Bioinspired Cellulose Nanocomposites and Mechanical Properties

문성민,허경아,심봉섭 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

The brick and mortar structure of nacre has shown remarkable mechanical properties in nature. Inspired by their hierarchically aligned structures between chitin fibers and calcium carbonate platelets, we have fabricated nacre-like nanolayered structures of cellulose nano-fiber (CNF) and montmorillonite (MMT) via vacuum filtration techniques with different CNF/MMT ratio. The molecular structures of CNF-MMT films were observed by scanning electron microscopic and X-ray diffraction. The mechanical strength and modulus of CNF-MMT nano-composite were higher than those of pure CNF and MMT films. Furthermore, the CNF-MMT films have shown fire-retardant properties while containing large amounts of cellulose. Thus, CNF-MMT nanocomposite can be a good candidate for environmental-friendly materials in the wide ranges of industrial application fields.

구매력평가이론에 근거한 북한 가격 및 환율 분석

문성민 통일연구원 2008 統一 政策 硏究 Vol.17 No.2

본 연구에서는 「일물일가의 법칙(Law of one Price; LOP)」과 「구매력평가(Purchasing Power Parity; PPP) 이론」에 근거하여 이원화된 북한의 가격과 환율의 특성을 분석하였다. 2002년 7.1조치 이후 북한의 ‘국정가격 및 국정환율’과 ‘시장가격 및 시장환율’에 대한 입수 가능한 시계열 자료를 이용하여 북한과 주변국(중국 등)의 쌀 가격에 대한 LOP 성립여부를 검정하였으며 PPP 이론에 근거하여 북한 환율의 고평가여부를 분석하였다. 분석결과 북한의 ‘국정가격 및 국정환율’은 LOP가 성립하지 않으며 PPP 이론에 근거해 계산된 균형환율로 회귀하지도 않는 것으로 분석되었다. 이에 반해 ‘시장가격 및 시장환율’은 비록 가격 자료가 쌀에 국한되어 있다는 자료상의 제약이 있으나 LOP가 성립하는 것으로 나타났으며 환율도 PPP 이론에 근거한 균형환율로 회귀하려는 특성을 가지고 있는 것으로 분석되었다. 이는 북한의 ‘국정가격 및 국정환율’이 북한경제나 국제시장 상황을 제대로 반영하지 못하는 반면 ‘시장가격과 시장환율’은 이를 일정 정도 반영하고 있기 때문인 것으로 보인다. 따라서 북한경제 상황을 정확히 분석하려면 ‘시장가격 및 시장환율’을 이용하는 것이 바람직할 것으로 보인다. The purpose of this paper is to empirically analyze the characteristics of North Korean prices and exchange rates by employing the law of one price (LOP) and the purchasing power parity (PPP) theory. This paper tests whether the LOP holds for rice prices in North Korea and its neighboring countries (China etc), and examines whether North Korean exchange rates are overestimated by using the PPP theory. For the analysis, I use the time series data on ‘official prices and exchange rates’ and ‘market prices and exchange rates’ in North Korea after the‘7.1 Measures (July, 2002).’ According to the analysis, the LOP does not hold for North Korean ‘official rice prices,’ and ‘official exchange rates’ do not have tendencies to revert to the equilibrium exchange rates which are calculated based on the PPP theory. In contrast, the LOP holds for North Korean ‘market prices’ when tested for rice prices. In addition, ‘market exchange rates’ have tendencies to revert to the equilibrium exchange rates calculated on the basis of the PPP theory. These findings illustrate that North Korean ‘official prices and exchange rates’ seem not to reflect North Korean economy and the international market condition sufficiently, whereas North Korean ‘market prices and exchange rates’ do so to a certain extent. In this regard, for the more accurate analysis on the North Korean economy, it may be desirable to use North Korean ‘market prices and exchange rates’ rather than ‘official prices and exchange rates.’

전기탈이온 정수기술

문성민,강상현 한국막학회 2019 한국막학회 총회 및 학술발표회 Vol.2019 No.11

작업시간과 육체적인 작업부하를 고려한 혼합모델 조립공정의 라인밸런싱

문성민,권근섭,최경현 대한산업공학회 2004 산업공학 Vol.17 No.3

수요 특성이 계층적 수요예측법의 퍼포먼스에 미치는 영향:해군 수리부속 사례 연구

문성민 한국경영과학회 2012 經營 科學 Vol.29 No.1

The demand for naval spare parts is intermittent and erratic. This feature, referred to as non-normal demand, makes forecasting difficult. Hierarchical forecasting using an aggregated time series can be more reliable to predict non-normal demand than direct forecasting. In practice the performance of hierarchical forecasting is not always superior to direct forecasting. The relative performance of the alternative forecasting methods depends on the demand features. This paper analyses the influence of the demand features on the performance of the alternative forecasting methods that use hierarchical and direct forecasting. Among various demand features variability, kurtosis, skewness and equipment groups are shown to significantly influence on the performance of the alternative forecasting methods.

