• 방송공학회논문지
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• 제13권6호
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• pp.849-858
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• 2008

본 논문에서는 열화된 영상의 화질을 평가함에 있어서 원본 영상을 참조할 필요가 없는 객관적인 평가 방법을 제안한다. 제안하는 알고리듬은 블록 기반의 손실 부호화 과정에서 발생 가능한 블록형 잡음 및 뭉개짐 현상의 정도를 정량화하며, 이와 함께 강한 에지 주변에서 특징적으로 나타나는 물결형 떨림, 계단형 떨림 및 모자이크 잡음 등을 정량화한다. 그리고 퍼지 적분을 이용하여 각각의 잡음의 정도를 통합하여 최종적인 점수를 계산함으로써 주어진 영상의 화질을 평가한다. 제안 알고리듬에 따라 얻어진 화질 평가 결과는 전문가 집단에 의한 주관적 화질 평가 결과와 높은 유사성을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2529-2543
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• 2019

Scanning electron microscopy (SEM) image can link with the microscopic world through reflecting interaction between electrons and materials. The SEM images are easily subject to blurring distortions during the imaging process. Inspired by the fact that dark channel prior captures the changes to blurred SEM images caused by the blur process, we propose a method to evaluate the SEM images sharpness based on the dark channel prior. A SEM image database is first established with mean opinion score collected as ground truth. For the quality assessment of the SEM image, the dark channel map is generated. Since blurring is typically characterized by the spread of edge, edge of dark channel map is extracted. Then noise is removed by an edge-preserving filter. Finally, the maximum gradient and the average gradient of image are combined to generate the final sharpness score. The experimental results on the SEM blurred image database show that the proposed algorithm outperforms both the existing state-of-the-art image sharpness metrics and the general-purpose no-reference quality metrics.

• 한국전기전자재료학회논문지
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• 제20권10호
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• pp.912-917
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• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

• 한국학교ㆍ지역보건교육학회지
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• 제17권1호
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• pp.101-112
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• 2016

Objectives: The purpose of this study was to examine the association between participation in physical activities (PA) and subjective well-being. Methods: We analyzed the data from Korean Youth Risk Behavior Web-based Survey, 2013 containing 36,655 and 35,780 for male and female students respectively. Study variables included PA, participation in physical education class, participation in team sports and subjective well-being. Control variables were school type, socio-economic status, level of parent education, living with parent, academic performance, delinquent behaviors, depression and perceived health. For this study, descriptive analysis, Chi-square test, and multivariate logistic regression analysis were performed. Results: Among boys, after adjusting for control variables, PA (past 7 days 0 time reference group vs. over 4 times: OR 1.306), physical education class (past 7 days 0 time reference group vs. over 3 times: OR 1.140), and team sports (no team reference group vs. 2 team: OR 1.206) were associated with subjective well-being. Among girls, control variables were adjusted. PA (past 7 days 0 time reference group vs over 4 times: OR 1.244), physical education class (past 7 days 0 time reference group vs. over 3 times: OR 1.161), and team sports (no team reference group vs. 2 team: OR 1.181) were associated with subjective well-being. Conclusions: Participation in physical activities may help adolescent promote their life satisfaction. Thus, education experts should develop various exercise curriculums to encourage participation in physical activities.

• Earthquakes and Structures
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• 제11권6호
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• pp.1027-1041
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• 2016

Different incident angles of ground motions have been considered to evaluate the relationship between floor rotation and torsional irregularity coefficient. The issues specifically addressed are (1) variability in torsional irregularity coefficient and floor rotations with varying incident angles of ground motion (2) contradictory relationship between floor rotation and torsional irregularity coefficient. To explore the stated issues, an evaluation based on relative variation in seismic response quantities of linear asymmetric structure under the influence of horizontal bi-directional excitation with varying seismic orientations has been carried out using response history analysis. Several typical earthquake records are applied to the structure to demonstrate the relative variations of floor rotation and torsional irregularity coefficient for different seismic orientations. It is demonstrated that (1) Torsional irregularity coefficient (TIC) increases as the story number decreases when the ground motion is considered along reference axes of the structure. For incident angles other than structure's reference axes, TIC either decreases as the story number decreases or there is no specific trend for TIC. Floor rotation increases in proportion to the story number when the ground motion is considered along reference axes of structure. For incident angles other than structure's reference axes, floor rotation either decreases as the story number increases or there is no specific trend for floor rotation and (2) TIC and floor rotation seems to be approximately inversely proportional to each other when the ground motion is considered along reference axes of the structure. For incident angles other than structure's reference axes, the relationship can even become directly proportional instead of inversely proportional.

