이서구시 암각서

이서구,이서구(추정) 전북역사문화학회 2007 전라북도금석문대계 Vol.1 No.-

Structured and Property-Based Examination of Lignin-Incorporated Thermoplastic Polyurethane Composites

이서구,이희은,양기준,Mandeep Poonia,김광호,Chang Geun Yoo,위정재 한국고분자학회 2024 한국고분자학회 학술대회 연구논문 초록집 Vol.49 No.1

어촌 캠핑객의 특성에 따른 만족 영향요인 분석

이서구,강동선 한국해양비즈니스학회 2022 해양비즈니스 Vol.- No.52

The purpose of this study is to suggest a way to revitalize fishing village camping by analyzing and presenting the factors that influence the personal background characteristics of fishing village campers on fishing village camping satisfaction. The analysis method used binary logistic regression analysis. The dependent variable was satisfaction with fishing village camping, and the independent variable consisted of 24 groups of general characteristics, camping experience, campsite selection attributes, and campsite activity preference. As a result of the analysis, it was found that 6 variables of fishing village campers' age, residence, monthly income, camping schedule, number of camping, and camping experience had an effect on their satisfaction with fishing village camping. Through this study, implications such as ways to secure loyal customers for fishing village camping, creation of a camping site that can satisfy camping motives, and the need for convenient facilities and safety/sanitation management were derived.

베이지안 추정을 이용한 국내 자동차 시장의 다항 프로빗 모형 분석

이서구 한국상품학회 2016 商品學硏究 Vol.34 No.5

The main purpose of this study is to explore factors that may have effect on consumers' purchase decision for Korean automotive market using the multinomial probit model (MNP) based on Bayesian estimation. Although the MNP is one of excellent alternatives of the multinomial logit model because of the relaxation of the independence of irrelevant alternatives assumption, it is seldomly used due to computational difficulties for estimation. But some recent researches showed that the estimation of the MNP can be resolved by using Bayesian estimation with Gibbs sampling. This study tries to find meaningful variables those can explain three kinds of consumer's purchase decision for Korean automotive market, such as mid-size sedan brand selection, sedan segment selection, and car type (sedan/SUV) selection. The independent variables those are selected based on literature review are classified into two categories, the individual characteristics and the product attributes. The individual characteristics are gender, age, household income, weights of product attributes, and attitude toward manufacturers, and the product attributes are price, fuel expense, mileage, and fuel efficiency. The result of the brand selection model analysis showed that price, weights of product attributes, and attitude toward manufacturers have an effect on the selection of almost all brands, and that age has an effect on the selection of only one brand. The result of the second study showed that age, price, fuel efficiency, weights of product attributes, and attitude toward manufacturers have significant effect on a consumer's car segment selection. And household income, price, price/income ratio, and attitude toward manufacturers effect on a consumer's automotive type selection such as sedan and SUV. The results of this study suggests that the MNP which is seldomly used can be applied to explain a consumer's choice. And also, as results of analyzing domestic market are usually different from those of analyzing foreign markets, variables those are proved to be significant can be used as valuable input for future research such as market structure analysis. 본 연구는 해외 자동차 시장 대비 상대적으로 연구가 미흡한 국내 자동차 시장에서 소비자 의사결정에 영향을 미치는 요인들을 탐색하고자 한다. 또한 분석능력이 우수하고 현실적인 가정이지만 모수 추정이 어려워 잘 사용되지 않았던 다항 프로빗 모형을 이용하여 특히, 소비자의 여러 선택상황들을 설명하고자 한다. 세부적 연구 목적은 다음과 같다. 첫째, 자동차 구매 시 발생 가능한 세 가지 계층별 선택상황 즉, 상표, 차급, 그리고 차종 선택에 대해 영향을 미치는 개인과 제품 특성들을 국내 자동차 시장을 대상으로 탐색적으로 분석하고자 한다. 둘째, 베이지안 추정에 의한 다항 프로빗 모형을 이용하여 소비자의 선택에 영향을 미치는 주요 속성들을 규명하고 이를 향후 국내 자동차 시장구조 분석에 활용하고자 한다. 세 가지 선택 모형에 대한 설명변수로 기존 연구들을 참조하여 성별, 연령, 가구 소득, 소득 대비 가격비중, 구입 시 고려하는 속성 중요도, 그리고 제조회사에 대한 태도 등의 개인 특성과 구입가격, 연료비, 주행거리, 연비 등의 제품 속성을 투입하였다. 첫 번째 상표선택 모형의 분석 결과 개인 특성으로는 연령이 특정 상표 선택에 영향을 미치는 것 외에 구입가격, 속성 중요도, 그리고 제조회사에 대한 태도 등이 상표 선택에 영향을 주는 것으로 나타났다. 또한 깁스 샘플링을 이용한 추정 역시 신뢰할 수 있는 것으로 나타났다. 두 번째 연구 결과 연령, 구입가격, 연비, 속성 중요도, 그리고 제조회사에 대한 태도 등이 소비자의 차급 선택에 영향을 미치는 것으로 나타났다. 그리고 마지막으로 국내 자동차 시장을 차종에 따라 세단과 SUV로 구분하여 분석한 결과 선택에 영향을 미치는 유의한 요인은 가구소득, 구입가격, 소득대비 가격비중, 제조회사에 대한 태도 등으로 나타났다. 본 연구의 시사점은 다음과 같다. 첫째, 유용하지만 잘 사용되지 않던 다항 프로빗 모형을 이용하여 소비자 선택을 설명하였다. 둘째, 본 연구는 연령, 소득, 소득대비 가격비중, 속성 중요도, 제조회사에 대한 태도 등의 개인특성과 구입가격, 기름값, 주행거리, 실제 연비 등의 제품 속성을 사용하여 소비자의 다양한 선택 상황에 영향을 미치는 변수들을 규명하고자 하였다. 셋째, 국내 자동차 시장에서 유의하게 나타난 개인 및 제품 특성은 해외 자동차 시장의 분석 결과와 다를 수 있으므로 본 연구에서 규명된 변수들은 향후 국내 자동차 시장에 대한 연구에 유용하게 사용될 수 있을 것이다.

