• 제목/요약/키워드: Quantitative Approaches

검색결과 416건 처리시간 0.024초

국내 건설기업의 아시아 계약실적 구조 분석 (Analyzing the Market Structure of Asian Construction Contracts : A Perspective on Korean Construction Firms)

  • 이강욱
    • 대한토목학회논문집
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    • 제39권5호
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    • pp.623-630
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    • 2019
  • 아시아 건설시장의 전략적 중요성이 높아지면서 기업 간 경쟁이 더욱 치열해지고 있다. 기존의 아시아 건설시장에 대한 연구는 주요 국가로의 진출전략 도출, 분야별 리스크 평가에 대한 정성적 접근이 주류를 이루었던 반면, 다수 기업의 역동적인 경쟁구도를 정량적으로 설명한 연구는 드물었다. 이에 본 연구는 국내 건설기업이 2009년부터 2017년까지 계약을 체결한 3,996건의 프로젝트 정보를 바탕으로 아시아 지역의 계약실적 구조를 분석하였다. 정태적 분석에는 시장 집중도, 동태적 분석에는 시장 이동성 및 불안정성 개념을 각각 활용하였으며, 이에 대한 수학적 모델을 소개하였다. 분석 결과, 정태적 측면에서는 아시아 건설시장에서 국내 상위 기업군의 시장 점유율 집중 현상이 나타나고 있으며, 동태적 측면에서는 산업설비 공종을 제외한 대부분의 경우 시장 지위가 약하고 안정성이 떨어지는 것으로 밝혀졌다. 본 연구에서 제시한 분석 방법론과 결과는 산업 차원의 실적에 대한 체계적 진단을 가능케 하며, 향후 경쟁전략 수립을 위한 기초자료를 제공하였다는 점에서 의의가 있다.

헝거포드 접근법의 행동주의를 넘어서 (Beyond the Behaviorism Embedded in the Hungerford Approach)

  • 이재영
    • 한국환경교육학회지:환경교육
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    • 제15권1호
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    • pp.68-82
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    • 2002
  • My responses to Kim Kyung-Ok's Critique on my critique on the Hungerford approach can be summarized as follows; First, it was argued that possible confusions and misunderstandings around the concept of behavior in REB were mainly caused by Hungerford himself who has used the word in several different ways, from a bunch of overt actions to almost all kinds of responses including cognitive skills, without any clear operational definition of it for more than 20 years. It seems to be needed for future users of the word, 'Behavior' to Prevent unnecessary confusions by providing their operational definition of it. Second, REB is too ambiguous to be a legitimate goal of environmental education and too outcome-oriented to be a meaningful measure for environmental education research. Anyone who accept REB as a goal of EE or a measure for research should clearly suggest procedures and criteria for judging the environmental responsibility of actions under consideration. Third, the Hungerford approach has begun by realizing the limit of a linear traditional behavior change system and has been evolving toward a complex model with dynamic interactions among/between cognitive variables and affective variables. However, it still has one-way structural orientation toward 'Behavior' with no feedbacks. Addition of some feedback processes would make the model more flexible and realistic. Finally, both the Hines model and the Hungeford model were established based on a series of behavioristic studies including three doctoral dissertations equiped with a list of actions which were prejudged to be environmentally responsible by the researchers, not by the learners. What they were primarily interested in was not how mind functions during the learning processes but how learners' behavior can be effectively changed. Considering uncertainty and complexity associated with environmental problems, a great deal of efforts ought to be made toward more context-based and less normative studies applying cognitive psychology and quantitative approaches.

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CFD 기법을 활용한 공기층에 의한 마찰항력 감소 현상 연구 (Study on the Skin-frictional Drag Reduction Phenomenon by Air Layer using CFD Technique)

