• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.81-84
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• 2006

다양한 멀티미디어 사용 환경 조건에 적합한 컨텐츠를 제공하기 위해서는 다양한 소비 환경을 반영할 수 있는 스케일러블 비디오의 제공이 필요하다. 이러한 스케일러블 비디오의 경우, 다양한 조합의 프레임 율, SNR, 공간해상도를 가지는 비디오가 가능하므로 사용자에 게 최적의 품질을 제공하는 조합을 결정해야 할 필요가 있다. 따라서 본 논문에서는 프레임율, SNR, 공간해상도 그리고 영상의 모션 속도에 따라 변동할 수 있는 영상 품질을 나타낼 수 있는 새로운 영상 품질 메트릭을 주관적 평가를 통하여 제안한다. 제안한 품질 메트릭은 주관적 품질평가 선호도와의 상관계수(correlation coefficient)가 PSNR과 주관적 품질평가 점수와의 상관계수 평균값에 비해 높은 값을 보였다. 본 논문에서 제안한 품질 메트릭은 다양한 조합의 부호화 조건에 따른 품질측정이 가능하여 제한적인 멀티미디어 소비환경에서 최적의 부호화 조건을 결정할 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.329-331
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• 2021

본 연구에서는 코로나19 관련 연구논문의 연구주제를 탐색하고 동향을 검토하고 있다. 또한 감성분석을 통해 부정적인 어조가 강한 경고가 되는 주제들을 알아본다. 잠재 디리슐레 할당(LDA)를 이용하여 총 8개의 토픽을 발견하 였고, 이를 구조적 토픽 모델링(STM)과 비교하여 비교적 안정적인 결과임을 확인하였다. 또한 k-means 군집 알고리즘을 통해 각 토픽별로 세부 연구주제를 발견하였고 주성분 분석을 이용하여 이를 시각적으로 표현하였다. 감성분석을 통해 각 토픽별 긍정적, 부정적인 단어들을 살펴보고 감성점수를 계산하여 연구논문의 주된 어조를 파악하였는데, 특히 생물 의학 관련, 국제적 역학관계, 심리적 영향과 관련된 연구에서 부정적인 어조가 강한 것으로 나타나 해당 부문에 대해서 주의와 관심이 요구된다. 향후 연구자들이 연구의 방향성을 탐색하고 정책결정자들이 연구지원 사업을 결정하는데 기초자료로 활용될 수 있을 것이다.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.173-182
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• 2020

The government continuously improves the RPS system to expand the supply of renewable energy, but there has been criticism that more environmental aspects should be considered to reduce GHG emission. REC weights are differentiated according to renewable energy sources. Greenhouse gas emission is one of the decisive factors, and its value is set by experts' opinion. This study assigns LCA to get accurate value of GHG emission. The LCA calculates emitted greenhouse gases from entire process of fuel production, transportation, power plant construction, operation, and decommission. This study suggests a method to change the greenhouse gas reduction effect from the existing qualitative method to the quantitative method and evaluates them. As a result, the evaluation score is changed, but the tier interval is so large that it does not affect the REC weight. Therefore, this study suggests the way that directly reflect the greenhouse gas reduction effect in the REC weight.

• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.727-736
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• 2014

The fundamental concerns of this paper are to analyze the effects of some characteristics on the employment of new college graduated students in viewpoint of data visualization. We use individual and department characteristic data of K-university graduated students in 2010. We apply multiple correspondence analysis, decision tree analysis, association rules and social network analysis for data visualization. The results of the analysis are summarized as follows. First, an analysis of the determinants of employment shows that GPA, department category, age and number of majors, recruiting time affect the employment rate. Second, higher GPA and natural category of department positively affect the employment rate. Finally, low age, single major and early recruiting time also positively affect the employment rate.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.259-266
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• 2002

The main issue in software development is the ability of software project effort and cost estimation in the early phase of software life cycle. The regression models for project effort and cost estimation are presented by function point that is a software sire. The data sets used to conduct previous studies are of ten small and not too recent. Applying these models to 789 project data developed from 1990 ; the models only explain fewer than 0.53 $R^2$(Coefficient of determination) of the data variation. Homogeneous group in accordance with project delivery rate (PDR) divides the data sets. Then this paper presents general effort estimation models using project delivery rate. The presented model has a random distribution of residuals and explains more than 0.93 $R^2$ of data variation in most of PDR ranges.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.147-152
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• 2010

The Internet has become a major channel of business marketing and sales, and there is a core competitive object between websites for a high position ranking in search engine results. There are various ways to maintain the high position ranking of website involving the development of componental coding or the expensive investment for the search engine optimization. The purpose of this paper is proposed to identify and rank the negative elements of website visibility to get rid of those elements when website designer designs the webpage. Website can be removed from indices of search engines when they are not satisfied for search engine optimization. The proposed experiments that are identified and ranked the negative elements of website visibility in this paper are based on the theories and experiments of existing website visibility models. The experimental analyses in this paper are scored and normalized based on methodologies of those models and 10 highest negative elements are ranked through the analyses. Therefore when website is designed, these highest negative elements should be avoided so website can not be removed in the indices of search engines.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.462-462
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• 2021

