed-gas experimental results at different operating condition. Based on this validated single-stage process model, multi-stage membrane processes including 2 or 3 stages membranes with recycle streams are simulated. The resulting simulation outputs are shown to reproduce experiment results with reasonable accuracy. Hence, this process modeling framework can be utilized in future design and optimization studies.
        14.
        2015.11 구독 인증기관·개인회원 무료
        The carbon capture and storage (CCS) technology from industrial flue-gas is an important environmental issue these days. Membrane process can be competitive technology for its relatively small footprint and eco-friendly system. Many membrane modules with high selectivity and excellent flux have been developed so far. However, the high purity and recovery for CO2 capture can be achieved by optimization of operating conditions such as membrane area, feed/permeate pressure ratio and humidity of flue gas as well as membrane permeance or selectivity. In this study, we discuss the effect of operating parameters for high CO2 purity and recovery at permeate side. Using polymeric hollow fiber membrane, the single membrane process was tested to figure out the effect of feed flow rate, pressure ratio, membrane area and moisture content.
        15.
        2012.10 구독 인증기관·개인회원 무료
        Traumatic insemination (TI), an extraordinary copulation strategy, is most prevalent in cimicoid true bugs (Insecta: Hemiptera) among invertebrates including insects. Here, we resolved the evolutionary history of TI and the females’ adaptations by conducting molecular phylogenetic analyses and comparative studies based on the phylgenetic relationships. We found a sister group relationship of Curaliidae + Lasiochilidae, which are the only groups among Cimicoidea not likely engaged in TI. Divergence time estimates revealed that TI is a behavior of antiquity that first evolved in the Early Jurassic 188Mya (95% highest posterior density = 157 – 221). Furthermore, ancestral character state reconstructions indicated that TI evolved only once from standard insemination in Cimicoidea. The results revealed that only TI is correlated with PS among the biological traits, and that evolutionary acquisition of PS was driven by selection of TI. Additionally, we found that not only are the three types of PS homoplastic to each other, but also that each of types could not be a homologous feature despite of same terminology, which suggests convergent evolution of the females’ morphology have occurred as females were adapting to TI.
        16.
        2012.10 구독 인증기관·개인회원 무료
        Cimicomorpha is one of the most diverse groups in true bugs, and attract a great attention for a variety of reasons, among them, extraordinary insemination methods in the bed bugs and their relatives (Cimicoidea), feeding-habits alternations in the plant bugs (Miridae), parasitism in the bed bugs and their relatives (Cimicidae and Polyctenidae), agricultural pests in the lace bugs and the plant bugs (Tingidae and Miridae), biological control agents in the minute pirate bugs and the plant bugs (e.g., the genus Orius), disease transmission in the Triatominae (Reduviidae), and micro-habitat transition in the assassin bugs and the flower bugs (Reduviidae and Anthocoridae). In this talk, we propose the phylogenetic relationships within the Cimicomorpha especially including some critical taxa in terms of the biological traits such as haemocoelic insemination and parasitism (e.g., the species belonging to Lasiochilidae, Lyctocoridae, Prostemminae and Corydromius). Based on the phylogenetic results, we also present the evolutionary history of the specialized biological traits of the Cimicomorpha using phylogenetic comparative analyses.
        17.
        2011.05 구독 인증기관·개인회원 무료
        In a revision of four Eurydema speices recorded in Far East Asia, we confirm only two species, one of which consists of two subspecies: E. dominulus (Scopoli 1763) [=E. pulchra (Westwood 1837), syn. nov.], E. gebleri gebleri Kolenati 1846, and E. gebleri rugosa Motschulsky 1861 [stat. nov.]. In order to prove the above taxonomic changes, we compared three major characters; (1) the color patterns, (2) the mitochondrial COI (DNA barcoding) and (3) cross– breeding fertility (inter–specific copulation). Two subspecies, E. g. rugosa and E. g. gebleri, preserve their own unique coloration patterns, confirmed by the intra–subspecific copulation and breeding. Interestingly, the 1st progeny from the inter–subspecific copulation of E. g. rugosa♂ X E. g. gebleri♀ (or E. g. gebleri♂ X E. g. rugosa♀) take the coloration patterns inherited from E. g. gebleri.
        18.
        2010.10 구독 인증기관·개인회원 무료
        We present the first comprehensive cladistic analysis of Miridae, the plant bugs, based on analysis of 3935 base pairs of mitochondrial (16S, COI) and nuclear (18S, 28SD3) DNA for 91 taxa in seven subfamilies. We analyzed the data using maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) phylogenetic frameworks. A Bayesian relaxed molecular clock was used to examine divergence times, and ancestral feeding habits were reconstructed using parsimony and a Bayesian approach. Clades recovered in all analyses are as follows: Cimicomorpha, Miroidea, and Miridae; Bryocorinae: Bryocorini; Stenodemini; Mirinae; Deraeocorinae (Clevinemini + Deraeocorini); Cylapinae; Isometopinae; Bryocorinae: Dicyphini; Orthotylini; Phylinae (Phylini + Pilophorini), and Phylinae is sister-group to all the remaining mirid taxa. These results are largely congruent with former hypotheses based on morphological data with respect to the monophyly of various subfamilies and tribes however, our results indicate that the subfamily Bryocorinae is not a monophyletic group as the two tribes, Dicypini and Bryocorini, were separated in our phylogeny. Ancestral feeding state reconstructions based on Bayesian and parsimony inference were largely congruent and both reconstructed phytophagy at the root of the Miridae.
        19.
        2010.05 구독 인증기관·개인회원 무료
        Investigating the molecular clock, the ancestral character states, and the correlated evolution of discrete binary traits on phylogenetic trees, we studied the evolutionary history of the family Anthocoreidae, using ~3000bp of the mitochondrial 16S rRNA and nuclear 18S rRNA and 28S rRNA genes for 44 taxa. The BEAST and BayesTraits were used to examine the divergence times, cladogenesis, and historical habitat patterns. The correlated evolution of discrete characters was tested by reversible-jump Markov chain Monte Carlo. Our results suggest that (i) the ancestral habitat patterns of dead plants may have served as an important rule for the stem group of anthocorids; (ii) the radiation of angiosperms and the prey insect in the mid-Cretaceous might have provided anthocorids with more habitat options; and (iii) the transition of habitats played an important role for the change of ovipositor patterns in the family Anthocoreidae.
        20.
        2015.07 서비스 종료(열람 제한)
        Much effort has been expended to find agronomically important QTLs for improving soybean yield. However, the complexity of genome, such as genome duplication, limits the utility of genome-wide association studies and linkage analyses to identify genes controlling yield traits. We propose the variation block method, a three-step process for recombination block detection and comparison. The first step is to detect variations by comparing short-read DNA sequences of the cultivar to a reference genome of the target crop. Next, sequence blocks with variation patterns are examined and defined. The boundaries between the variation-containing sequence blocks are regarded as recombination sites. All the assumed recombination sites in the cultivar set are used to split the genomes, and the resulting sequence regions are named as variation blocks. The practicality of this approach was demonstrated by the identification of a putative locus determining soybean hilum color and known genes such as flower color gene. We suggest that the variation block method is an efficient genomics method for recombination block-level comparison of crop genomes. We expect that this method holds the prospect of developing crop genomics by bringing genomics technology to the field of crop breeding.
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