• 한국화재소방학회논문지
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• 제28권3호
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• pp.34-42
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• 2014

본 연구에서는 $CH_4$ 및 $C_3H_8$ 연료의 컵버너 비예혼합화염에서 Swing, Rotation, Lifted 및 Blow-out과 같은 화염 불안정성을 발생시키는 불활성기체($N_2$, Ar, $CO_2$ 및 He)의 농도를 측정하였으며, 소화기준(즉, 화염날림 또는 화염불안정성 개시)에 따른 소화농도의 정량적 차이를 검토하였다. 소화농도의 차이는 부상화염의 발생 그리고 낮은 소화성능의 불활성기체일수록 증가됨을 확인하였다. 소화기준에 따른 소화농도의 최대 차이는 $C_3H_8$-air 비예혼합화염의 최대 연료유속의 조건(1.3 cm/s)에서 약 35%이다. 또한 화염 불안정성의 개시를 기준으로 측정된 소화농도는 정확한 그리고 경제적 설계 농도의 관점에서 유용한 정보를 제공할 것으로 기대된다.

• Korean Journal of Radiology
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• 제20권5호
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• pp.854-861
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• 2019

Objective: To evaluate quantitative magnetic resonance imaging (MRI) parameters for differentiation of cysts from and solid masses in the anterior mediastinum. Materials and Methods: The development dataset included 18 patients from two institutions with pathologically-proven cysts (n = 6) and solid masses (n = 12) in the anterior mediastinum. We measured the maximum diameter, normalized T1 and T2 signal intensity (nT1 and nT2), normalized apparent diffusion coefficient (nADC), and relative enhancement ratio (RER) of each lesion. RERs were obtained by non-rigid registration and subtraction of precontrast and postcontrast T1-weighted images. Differentiation criteria between cysts and solid masses were identified based on receiver operating characteristics analysis. For validation, two separate datasets were utilized: 15 patients with 8 cysts and 7 solid masses from another institution (validation dataset 1); and 11 patients with clinically diagnosed cysts stable for more than two years (validation dataset 2). Sensitivity and specificity were calculated from the validation datasets. Results: nT2, nADC, and RER significantly differed between cysts and solid masses (p = 0.032, 0.013, and < 0.001, respectively). The following criteria differentiated cysts from solid masses: RER < 26.1%; nADC > 0.63; nT2 > 0.39. In validation dataset 1, the sensitivity of the RER, nADC, and nT2 criteria was 87.5%, 100%, and 75.0%, and the specificity was 100%, 40.0%, and 57.4%, respectively. In validation dataset 2, the sensitivity of the RER, nADC, and nT2 criteria was 90.9%, 90.9%, and 72.7%, respectively. Conclusion: Quantitative MRI criteria using nT2, nADC, and particularly RER can assist differentiation of cysts from solid masses in the anterior mediastinum.

• 영어어문교육
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• 제17권1호
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• pp.191-208
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• 2011

The quantitative study investigated perceptions of evaluative criteria in L2 writing between two groups - learners (N=212) and instructors (N=52) in Korea. Specifically, the purpose of the study is (1) to examine learners' and instructors' perceptions on evaluative criteria in L2 writing and to provide empirical evidence concerning how they respond to a list of them and (2) to ultimately devise appropriate rating criteria applicable to an EFL context like Korea. Analyses of evaluative criteria were conducted using factor analysis and yielded the following results: learner and instructor groups perceived the evaluative criteria differently and weighted them in a different way. For the learner group, the combined elements of grammar and language in use were identified as Factor 1 and mechanics as Factor 2. The results may infer that learners' response patterns are primarily linked to their instructors' writing practice in class, which may largely focus on grammatical knowledge based on lexical use and mechanical accuracy. Similarly, the instructor group acknowledged grammatical knowledge as Factor 1 and lexical use as Factor 2. The first two factors found in both learner and instructor groups indicate that in an EFL context like Korea, the form-then-content way of teaching and learning is still being considered more effective in L2 writing than any other method. Taking into consideration these perceptive similarities and differences between learners and instructors, the categories of evaluative criteria in writing include content and organization, grammar, mechanics, language in use, and flow of the essay, respectively.

• 복식문화연구
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• 제27권4호
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• pp.323-335
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• 2019

Identifying the selection criteria of wedding planners, who are the main human resource that contribute to the overall satisfaction level of a wedding's preparation, can produce important data for the wedding industry as it faces a transition period. To develop a scale for wedding planner selection criteria, preliminary items were prepared based on in-depth interviews with an experienced wedding planner group and a comprehensive review of previous studies, such as studies on selection criteria in the wedding industry and service work similar to wedding planners and wedding planner selection criteria. The preliminary items were tested for content validity using a focus group interview, comprising people in the wedding industry, and were refined accordingly. Then, the definitive quantitative questionnaire items were developed after conducting a preliminary survey. The main survey for this study was conducted using the responses of 295 consumers taking an Internet questionnaire. Exploratory factor analysis, Cronbach's alpha, and confirmatory factor analysis were adopted to develop the scale, which was tested for convergent validity and discriminant validity. This study is academically significant in that it developed a selection criteria scale tailored to wedding planners to address an area that has not been covered in previous studies. It is recommended that future studies conduct empirical analyses using the selection criteria developed in this study to compare influential variables that could affect behavior intention.