  • 김희택;김형태;이동연
    • 대한조선학회논문집
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    • 제56권4호
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    • pp.361-372
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    • 2019
  • The flow pattern of air layers and skin-friction drag reduction by air injection are investigated to find the suitable multiphase flow model using unstructured finite-volume CFD solver for the Reynolds-averaged Navier-Stokes equations. In the present computations, two different multiphase flow modeling approaches, such as the Volume of Fluid (VOF) and the Eulerian Multi-Phase (EMP), are adopted to investigate their performances in resolving the two-phase flow pattern and in estimating the frictional drag reduction. First of all, the formation pattern of air layers generated by air injection through a circular opening on the bottom of a flat plate are investigated. These results are then compared with those of MMkiharju's experimental results. Subsequently, the quantitative ratios of skin-friction drag reduction including the behavior of air layers, within turbulent boundary layers in large scale and at high Reynolds number conditions, are investigated under the same conditions as the model test that has been conducted in the US Navy's William B. Morgan Large Cavitation Channel (LCC). From these results, it is found that both VOF and EMP models have similar capability and accuracy in capturing the topology of ventilated air cavities so called'air pockets and branches'. However, EMP model is more favorable in predicting quantitatively the percentage of frictional drag reduction by air injection.

Selection and evaluation of reference genes for gene expression using quantitative real-time PCR in Mythimna separata walker (Lepidoptera: Noctuidae)

  • ZHANG, Bai-Zhong;LIU, Jun-Jie;CHEN, Xi-Ling;YUAN, Guo-Hui
    • Entomological Research
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    • 제48권5호
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    • pp.390-399
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    • 2018
  • In order to precisely assess gene expression levels, the suitable internal reference genes must be served to quantify real-time reverse transcription polymerase chain reaction (RT-qPCR) data. For armyworm, Mythimna separata, which reference genes are suitable for assessing the level of transcriptional expression of target genes have yet to be explored. In this study, eight common reference genes, including ${\beta}$-actin (${\beta}$-ACT), 18 s ribosomal (18S), 28S ribosomal (28S), glyceraldehyde-3-phosphate (GAPDH), elongation fator-alpha ($EF1{\alpha}$), TATA box binding protein (TBP), ribosomal protein L7 (RPL7), and alpha-tubulin (${\alpha}$-TUB) that in different developmental stages, tissues and insecticide treatments of M. separata were evaluated. To further explore whether these genes were suitable to serve as endogenous controls, three software-based approaches (geNorm, BestKeeper, and NormFinder), the delta Ct method, and one web-based comprehensive tool (RefFinder) were employed to analyze and rank the tested genes. The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated according to normalized HSP70, and MsepCYP321A10 gene expression data. We found that the most suitable reference genes for the different experimental conditions. For developmental stages, 28S/RPL7 were the optimal reference genes, both $RPL7/EF1{\alpha}$ were suitable for experiments of different tissues, whereas for insecticide treatments, $28S/{\alpha}-TUB$ were suitable for normalizations of expression data. In addition, $28S/{\alpha}-TUB$ were the suitable reference genes because they have the most stable expression among different developmental stages, tissues and insecticide treatments. Our work is the first report on reference gene selection in M. separata, and might serve as a precedent for future gene expression studies.

비대면 근무에 대한 근로자와 관리자의 인식에 관한 상호지향성 분석 (Co-orientation Analysis of Workers' and Managers' Perceptions on Untact Work)

  • 권호중;민대환
    • 디지털융복합연구
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    • 제19권2호
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    • pp.83-92
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    • 2021
  • 코로나19로 인한 '사회적 거리 두기' 확산에 따라 비대면 근무가 불가피하게 시행되고 있는데, 실효성에 대한 논란이 있어 구성원의 인식을 살펴볼 필요가 있다. 본 연구는 비대면 근무에 관한 기존 문헌 검토 후 쟁점들을 도출하고, 비대면 근무를 경험한 근로자와 관리자를 대상으로 심층 면담을 실시하여 정성적으로 내용을 분석하고, 상호지향성 모델을 적용하여 비교하였다. 두 집단 공통으로 '소통의 어려움'을 가장 많이 지적하였고, 직무만족, 소속감, 일과 삶의 균형 등에 대한 근로자와 관리자의 인식 차이는 발견하지 못했으나, 인사고과 시 불이익에 대해 인식(객관적 일치도, 근로자의 정확도)의 차이를 보였고, 업무 생산성에 대한 인식(근로자의 주관적 일치도)에서도 차이를 보였다. 기존 연구는 비대면 근무의 일반적인 쟁점들을 논의하였지만, 본 연구는 근로자와 관리자의 인식 차이에 초점을 맞추어 조사하고 인식 차이를 완화시킬 방안의 필요성을 제기한 점에 의의가 있으며, 향후 더 많은 근로자와 관리자를 대상으로 하는 정량적 연구로 확장할 필요가 있다.