다양성 회피와 일차과정을 이용한 시장구조분석의 타당성 검증에 관한 연구

이서구,김준환 대한경영학회 2005 大韓經營學會誌 Vol.18 No.2

The purpose of this study is to build market structure analysis model at aggregate level using confirmatory approach under the assumption of variety avoiding having beta-binomial distribution, and to test the model's validity using brand switching data used in previous research.We estimated parameters using actual brand switching data and calculated likelihood chi-square statistic(goodness-of-fit) to verify five hypothetical market structures used in previous research. We found two significant hypothetical market structures, and introduced another goodness-of-fit statistic, modified AIC, to decide which market structure is better. And we got optimal market structure which has only one attribute, calorie, to explain actual non-alcholic beverages market structure.Our model is better than that of previous research which showed same result for us, because we used more parsimonious parameters. While we derived brand choice model using attribute-base in consumer information processing theory, the previous research derived their model using brand-base in utility maximization theory. Hence attribute-based choice model can explain brand choice activity and brand switching in the competitive marketplace better than brand-based choice model. In addition, first-order process assumption reflects more realistic environment than zero-order process assumption, because zero-order process assumption needs large number of parameters to explain brand switching at sub-category level in market structure. 본 논문에서는 상대적인 소비자 이질성을 고려한 다양성 회피 정도를 측정하는 과정에서 총체적 수준에서 시장구조를 분석하고자 하였다. 검증방법에서 소비자의 다양성 회피 정도는 베타분포를 갖는 것으로 가정하였다.박세훈의 기존 연구에서 제시한 동일한 자료를 이용하여 박세훈(1992)이 제시한 모델과 Kumar & Sashi의 모델과 본 연구 모형과 비교하는 방법으로 모형의 타당성을 검증하고자 하였다. 그 결과, 기존 연구들과 매우 유사한 결과를 얻을 수 있었다. 특히, 동일한 자료를 이용하여 분석한 Kumar & Sashi의 연구와는 일치된 결과를 보여 본 논문에서 사용한 모델의 이론적 타당성을 검증할 수 있었다. 이와 더불어, 상대적으로 적은 모수로서 유사한 결과를 보였음은 일차선택과정하에서의 다양성 회피행동에 기초한 시장구조분석 모델이 영차선택과정에 의한 시장구조분석 모델보다 더욱 간결한 모델이 될 수 있는 가능성을 보여준 것이라 할 수 있다.

Transmembrane Signal Transduction and Phosphoinositide-Generated Second Messengers

이서구 한국생화학분자생물학회 1988 생화학분자생물학회 소식 Vol.8 No.4

Phase-Separation Strategy for Synthesis of Extremely Negative Triboelectric Polymeric Sulfur Blends

이서구,윤혁준,최진혁,이종혁,장혜운,전지수,원수경,김아영,육지호,이민백,위정재 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Since the introduction of triboelectric nanogenerators (TENG), halogenated carbon-based polymers have widely been chosen as one of the most negative triboelectric materials due to the high electron affinity property of halogen atoms. Herein, we report a facile synthesis of extremely negative triboelectric polymers by blending fluorine-rich poly(2,3,4,5,6-pentafluorostyrene) (PPFS) along with polymeric sulfur, which can exceed triboelectric performance of conventional halogenated carbon-based polymers. PPFS is added in-situ during the inverse vulcanization of elemental sulfur along with 1,3-diisopropenylbenzene (DIB) crosslinker. Ground polymer blends were hot-pressed into films, which result in a phase separation of PPFS from sulfur copolymers to the hydrophobic air-interface. The surface localized PPFS molecules resulted in a long-term stable 8-fold and 9-fold increase in triboelectric voltages and currents, respectively, in comparison with commercial PTFE.

