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        검색결과 313

        82.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper seeks to present a multi-control method that can contribute to effective control of the production line with multiple bottleneck processes. The multi-control method is the production system that complements shortcomings of CONWIP and DBR, and it is designed to determine the raw material input according to the WIP level of two bottleneck processes and WIP level of total process. The effectiveness of the production system developed by applying the multi-control method was verified by the following three procedures. Raw material input conditions of the multi-control method are as follows. First, raw materials are go into the production line when the number of the total process WIP is lower than established number of WIP in total process and first process is idle. Second, raw materials are introduced when the number of WIP of two bottleneck processes is lower than the established number of WIP of each bottleneck process. Third, raw materials are introduced when the first process and in front of bottleneck process are idle even if the number of WIP in the total process is less than established number of WIP of the total process. The production line with two bottleneck processes was selected as the condition for production environment, and the production process modeling of CONWIP, DBR and multi-control production method was defined according to the production condition. And the optimum limited WIP level suitable for each system was obtained by applying a genetic algorithm to determine the total limited number of WIP of CONWIP, the limited number of WIP of DBR bottleneck process, the number of WIP in the total process of multi-control method and the limited number of WIP of bottleneck process. The limited number of WIP of CONWIP, DBR and multi-control method obtained by the genetic algorithm were applied to ARENA modeling, which is simulation software, and a simulation was conducted to derive result values on the basis of three criteria such as production volume, lead time and number of goods in-progress.
        4,000원
        83.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As fashion and distribution companies have increasingly turned to implementing marketing activities that use omni-channel strategies, it is imperative to explore consumer-oriented evaluations of omni-channel shopping for fashion products. Through contributing to the growing research flow of consumer behavior within omni-channel contexts, the current study explores consumer motivations for omni-channel fashion shopping and their impacts on the decision-making stages of fashion products. The authors first performed in-depth interviews with six Korean consumers and confirmed the four types of consumer motivation for omni-channel shopping, and how decision- making processes react to fashion companies’ omni- channel marketing strategies. These findings were used to set survey items for the main study. Based on the results and findings of previous literature, an online survey was conducted with 300 participants who had actual experience with omni-channel shopping for fashion products. The statistic results from the survey revealed the following: First, the in-depth interviews allowed the authors to confirm four factors of omni-channel shopping motivation (ubiquity, efficiency, convenience, and impulsiveness). Second, the survey showed the authors that among the four factors of omni-channel shopping orientation, impulsiveness had the greatest effect on consumer behaviors at the preand on-purchase stages, while the ubiquity factor had the greatest effect at the post-purchase stage. As such, the study empirically tested the omni-channel-specific factors of shopping orientation and motivation. In addition, it showed the effect of omni-channel marketing on various stages of the decision- making process and the study’s limitations and implications were discussed.
        4,900원
        84.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 막결합생물반응조(MBR)공법을 비롯한 하수고도처리공법에서 유입하수량의 변화에 따른 슬러지 특성 변화를 파악하고자 하였다. 일 1.5톤을 처리하는 모형실험시설에서 설계유량 대비 유입하수량을 100, 70, 40, 10%로 변 화시켜가며 이에 따른 비탈질속도(specific denitrification rate)와 비질산화속도(specific ammonia oxidation rate)의 변화를 측 정하였다. 각 공법의 폭기조에서 채취한 슬러지의 비질산화속도는 유입하수량 100% 조건에서 세 가지 공법 모두 유사한 값 (0.10 gNH4/gMLVSS/day)으로 측정되었다. 유입하수량이 70%에서 40%로 감소함에 따라 비질산화속도가 크게 감소하는 경향을 나타냈다. 비탈질속도 역시 유입하수량이 감소함에 따라 최대 50%가량 감소하였다. 유입하수량이 감소할수록 비탈질속 도와 비질산화속도가 감소하는 경향을 나타냈으나 원수의 총질소 농도와 반응조 내 미생물 농도를 고려하면 질소제거율에 영향을 미칠 정도는 아니었다. 따라서 유입하수량이 감소하는 경우에도 반응조 내 미생물 농도를 높게 유지할 수 있다면 안정적인 질소 제거가 가능할 것으로 판단된다.