• 한국건강관리협회지
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• 제1권1호
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• pp.19-20
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• 2003

In Korea association of health promotion(KHAP) there are fourteen laboratories in branch offices and one laboratory in headquarter office. To standardize the reference ranges of all laboratories of KAHP, they have been newly calculated from the laboratory data perfomed during the previous yearsby statistical metod annually for the period of 2000 through2003 so far. The referance ranges of total 56 test items were assigned. Among these there were eight test items that needed referance ranges by age groups and nine test items that needed reference rages by gender. The age grouping was into six groups : baby (0-3y), children(4-12y), adolescent(13-18y), adult(19-64y), younger elderly(19-64y), older elderly(over 80y) with references of statics in Medical Informatics and WHO classification. All the data collected were statistically analyzed with SAS 6.04 for Gaussian distribution that had been repeated two or three times after trimming out the the tests showed Gaussian distribution. Subsequently, Thereference ranges were defined in the rage from the point of lower 2.5% to the point of higher 97.5%. And in case the lower range could be "0", the reference ranges were defined in the range of 0 to 95%. Fifteen laboratoried troughout Korea of KAHP currently have standarzed reference rages of the tests that they perform. This means the patient data and reference values an be exchangeable among laboratories of KHAP.Annual revise of such reference rages can eventually lead to the level of those representing a standard of the national reference ranges.

• 대한전자공학회논문지SP
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• 제46권3호
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• pp.96-104
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• 2009

본 논문에서는 기준영상에 대한 정보가 없는 무기준(No-reference) 정지영상 객관적 화질 평가 방법을 제안한다. 제안하는 무기준 객관적 화질평가 방법은 인간의 시각체계에서 민감하게 반응하고 화질의 주된 열화 요인인 경계영역의 블록킹과 블러링을 측정하여 수치화 한다. 블록킹 정량화를 위해서, 우선 인접 화소간의 차이를 누적하여 블록킹이 발생하는 위치를 찾고 그 교차점에서 블록킹 현상을 2차원 계단함수로 모델링하여 블록킹의 국소적인 강도를 계산한다. 계산된 국소적 수치들은 적절한 함수화를 통하여 블록킹 수치로 사용된다. 이상적인 영상의 경계는 계단함수임을 가정하면 블러링된 영상에서의 경계의 전이 폭을 계산함으로써 블러링 정도를 예측할 수 있다. 주어진 영상을 다시 Gaussian 블러링 커널을 이용하여 블러링시킨 후 두 영상의 경계 마스크 영상을 이용하여 경계 블록을 결정한다. 경계블록을 수평, 수직, 두 대각선 방향으로 사영하여 얻은 사영신호로부터 국소적 극대 및 극소 위치를 이용하여 경계 전이의 폭을 추정한다. 또한 kurtosis와 SSIM을 이용하여 그 수치를 보정하여 블러링의 수치로 사용한다. 제안한 방법의 객관적 화질 수치는 주관적 화질 수치와 비교해 본 결과 높은 상관관계를 가지는 것을 확인할 수 있다.