Modified Physical Properties of Polymer Composites Substitution of Hydroxyl Groups in Microcrystalline Cellulose Filler

이서구,조웅비,장새봄,유아란,위정재 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

Microcrystalline cellulose (MCC) has various advantages including high mechanical properties. However, too strong interactions among MCCs can lead to aggregation of the MCC fillers within polymer composites, which can reduce interfacial between polymer matrix and filler and reinforcement effects. Herein, we employed three different chemically modified MCC (m-MCC) where hydroxyl groups of the MCCs was substituted by either methyl or hydroxypropyl groups. The m-MCC and ester type thermoplastic polyurethane (TPU) were compounded by an extrusion process. As the chemical substitution of hydroxyl groups can reduce the number of hydrogen bonding sites or increase m-MCC intermolecular distances, both crystallinity of m-MCCs and polymer-filler interaction can also be manipulated. In this presentation, we will discuss structure-property relationships of TPU-MCC composites with focuses on correlation of crystallinity and dispersion of m-MCC with mechanical properties of the TPU-MCC composites.

고려상표군을 이용한 내구재 시장구조 분석에 관한 연구:자동차 시장에 대한 탐색적 분석방법

이서구 한국마케팅학회 2012 ASIA MARKETING JOURNAL Vol.14 No.2

Brand switching data frequently used in market structure analysis is adequate to analyze non- durable goods, because it can capture competition between specific two brands. But brand switching data sometimes can not be used to analyze goods like automobiles having long term duration because one of main assumptions that consumer preference toward brand attributes is not changed against time can be violated. Therefore a new type of data which can precisely capture competition among durable goods is needed. Another problem of using brand switching data collected from actual purchase behavior is short of explanation why consumers consider different set of brands. Considering above problems, main purpose of this study is to analyze market structure for durable goods with consideration set. The author uses exploratory approach and latent class clustering to identify market structure based on heterogeneous consideration set among consumers. Then the relationship between some factors and consideration set formation is analyzed. Some benefits and two demographic variables – age and income – are selected as factors based on consumer behavior theory. The author analyzed USA automotive market with top 11 brands using exploratory approach and latent class clustering. 2,500 respondents are randomly selected from the total sample and used for analysis. Six models concerning market structure are established to test. Model 1 means non-structured market and model 6 means market structure composed of six sub-markets. It is exploratory approach because any hypothetical market structure is not defined. * Business Administration, Korea Nazarene University The result showed that model 1 is insufficient to fit data. It implies that USA automotive market is a structured market. Model 3 with three market structures is significant and identified as the optimal market structure in USA automotive market. Three sub markets are named as USA brands, Asian Brands, and European Brands. And it implies that country of origin effect may exist in USA automotive market. Comparison between modal classification by derived market structures and probabilistic classification by research model was conducted to test how model 3 can correctly classify respondents. The model classify 97% of respondents exactly. The result of this study is different from those of previous research. Previous research used confirmatory approach. Car type and price were chosen as criteria for market structuring and car type-price structure was revealed as the optimal structure for USA automotive market. But this research used exploratory approach without hypothetical market structures. It is not concluded yet which approach is superior. For confirmatory approach, hypothetical market structures should be established exhaustively, because the optimal market structure is selected among hypothetical structures. On the other hand, exploratory approach has a potential problem that validity for derived optimal market structure is somewhat difficult to verify. There also exist market boundary difference between this research and previous research. While previous research analyzed seven car brands, this research analyzed eleven car brands. Both researches seemed to represent entire car market, because cumulative market shares for analyzed brands exceeds 50%. But market boundary difference might affect the different results. Though both researches showed different results, it is obvious that country of origin effect among brands should be considered as important criteria to analyze USA automotive market structure. This research tried to explain heterogeneity of consideration sets among consumers using benefits and two demographic factors, sex and income. Benefit works as a key variable for consumer decision process, and also works as an important criterion in market segmentation. Three factors - trust/ safety, image/fun to drive, and economy - are identified among nine benefit related measu... 시장구조 분석에서 흔히 사용되는 상표전환 자료는 비내구재 분석에 적절한 방법이 될 수 있으나 자동차 같이 사용연한이 장시간인 내구재의 경우에는 소비자의 상표에 대한 선호도가 변할 수 있어 상표전환 자료의 사용에 문제가 있다. 따라서 경쟁을 잘 포착할 수 있는 다른 접근이 필요하다. 본 연구는 이에 대한 대안으로 상표간 경쟁 자료로써 고려상표군을 이용하여 자동차 시장의 구조를 Latent Class 군집분석을 활용한 탐색적 검증방법으로 분석하였다. 또한 소비자 행동분석에 근거하여 상표간 경쟁의 근간을 이루는 고려상표군 형성에 영향을 미치는 인자들을 밝히는데 중점을 두었다. 미국 자동차 시장을 대상으로 분석한 결과, 시장은 상표 원산지 효과에 의해 구분되었다. 즉, 미국 상표, 유럽 상표, 그리고 아시아 상표 등으로 시장이 구분되었다. 또한 각 시장구조 내 소비자들의 고려상표군 형성에 신뢰성/안전, 이미지/즐거움, 경제성 등의 편익과 성별, 소득 등 개인적 요인이 영향을 미치는 것으로 나타났다.

국내 콩관련 논문 : 포장두부의 저장성에 미치는 열처리 효과

이서구,김창식 한국콩연구회 1993 한국콩연구회소식 Vol.74 No.-