한국어 발음 변환기(G2P)의 현황과 성능 향상에 대한 언어학적 제안

문성민,김수한,고언숙 한국언어정보학회 2022 언어와 정보 Vol.26 No.2

Grapheme-To-Phoneme (G2P) converts an input letter sequence into its corresponding pronunciation. Several rule-based G2P models are available for Korean, but their performance in view of individual phonological rules in Korean is not well-investigated. We establish phonological rules to be reflected in a G2P model for Korean, and test the model performance of two most popular G2P models of Korean, i.e., g2pk and KoG2P, regarding their performance on each of these rules. We created a golden corpus to evaluate the performance of the current G2P models based on manual phonetic transcription. We then measured the performance of two G2P models, and identified the phonological rules in which the models show relative success or failure in deriving the correct output. We implemented additional phonological rules such as h-deletion, ui-variation, consonant place assimilation, and restructured the ordering of rules such as h/th-neutralization in the model. We show that our revised model makes a substantial improvement on model performance. Further, we argue that the major limitation of the current rule-based approaches to G2P is in its binary approach to phonological rules and lack of information about prosodic boundaries. We propose that a rule-based G2P system should reflect the stochastic nature of phonological processes informed by existing research on the gradient nature of phonological rule application as a function of factors such as lexical frequency and speech register.

전기탈이온 기술의 정수기 응용

문성민,이수영,강상현 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

축전식탈염기술(capacitive deionization, CDI)은 높은 에너지 효율과 회수율의 장점을 가지고 있어 새로운 탈염 기술로 큰 관심을 받고 있다. CDI 기술은 전극성능 향상, 운전 시스템 최적화, 대용량 상업화 연구가 활발히 진행되어 왔으나 가정용 제품에 적용된 사례는 매우 드물다. 본 발표에서는 CDI 기술을 적용한 정수기 개발에 있어 요구되는 요소 기술과 해결해야 할 과제에 대해서 선행 연구 내용을 기초로 논하고자 한다.

연구논문 : 조우규범과 개인 공간 유지성향이 혼잡지각에 미치는 영향 : 청계천 방문객을 대상으로

문성민,문귀남 대한관광경영학회 2007 觀光硏究 Vol.22 No.3

본 연구는 청계천 산책로의 평균 너비는 1.5~2m로 협소한 반면 평균 300m간격으로 설치된 진출입로는 접근성을 향상시켜 공간적 밀도를 증가시키고, 산책로 이용객의 보행행태는 사회적 밀도를 증가시켜 혼잡이 지각될 것으로 가정하였다. 비록 혼잡이 지각된다 하더라도 청계천은 공유해야 할 공공재라는 사회적 인식과 무료입장으로 인한 대응행동은 다른 방문객들로부터 일정거리를 유지하고자 하는 개인 공간 개념으로 접근하였다. 밀도와 혼잡, 그리고 개인 공간에 대한 선행연구를 검토한 후 3개 연구 과제를 제시하였고 측정변수는 연구자와 전문가의 토의를 거쳐 탐색적으로 개발·적용되었다. 일반적 보행흐름의 역방향으로부터 접근해 오는 방문객과의 조우상황에서 혼잡지각은 부정적이었으며 여성의 혼잡지각은 역방향 조우유형에서 보다 부정적이었다. 여성은 후방으로부터 접근해 오는 다른 방문객으로부터 일정거리를 유지하기 위해 발걸음을 재촉하는 개인 공간 유지행동이 남성보다 높게 나타났다. Most research on perceived crowding has focused exclusively on "backcountry" situations, i.e., outdoor recreation areas such as national parks, wilderness, rivers, lakes, etc. In addition, relevant theories on perceived crowding have been limited to either social carrying capacity or norm. Therefore, no new theory adequate for perceived crowding in "frontcountry" areas has been proposed yet. The aim of this study is to investigate how both encounter norm and personal space influence perceived crowding of visitors in Cheonggyecheon. The literature review on density and crowding in the tourism and leisure d\discipline and about proxemics and personal space in anthropology and psychology was carried out. Based on the literature review, three research questions were proposed, and tentative measurement scales were developed. The validity and reliability of the scale for encounter norm were confirmed by an exploratory factor analysis, which considered the factor of "perceived crowding in cross-encounters". To female respondents, perceived crowding was perceived as very negative when approached by on-coming visitors from the opposite direction. In addition, female respondents felt the need to distance themselves from other visitors approaching from behind. This exploratory study extends crowding-related research usually limited to the area of cultural anthropology, which is rarely used in studies of tourism,.into tourism/leisure discipline.

전라남도 중소기업 경영안정자금 영향 분석

문성민,조영석,이상호 한국창업학회 2018 한국창업학회 Conferences Vol.2018 No.4

Binary system for hierarchically aligned structure of CNF/Clay nanocomposites and mechanical properties

문성민,허경아,심봉섭 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Bioinspired binary system of cellulose nanofiber (CNF) and montmorillonite (MMT) has shown the hierarchically aligned structure. Their brick and mortar structures show remarkable mechanical properties. Binary system nanocomposites film of CNF and MMT were observed by X-ray diffraction and scanning electron microscopic for crystallinity calculation and hierarchically aligned structure images with different CNF/MMT ratio. CNF and MMT nanocomposites have shown higher mechanical modulus and tensile strength than those of pure CNF and MMT films. Furthermore, Optical transparency of films has been compared with different MMT and fire retardancy and flexibility have been observed. CNF and MMT nanocomposites show the potential to be good candidate for environmentally friendly materials in various fields.