• International Journal of Knowledge Content Development & Technology
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• 제8권2호
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• pp.49-65
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• 2018

Are the benefits derived from ICT based reference and information service worth the financial and other commitments devoted to it? In an attempt to answer this, this study delved into finding out the perceived benefits; the rational for ICT based reference services in Nigerian university libraries. The main objectives were to find out the purposes for using ICT facilities in reference services delivery and the perceived benefits derived from using ICT resources in reference and information services. Being a survey, questionnaire was used to collect data from the librarians of twelve (12) universities; two (2) each sampled from the six geopolitical zones of Nigeria. Data was analyzed using frequencies, mean scores and standard deviations. ANOVA statistical analysis was used to test the hypothesis of no significance difference in the benefits derived from ICT based reference services using p-value of 0.05 to calculate the level of significance. Findings showed that librarians and library users made use of ICT facilities for different reference purposes especially to obtain information they need using the internet. Other reference needs for which patrons used the ICT facilities included: - access to current e-books and e - journals, user education and access to global information in other libraries. Provision of current awareness services (CAS) and selective dissemination of information services (SDI), on-line searching using workstations in the library, provision of on-line public access catalogue (OPAC) services, keeping statistics of users of the reference section and compilation of bibliographies. Further findings showed that the librarians and library users derive a lot of benefits from their use of ICT facilities in reference services. The results showed that easy retrieval and dissemination of information to patrons were ranked highest by the librarians amongst others.

• 방송공학회논문지
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• 제21권3호
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• pp.380-390
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• 2016

화질 평가 방법은 그동안 많은 방법이 소개되어 왔다. 특히 우수한 성능을 보여주는 무참조 평가에서 기법에서 발전이 지속되어 왔다. 본 논문에서는 쉬어렛 영역에서 자연영상의 통계적 특성에 기반한 무참조 영상화질 평가 방법을 제안한다. 제안 방법은 쉬어릿 계수의 통계 특성으로부터 왜곡에 민감한 특징을 추출한다. 쉬어렛 변환의 복소수 계수로부터 위상과 크기 특징을 얻어낸다. 또한 쉬어렛 변환은 다양한 스케일로 영상을 분석할 수 있기 때문에, 스케일간의 계수의 의존성에 대한 왜곡의 영향을 분석한다. 화질 예측을 위해서 특징들은 SVM(support vector machine)을 이용하여 영상 왜곡 분류 및 화질 예측에 활용된다. 실험결과는 제안 방법이 주관적 평가와의 높은 상관도를 보여주고, 또한 기존 참조 및 무참조 방법보다 우수한 성능을 보여준다.

• The Journal of Advanced Prosthodontics
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• 제15권6호
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• pp.290-301
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• 2023

PURPOSE. The study aimed to determine the influence of implant angulation on the trueness of multi-unit implant impressions taken through different techniques and strategies. MATERIALS AND METHODS. As reference models, three partially edentulous mandibular models (Model 1: No angulation; Model 2: No angulation for #33, 15-degree distal angulation for #35 and #37; Model 3: No angulation for #33, 25-degree distal angulation for #35 and #37) were created by modifying the angulations of implant analogues. Using a lab scanner, these reference models were scanned. The obtained data were preserved and utilized as virtual references. Three intraoral scanning (IOS) strategies: IOS-Omnicam, ISO-Quadrant, and IOS-Consecutive, as well as two traaditional techniques: splinted open tray (OT) and closed tray (CT), were used to create impressions from each reference model. The best-fit alignment approach was used to sequentially superimpose the reference and test scan data. Computations and statistical analysis of angular (AD), linear (LD), and 3D deviations (RMS) were performed. RESULTS. Model type, impression technique, as well as interaction factor, all demonstrated a significant influence on AD and LD values for all implant locations (P < .05). The Model 1 and SOT techniques displayed the lowest mean AD and LD values across all implant locations. When considering interaction factors, CT-Model 3 and SOT-Model 1 exhibited the highest and lowest mean AD and LD values, respectively. Model type, impression technique, and interaction factor all revealed significant effects on RMS values (P ≤ .001). CT-Model 3 and SOT-Model 1 presented the highest and lowest mean RMS values, respectively. CONCLUSION. Splinted-OT and IOS-Omnicam are recommended for multi-unit implant impressions to enhance trueness, potentially benefiting subsequent manufacturing stages.