Anti-tumor activities of Panax quinquefolius saponins and potential biomarkers in prostate cancer

  • He, Shan;Lyu, Fangqiao;Lou, Lixia;Liu, Lu;Li, Songlin;Jakowitsch, Johannes;Ma, Yan
    • Journal of Ginseng Research
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    • 제45권2호
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    • pp.273-286
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    • 2021
  • Background: Prostate carcinoma is the second most common cancer among men worldwide. Developing new therapeutic approaches and diagnostic biomarkers for prostate cancer (PC) is a significant need. The Chinese herbal medicine Panax quinquefolius saponins (PQS) have been reported to show anti-tumor effects. We hypothesized that PQS exhibits anti-cancer activity in human PC cells and we aimed to search for novel biomarkers allowing early diagnosis of PC. Methods: We used the human PC cell line DU145 and the prostate epithelial cell line PNT2 to perform cell viability assays, flow cytometric analysis of the cell cycle, and FACS-based apoptosis assays. Microarray-based gene expression analysis was used to display specific gene expression patterns and to search for novel biomarkers. Western blot and quantitative real-time PCR were performed to demonstrate the expression levels of multiple cancer-related genes. Results: Our data showed that PQS inhibited the viability of DU145 cells and induced cell cycle arrest at the G1 phase. A significant decrease in DU145 cell invasion and migration were observed after 24 h treatment by PQS. PQS up-regulated the expression levels of p21, p53, TMEM79, ACOXL, ETV5, and SPINT1 while it down-regulated the expression levels of bcl2, STAT3, FANCD2, DRD2, and TMPRSS2. Conclusion: PQS promoted cells apoptosis and inhibited the proliferation of DU145 cells, which suggests that PQS may be effective for treating PC. TMEM79 and ACOXL were expressed significantly higher in PNT2 than in DU145 cells and could be novel biomarker candidates for PC diagnosis.

The Effects of Job Crafting on Task and Contextual Performance: Focusing on the Mediating Effect of Work Engagement

  • JIANG, Feng;WANG, Li;YAN, Lei
    • 산경연구논집
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    • 제13권5호
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    • pp.27-40
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    • 2022
  • Purpose: Research on job crafting has thus far focused on how alter job demand and resources behaviors relate to employee task performance. However, job crafting behaviors do not necessarily have an impact only on task performance, but also on employees' contextual performance, a phenomenon that has little research in job crafting research. Therefore, this study aims to investigate the effect of job crafting on task performance or contextual performance and the mediating effect of work engagement between them in the Chinese context. Research design, data and methodology: In order to achieve the above research goals and test the proposed hypotheses, we used a cross-sectional design and a self-administered questionnaire to collect quantitative data from September 8, 2021 to September 27, 2021 among knowledge workers in Shandong Province various financial companies and finally analyzed 211 questionnaires. Descriptive statistics and research model analysis were performed using SPSS 25.0 Version and AMOS 27.0 Version to test the developed hypotheses. Results: The results are as follows; firstly, the study showed that job crafting of employees had a significant positive impact on task performance and contextual performance. Secondly, the higher job crafting of employees, the higher their work engagement. Thirdly, this study showed that work engagement of employees had a positive impact on task performance and contextual performance. Fourthly, we predicted and found that work engagement of employees had a positive mediating effect between job crafting and task performance and a positive mediating effect between job crafting and contextual performance. Overall, this study showed that the proactive job crafting behaviors of employees enhance their engagement for their work, which in turn improves task performance and contextual performance. Conclusions: This paper develops job crafting research by exploring the positive impact of job crafting on employees' task performance or contextual performance through their work engagement. It also proposes that both job crafting behaviors and work engagement are important approaches to improve employees' task performance or contextual performance. Practical implications for organizations, such as increasing employee' work engagement, as well as the limitations and suggestions are concluded for the future research directions.