최근 도시화 및 불투수면의 증가와 지하수의 과다한 사용으로 직접유출이 증가하고, 침투량이 감소하며, 하천의 건천화가 발생하고 있다. 이에 환경부에서는 이러한 물순환의 왜곡을 막기위해 물환경보전법상의 물순환율을 정의하고 물순환 관리목표를 설정하였다. 하지만 지역 별 물순환 특성을 반영한 관리계획이 부족하고, 현재 제한된 재원의 효율적 활용을 위해서는 물순환 관리지역에 대한 우선순위 결정도 필요하다. 본 연구에서는 PSR framework를 통해 유역 물순환 평가방법론을 만들고 이를 활용한 지역별 관리계획 및 우선순위를 결정하고자하였다. PSR framework는 지속가능성을 위해 OECD가 개발한 개념 모형이며, Pressure, State, Response 세 가지 요소로 구분해 평가하게된다. PSR framework의 기본 개념은 인간의 활동들이 환경에 압력 (P)를 주고, 이로 인해 자연의 질과 영향 (S)을 미치며, 이에대한 회복을 위해 인식과 행동을 통해 정책과 제도 등을 통해 반응 (R)한다는 것이다. 유역 물순환을 4가지 그룹 (기후, 수문학적, 사회경제학적, 환경적)으로 구분하고 각 그룹 별 평가요소에 대하여 도출하였다. 기후그룹은 강우, 수문학적 그룹은 증발산, 토지이용, 유출특성을, 사회경제학적 그룹은 재정, 사회구조, 기반시설, 정책을, 환경적 그룹은 수질, 수생태계를 선정하였다. 이후 각 요소 별 평가를 위해 다양한 지표를 고려하여 선정하였으며, 각 지표를 PSR framework에 맞춰 재분류하였다. 각 지표를 하나의 점수로 통합하기 위해 지표 별 가중치를 산정하였으며, 이때 연구자의 주관이 반영되지않는 엔트로피 기법을 이용하여 산정하였다. 구한 식을 통해 우리나라 소유역구분을 기준으로 모든 지표를 계산하였으며, 각 지표에 가중치를 적용해 유역 종합점수를 산정하고 유역 별 취약지역 및 취약요소를 평가하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7040-7050
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• 2014

This study examined whether career decision-making self-efficacy, self-resilience, and career maturity in university students affects the job seeking stress. In particular, this study focused on whether career maturity has a mediating effect among career decision-making self-efficacy, self-resilience and job seeking stress. University students have approximately three points in career maturity - the mid-point of a five-point scale, and career decision-making self-efficacy was proved as a variable affecting the career maturity. In addition, self-resilience has no significant effect on career maturity, and a study of the relationship between the career decision-making self-efficacy and job seeking stress revealed a low correlation. In career decision-making self-efficacy affecting job seeking stress, the career decision-making self-efficacy itself has an effect on the job seeking stress but job seeking stress can improve the career maturity. This study, which is related to career maturity, is different from previous studies dealing with only a single dimension for the direct influence.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.89-97
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• 2022

Recently, various problems such as reduced productivity, insufficient inflow of skilled manpower, reduced quality, and concerns about increasing safety accidents have appeared in the domestic construction industry. Stakeholder of construction project are considering the Off-Site Construction (OSC) method rather than the conventional on-site construction as an alternative. Despite the importance of decision making in the early stage of the adoption of OSC, there is a lack of methodologies for rational decision making. In this study, a decision making system has been developed to derive the final construction cost score by deriving the project characteristics, selecting the construction difficulty index, and developing a cost model for each construction method alternatives to calculate the standard construction cost. Using this system, the OSC method can be effectively evaluated in terms of its feasibility in the early stage of construction

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1033-1039
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• 2023

Low-dose chest CT, which is used as a lung screening test, also includes information on coronary artery calcification within the scan range. The purpose of this study was to investigate the usefulness of determining coronary artery calcification using Low-dose chest CT. Those who underwent low-dose chest CT and coronary artery calcification score CT on the same day were eligible. Coronary artery calcium score CT results were divided into 4 groups (Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS) by referring to the Coronary artery calcium score categories and risks. After selecting 30 people each group, five radiotechnologists with more than 15 years of experience in coronary artery calcium measurement retrospectively analyzed the presence or absence of coronary artery calcification in low-dose chest CT images. The results of the five observers' uniform interpretation of the low-dose chest CT image were consistent with the coronary artery calcium score CT results in Low group: 56%, Mild group: 96.6%, Moderate group: 100%, and High group: 100%. appeared. In the Low group, all 5 observers observed calcification in 17 out of 30 cases, and in 7 cases all 5 observers decided that calcification could not be identified. Coronary artery calcification could be observed in 100% of asymptomatic adults with a calcium score of 15 or higher in low-dose chest CT scans. The minimum calcium score that can be identified is 1, and it was found that even very small calcifications can be identified when the subject's body size is small or the scan is performed at a time when heart movement is minimal.