        4,000원
        85.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The influence of task complexity on second language (L2) writing performance has been researched near-exclusively in relation to the linguistic complexity of the learners’ written products, while only limited attention has been paid to the online writing processes. In order to fill this gap, the present study focused on the effects of task demands on writing processes as reflected in keystrokes. Forty-four L1 Korean speakers were randomly assigned to either simple or complex condition, and asked to write an argumentative essay. For the simple condition, content support was provided, whereas no such additional information was provided for the complex condition. During the writing task, participants’ entire keystroke loggings were recorded, and analyzed in terms of fluency, pausing, and revision behaviors. The lexical and syntactic complexity of the written products was also analyzed and compared between the two task conditions. The results indicated that greater task demands significantly increased the number of pauses and revisions, having negative influence on fluency. Also, lexical rarity and phrasal complexity decreased under the complex condition. The results are discussed with respect to fuller understanding of the task-based approach to L2 writing.
        5,800원
        86.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the major sources causing eutrophication and algal blooms of lakes or streams is phosphorus which comes from point and nonpoint pollution sources. HAP (hydroxyapatite) crystallization using granular alkaline materials can achieve the decrease of phosphorus load from wastewater treatment plants and nonpoint pollution control facilities. In order to induce HAP crystal formation, continuous supply of calcium and hydroxyl ions is required. In this research, considering HAP crystallization, several types of lime-based granular alkaline materials were prepared, and the elution characteristics of calcium and hydroxyl ions of each were analyzed. Also, column tests were performed to verify phosphorus removal efficiencies of granular alkaline materials. Material_1 (gypsum+cement mixed material) achieved the highest pH values in the column tests consistently, also, Material_2 (gypsum+slag mixed material) and Material_3 (calcined limestone material) achieved over pH 9.0 for 240 hours (10 days) and proved the efficiencies of long-term ion supplier for HAP crystallization. In the column tests using Material_3, considerable pH increase and phosphorus removal were carried out according to each linear velocity and filtration depth. T-P removal efficiencies were 87.0, 84.0, 68.0% and those of PO4-P 100.0, 97.0, 80.0% for linear velocity of 1.0, 2.5, 5.0 m/hr respectively. Based on the column test results, the applicability of phosphorus removal processes for small-scale wastewater treatment plants and nonpoint pollution control facilities was found out.
        4,000원
        87.
        2017.11 KCI 등재 구독 인증기관·개인회원 무료
        This paper discusses enactment and enforcing processes of the Japanese renewables Feed in Tariff (FIT) Law and its amendment of 2017. Thanks to the introduction FIT in 2012, the installed capacity of renewable energy is growing rapidly. As of 2015, the renewable electricity ratio in the generated electric power amount of Japan is 14.6 percent. Meanwhile, the levy burden (surcharge) reached JPY 2.1 trillion (aprx. USD18.7 billion). Through the enactment process of the FIT Law, the upper limit of the burden initially determined by the Japanese Diet was removed. A fundamental measure could not be taken to control the installation and the burden since the law does not allow for revisions on the system based on the results of renewable installation, even if the financial burden increases rapidly. Therefore, the Japanese Diet weakened the efficiency of the FIT Law in Japan.
        88.
        2017.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the present study the microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes was characterized and identified based on various microstructure analysis methods including optical and scanning electron microscopy, and electron backscatter diffraction(EBSD). Although low-carbon steels are usually composed of α-ferrite and cementite(Fe3C) phases, they can have complex microstructures consisting of ferrites with different size, morphology, and dislocation density, and secondary phases dependent on rolling and accelerated cooling conditions. The microstructure of lowcarbon steels investigated in this study was basically classified into polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite based on the inverse pole figure, image quality, grain boundary, kernel average misorientation(KAM), and grain orientation spread(GOS) maps, obtained from EBSD analysis. From these results, it can be said that the EBSD analysis provides a valuable tool to identify and quantify the complex microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes.
        4,000원
        89.
        2017.11 구독 인증기관·개인회원 무료
        전기⋅전자산업이 급격하게 발전함에 따라 유가금속 및 희소금속의 수요가 급증하고 있다. 유가금속들은 주로 제련산업 공정에서 다량 방출되며, 회수기술 부족으로 중화, 치환, 흡착을 통해 폐기되어 큰 비용으로 경제적이지 못하다. 이에 분리막을 통한 유가금속회수 소재개발의 필요성이 강조되고 있다. 유가금속이 포함된 습식제련 공정 침출액(15% 황산 용액, 온도 60°C)은 다량의 다가이온과 1가이온을 포함하고 있기 때문에 이온별 분리가 가능해야 하며, 특히 구리와 같은 2가 유가금속 분리성능이 우수해야 한다. 또한, 지속적인 분리/농축을 위해 산에 대한 안정성이 중요하다. 따라서 본 연구를 통해 2가 금속 배제율 98%, 유량 33GFD 성능을 1개월 이상 유지하는 나노분리막 제조 연구 개발을 수행하고 있다.