드론영상과 YOLOv7x 모델을 이용한 활성산불 객체탐지 (Detection of Active Fire Objects from Drone Images Using YOLOv7x Model)

  • 박강현;강종구;최소연;윤유정;김근아;이양원
    • 대한원격탐사학회지
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    • 제38권6_2호
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    • pp.1737-1741
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    • 2022
  • 고해상도 드론영상과 딥러닝 기술을 결합한 활성산불 감시는 이제 초기단계로 다방면의 연구개발을 필요로 한다. 이 단보에서는 드론영상 산불탐지에 아직 사용되지 않았던 state-of-the-art (SOTA) 모델인 You Only Look Once Version 7 (YOLOv7) 기반의 활성산불 객체탐지를 수행하였으며, 동일한 데이터셋을 사용한 선행연구에 비해 F1점수가 약 0.05 향상된 성과를 거두었다. 향후 우리나라에서도 광역적인 산불감시에 적용될 수 있도록 추가적인 기술 개발이 계속 필요할 것이다.

New Sources of Resistance and Identification of DNA Marker Loci for Sheath Blight Disease Caused by Rhizoctonia solani Kuhn, in Rice

  • Pachai, Poonguzhali;Ashish, Chauhan;Abinash, Kar;Shivaji, Lavale;Spurthi N., Nayak;S.K., Prashanthi
    • The Plant Pathology Journal
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    • 제38권6호
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    • pp.572-582
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    • 2022
  • Sheath blight disease caused by the necrotrophic, soilborne pathogen Rhizoctonia solani Kuhn, is the global threat to rice production. Lack of reliable stable resistance sources in rice germplasm pool for sheath blight has made resistance breeding a very difficult task. In the current study, 101 rice landraces were screened against R. solani under artificial epiphytotics and identified six moderately resistant landraces, Jigguvaratiga, Honasu, Jeer Sali, Jeeraga-2, BiliKagga, and Medini Sannabatta with relative lesion height (RLH) range of 21-30%. Landrace Jigguvaratiga with consistent and better level of resistance (21% RLH) than resistant check Tetep (RLH 28%) was used to develop mapping population. DNA markers associated with ShB resistance were identified in F2 mapping population developed from Jigguvaratiga × BPT5204 (susceptible variety) using bulk segregant analysis. Among 56 parental polymorphic markers, RM5556, RM6208, and RM7 were polymorphic between the bulks. Single marker analysis indicated the significant association of ShB with RM5556 and RM6208 with phenotypic variance (R2) of 28.29 and 20.06%, respectively. Co-segregation analysis confirmed the strong association of RM5556 and RM6208 located on chromosome 8 for ShB trait. This is the first report on association of RM6208 marker for ShB resistance. In silico analysis revealed that RM6208 loci resides the stearoyl ACP desaturases protein, which is involved in defense mechanism against plant pathogens. RM5556 loci resides a protein, with unknown function. The putative candidate genes or quantitative trait locus harbouring at the marker interval of RM5556 and RM6208 can be further used to develop ShB resistant varieties using molecular breeding approaches.

Frontal Face Video Analysis for Detecting Fatigue States

  • Cha, Simyeong;Ha, Jongwoo;Yoon, Soungwoong;Ahn, Chang-Won
    • 한국컴퓨터정보학회논문지
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    • 제27권6호
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    • pp.43-52
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    • 2022
  • 사람이 느끼는 피로는 다양한 생체신호로부터 측정이 가능한 것으로 알려져 있으며, 기존 연구는 질병과 관련된 심각한 피로수준을 산정하는데 주된 목적을 두고 있다. 본 연구에서는 피실험자의 영상을 이용하여 딥러닝 기반의 영상 분석 기술을 적용, 피로 여부를 판단하기 위한 모델을 제안한다. 특히 화상 분석에서 통상적으로 사용되는 객체 인식, 요소 추출과 함께 영상 데이터의 시계열적 특성을 고려하여 방법론을 교차한 3개 분석모델을 제시했다. 다양한 피로상황에서 수집된 정면 얼굴 영상 데이터를 이용하여 제시된 모델을 실험하였으며, CNN 모델의 경우 0.67의 정확도로 피로 상태를 분류할 수 있어 영상 분석 기반의 피로 상태 분류가 유의미하다고 판단된다. 또한 모델별 학습 및 검증 절차 분석을 통해 영상 데이터 특성에 따른 모델 적용방안을 제시했다.