• 환경위생공학
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• 제8권2호
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• pp.11-24
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• 1993

Methodology for health risk assessment has been developed by governmental agencies and research institutions in the United States concerning environmental and industrial health such as Environmental Protection Agency, Pood and Drug Administration, and Occupational Safety and Health Administration. The basic concept, process, and scientific rational of the health risk assessment are discussed in order to introduce this field of research for future application to risk assessment and management in Korea. As environmental criteria for most of the environmental carcinogens and nonfarcinogens are set based on the quantitative risk assessment, this quantitative methodology should be emphasized and studied in Korean situation.

• International Journal of Concrete Structures and Materials
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• 제6권2호
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• pp.87-100
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• 2012

The process of selecting a repair material is a typical one of multi-criteria decision-making (MCDM) problems. In this study Analytical Hierarch Process was applied to solve this MCDM problem. Many factors affecting a process to select an optimal repair material can be classified into quantitative and qualitative requirements and this study handled only quantitative items. Quantitative requirements in the optimal selection model for repair material were divided into two parts, namely, the required chemical performance and the required physical performance. The former is composed of alkali-resistance, chloride permeability and electrical resistivity. The latter is composed of compressive strength, tensile strength, adhesive strength, drying shrinkage, elasticity and thermal expansion. The result of the study shows that this method is the useful and rational engineering approach in the problem concerning the selection of one out of many candidate repair materials even if this study was limited to repair material only for chloride-deteriorated concrete.

• Nuclear Engineering and Technology
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• 제43권5호
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• pp.437-446
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• 2011

Siting criteria for nuclear power plants require that faults be characterized as to their potential for generating earthquakes, or that the absence of the potential for these occurrences be demonstrated. Because the definition of active faults in Korea has been applied by the deterministic method, which depends on the numerical age of fault movement, the possibility of inherent uncertainties exists in determining the maximum earthquake from the fault sources for seismic design. In an attempt to overcome these problems this study suggests new criteria and a probabilistic quantitative diagnostic procedure that could estimate whether a fault is capable of generating earthquakes in the near future.

• International Journal of Quality Innovation
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• 제9권3호
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• pp.145-162
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• 2008

Since the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China published the GB/T19580-2004: Criteria for Excellence Performance of China, many enterprises in China have adopted the Criteria to enhance their organization business management and to assess or self-assess organization performance. On the bases of both the Criteria for Excellence Performance of China and the survey data from China Association for Quality (CAQ), this paper systematically explores the relationships among 'leadership', 'strategy planning', 'customer and market', 'information, analysis and improvement', 'resources management', 'process management', and 'performance results' by using structural equations modeling and validates some of the anecdotal beliefs in quality management. This quantitative analysis provides a guideline for organizations in China to identify causal linkage among core value of total quality management and to identify strengths, deficiency, and opportunities to enhance competitive advantages and ensure the future business success.

• 경영과학
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• 제17권3호
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• pp.97-118
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• 2000

This paper proposes an evaluation model for internet shopping mall business by defining its characteristics and evaluation criteria. We analyzed the characteristics of internet shopping mall business environments and classified the business into four major categories. We derived the evaluation criteria which can evaluated all categories comprehensively. The proposed criteria are cost, netizen, technology, transaction, and marketing, each of which gives a significant impact on the business profitability. Based on these criteria, a quantitative evaluation method was developed. We also proposed a penta-classification scheme which can be used to identify the overall characteristics shape of each internet shopping mall business site. An actual application of our evaluation model was illustrated in order to show that our proposed model may be used in the real business sites.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.131-134
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• 1996

Application of machine learning to scheduling problems has focused on improving system performance based on opportunistic selection among multitudes of simple rules. This study proposes a new method of learning scheduling rules, which first establishes qualitatively meaningful criteria and quantitatively optimizes the use of them, a similar way as human scheduler accumulate their expertise. The weighting of these criteria is trained in response to the system states through simulation. To mimic human quantitative feelings, distributed fuzzy sets are used for assessing the system state. The proposed method was applied to job dispatching in a simulated FMS environment. The job-dispatching criteria used were the length of the processing time of a job and the situation of the next workstation. The results show that the proposed method can develop efficient and robust scheduling strategies, which can also provide understandable and usable know-hows to the human scheduler.