        90.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 역전기투석 공정에서 발생 가능한 막오염 현상을 in-situ로 측정하기 위하여 임피던스 스펙트로스 코피 방법을 도입하여 실제 발생한 막오염 현상 측정 방법을 제시하였다. 얻어진 임피던스 데이터를 활용하여 Nyquist 도시 법과 어드미턴스 도시법으로 스펙트럼을 도시하였으며 두 도시법 모두 유의미한 막오염 현상을 감지할 수 있었다. 또한 초기 막오염 현상에서 음이온 교환막 표면에 막오염물의 불안정한 축적 현상 및 역전기투석 공정의 운전 시간에 따른 막오염층의 구조적 변화를 감지할 수 있었다.
        4,000원
        91.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라에서는 다랑어 선망어업의 기술 경쟁력을 높이기 위한 많은 연구개발이 이루어지고 있으며, 이러한 노력으로 인하여 다랑어 선망어선의 선형개선과 어군 탐지를 위한 레이다, 소나 및 위성정보시스템의 개발로 인해 조업 효율이 향상되었다. 그러나 다랑어 선망어선에 탑재되는 보조 작업선인 스키프보트, 네트보트 및 스피드보트의 경우에는 본선의 기술 현대화에 비해 기술력이 낙후되어 있 는 실정이다. 이에 본 논문에서는 그물을 끌기 위한 양망의 기능과 프로펠러로부터 다랑어를 보호하기 위하여 설치된 철망을 가진 기존 의 네트보트의 선체를 워터제트 추진기 탑재가 가능한 선체로 변경하여 다랑어 보호, 선체저항 감소 및 운항성능 향상하고자 하였다. 결 과적으로 워터제트 형태에 적합한 선형에 대해 해양수산부 고시에 의거한 알루미늄 구조강도 기준을 적용한 시제선 제작하였으며 낙하 시험을 수행하여 안전성을 확인하였다. 또한 해상시운전을 통하여 기존의 네트보트는 2,500 RPM에서 속도는 12.0 knot, 예인력은 2,545 kgf 이며, 워터제트가 탑재된 네트보트는 3,200 RPM에서 속도는 26.7 knot, 예인력은 2,011 kgf로 워터제트가 탑재된 네트보트 또한 다랑어 선망 어선의 보조 작업선으로 예인용량 기준에 충분히 만족함을 알 수 있었다.
        4,000원
        92.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although Semisulcospira libertina is generally regarded as a supplement for the alleviation of alcohol hangover, little is known about its effects on cell metabolism. Therefore, this study was conducted to analyze the constituents of the extracts prepared using different extraction methods and to compare their biochemical properties. The amino acid contents were found to be much higher in acidic and enzymatic hydrolysates than hot water extracts from S. libertina. DPPH radical scavenging activities in acidic and enzymatic hydrolysates were higher than those of hot water extracts. Three types of S. libertina hydrolysate was added to HepG2 cells damaged by acetaminophen (AAP), after which the survival rate of HepG2 cell were measured. In addition, lactate dehydrogenase (LDH) activities in the culture media were evaluated. The survival rates of HepG2 cells were 77.0±4.3% and 81.5±1.3% at 3 h and 5h enzymatic hydrolysates, respectively. These cell survival rates were higher compared to those of the negative control group (67.8±4.3%) treated only with acetaminophen. Cellular toxicities induced by treatment with AAP were also significantly alleviated in response to treatment with the extracts of S. libertina. In addition, the activities of 2 key enzymes that metabolize ethanol, alcohol dehydrogenase and aldehyde dehydrogenase, were upregulated by 4.7- and 2.7-fold respectively in response to treatment with a 3 h enzymatic hydrolysate of S. libertina. Taken together, these results provide biochemical evidence of the method by which S. libertina exerts its biological functions, including the alleviation of alcohol hangover and the protection of liver cells against toxic insults.
        4,000원
        93.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although Semisulcospira libertina is generally regarded as a supplement for the alleviation of alcohol hangover, little is known about its effects on cell metabolism. Therefore, this study was conducted to analyze the constituents of the extracts prepared using different extraction methods and to compare their biochemical properties. The amino acid contents were found to be much higher in acidic and enzymatic hydrolysates than hot water extracts from S. libertina. DPPH radical scavenging activities in acidic and enzymatic hydrolysates were higher than those of hot water extracts. Three types of S. libertina hydrolysate was added to HepG2 cells damaged by acetaminophen (AAP), after which the survival rate of HepG2 cell were measured. In addition, lactate dehydrogenase (LDH) activities in the culture media were evaluated. The survival rates of HepG2 cells were 77.0±4.3% and 81.5±1.3% at 3 h and 5h enzymatic hydrolysates, respectively. These cell survival rates were higher compared to those of the negative control group (67.8±4.3%) treated only with acetaminophen. Cellular toxicities induced by treatment with AAP were also significantly alleviated in response to treatment with the extracts of S. libertina. In addition, the activities of 2 key enzymes that metabolize ethanol, alcohol dehydrogenase and aldehyde dehydrogenase, were upregulated by 4.7- and 2.7-fold respectively in response to treatment with a 3 h enzymatic hydrolysate of S. libertina. Taken together, these results provide biochemical evidence of the method by which S. libertina exerts its biological functions, including the alleviation of alcohol hangover and the protection of liver cells against toxic insults.
        4,000원
        95.
        2017.04 구독 인증기관·개인회원 무료
        Ochratoxin A, which is frequently detected in cereals and infant diets worldwidely, is a mycotoxin to damage mainly the kidney and liver. Because ochratoxin A is highly thermostable compound. it is necessary to study ways of reducing level of ochratoxin A by controling processing steps. However, food processes, including extrusion, expansion, roasting, and steam cooking, which are used in order to mitigate the contents of ochratoxin A, are known to produce polycyclic aromatic hydrocarbons, which are generated from radicals decomposed by pyrolysis. Therefore, this study analyzed the levels of 4 polycyclic aromatic hydrocarbons, benz (a) anthracene, chrysene, benzo (b) fluoranthene and benzo (a) pyrene in rice-based products made in high pressure and heating process. Rice samples were finely ground, and homogenized samples were alkaline treatement with 1 M KOH/EtOH and extracted with liquid-liquid extraction method using n-hexane. The extracted solution was pretreated with a silica cartridge. The purified solution was dried with nitrogen gas and dissolved in 1 mL of dichloromethane and injected into GC/MSD. We had overall recoveries for 4 polycyclic aromatic hydrocarbons spiked into rice samples ranging from 92.8 to 110.2%. The limit of quantitations of benz (a) anthracene, chrysene, benzo (b) fluoranthene and benzo (a) pyrene in rice-based product were 0.19 ng/g, 0.38 ng/g, 0.51 ng/g, and 0.31 ng/g, respectively. However, these 4 polycyclic aromatic hydrocarbons in all processed rice samples were not detected.
        98.
        2016.11 구독 인증기관·개인회원 무료
        본 연구에서는 SWRO공정의 Feed Dilution에 따른 SWRO Permeate Flow의 민감도 분석 및 Hybrid Module Design을 통한 개선방안을 검토하였다.
        99.
        2016.09 구독 인증기관 무료, 개인회원 유료
        Can awakening to planetary consciousness open pathways to personal and social healing, reconciliation and redemption in the aftermath of mass suffering like Jeju 4.3? In this article, I aim (a) to identify the characteristics of planetary consciousness using my observations on a peace pilgrimage and case examples from Jeju, and (b) to clarify how planetary consciousness is developed through transformative learning processes. Planetary consciousness is the awareness that all beings, energies and phenomena are profoundly interconnected and interdependent. The development toward planetary consciousness can be understood using models such as the Transformative Learning Process, the Radical Forgiveness Method, and the Social Healing Through Justice Model. Progressing through the stages results in openness to multidimensional thinking and knowing. Individuals and communities who have worked through transformative learning processes demonstrate the possibility of genuine healing, reconciliation and the restoration of justice and dignity. Keywords
        5,400원
        100.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effectiveness of electrodialysis in removing inorganic arsenic from groundwater was investigated. To evaluate the feasibility of the electrodialysis, operating parameters such as treatment time, feed concentration, applied voltage and superficial velocity were experimentally investigated on arsenic removal. The higher conductivity removal and arsenic removal efficiency were obtained by increasing applied voltages and operation time. An increase of salinity concentrations in arsenic polluted groundwater exerted no effects on the arsenic separation ratios. Arsenic polluted waters were successfully treated with stack voltages of 1.8 ~ 2.4 V/cell-pair to approximately 93.4% of arsenic removal. Increase flow rate in diluate cell gave positive effect to removal rate. However, increase of superficial velocity in the concentrated cell exerted no effects on either the conductivity reduction or on the separation efficiency. Hopefully, this paper will provide direction in selecting appropriate operating conditions of electrodialysis for arsenic removal.
        4,000원
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