• 한국안광학회지
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• 제10권2호
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• pp.111-118
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• 2005

시력 검사에 필수적으로 사용되는 시력표는 세계적으로 공인된 시표가 사용되고 있다. 시력표에 사용되는 공인된 시표에는 Landolt 고리와 E 스넬렌 시표가 있으며, 이외에도 아라비아 숫자, 한글, 그림 시표 등을 사용하고 있다. 한국에서는 과거부터 한천석 시력표가 멀리 쓰이고 있으며, 이후 청산 시력표, 진용한 시력표 등의 벽걸이형 시력표가 사용되고 있다. 하지만 이러한 벽걸이형 시력표는 조도에 따라 검사결과가 달라질 수 있는 등, 시력검사를 함에 있어 여러 가지 문제점들이 지적되었다. 이러한 문제점을 해결하기 위하여 지금은 자동화 디지털화 된 빔 프로젝트 형태의 투영식시력표가 등장되었다. 이는 높은 해상도를 일정하게 유지하고 다양한 차트를 제공하여 검사자가 효율적으로 검안을 할 수 있는 자동화된 total 검안 시스템으로써 각광받고 있다. 본 연구에서는 이러한 빔 프로젝트 형태의 투영식시력표의 정확도를 측정하고 과거 널리 사용되었던 일반 시력표의 차이점을 실험하였다. 실험결과 빔 프로젝트를 사용했을 경우, Landolt 고리를 이용하여 측정한 시력과 비교하여 1단계 높게 읽는 경우가 10%, 2단계 높게 읽는 경우가 2%였으며, 일반시력표의 경우 1단계 높게 읽는 경우가 12%, 2단계 높게 읽는 경우가 4%로 나타났다.

• 설비공학논문집
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• 제10권6호
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• pp.666-673
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• 1998

Solubilities (LiBr+$CaC1_2$) in water were measured at temperatures form 267.51 to 306.17K for $CaC1_2$ (LiBr+$CaC1_2$)=0.24 by mole. Experimental data were correlated with polynomial equations. Average absolute deviations between the measured and calculated values were 0.31% at concentration smaller than 60wt% and 0.41% at concentration larger than 60wt%, respectively. Vapor pressures were measured at temperatures from 296.75 to 436.75K and concentrations from 40 to 70wt%. Vapor pressure data were fitted to a Antoine-type equation and average absolute deviation was 2.98%. The P-T-X chart and H-T-X chart of $H_2O$/(LiBr+$CaC1_2$) system were constructed by using the correlation equations of solubility, vaper pressure, and heat capacity. The P-T-X chart indicates that $H_2O$/(LiBr+$CaC1_2$) system has potential as a possible working fluid for air-cooled absorption chillers.

• 대한산업공학회지
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• 제29권1호
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• pp.21-31
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• 2003

Determination of operational dimensions and tolerances is complex if there exist inconsistencies between operational and design specifications. Dimension and tolerance charts (D&T charts) have been used to establish the relationships among operational dimensions in complex machining. This chart proves that individual operations can be harmonized when they are interconnected. However, it is hard to generate the chart manually. Because operational dimensions and tolerances must meet the design specifications, the dimensions and tolerances of interconnected operations have to be verified serially for economical operations. In this paper, the chart is automatically generated from the interconnected operations. More importantly, all operational dimensions and tolerances displayed in the chart have been verified by using LP to meet the design specifications. Finally, the chart is converted to an operational routing sheet that contains a detailed process plan along with cutting speed, feed rate, and operational references based on material hardness, surface finish, and tool nose radius.

• International Journal of Contents
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• 제14권3호
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• pp.46-52
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• 2018

The objective of this study was to determine the status of star chart game applications in the Google play store in Korea. The share of game genres in paid and free star charts of game applications was searched. Also, the average reviewer's rating, average number of reviews, and average age rating based on the genre of paid and free star charts of game applications, and the average price of paid applications based on genre were analyzed. Hypothesis tests for the differences in average reviewer's rating, average number of reviews, average age rating according to the genre of game applications were performed. Also, hypothesis tests for the differences in average reviewer's rating, average number of reviews, average age rating between the paid and free game applications along with the hypothesis test for the differences in price according to the genre of paid game applications were performed. Lastly, hypothesis tests for the correlation between the start chart ranking and number of reviews in association with the correlation between the start chart ranking and reviewer's rating were performed. Statistically significant differences in average reviewer's rating, average number of reviews, average age rating according to the genre of game applications, and between the paid and free game applications were verified. However, the correlation between the start chart ranking and number of reviews in association with the correlation between the start chart ranking and reviewer's rating were not statistically significant.

• Communications for Statistical Applications and Methods
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• 제19권5호
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• pp.685-696
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• 2012

These days the interest of quality leads to the necessity of control charts for monitoring the process in various fields of practical applications. The $\overline{X}$ chart is one of the most widely used tools for quality control that also performs well under the normality of quality characteristics. However, quality characteristics tend to have nonnormal properties in real applications. Numerous recent studies have tried to find and explore the performance of $\overline{X}$ chart due to non-normality; however previous studies numerically examined the effects of non-normality and did not provide any theoretical justification. Moreover, numerical studies are restricted to specific type of distributions such as Burr or gamma distribution that are known to be flexible but can hardly replace other general distributions. In this paper, we approximate the false alarm rate(FAR) of the $\overline{X}$ chart using the Edgeworth expansion up to 1/n-order with the fourth cumulant. This allows us to examine the theoretical effects of nonnormality, as measured by the skewness and kurtosis, on $\overline{X}$ chart. In addition, we investigate the effect of skewness and kurtosis on $\overline{X}$ chart in numerical studies. We use a skewed-normal distribution with a skew parameter to comprehensively investigate the effect of skewness.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 1993년도 제5회 한글 및 한국어정보처리 학술대회
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• pp.15-24
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• 1993

한국어는 구문요소의 문법기능이 표면구조상에 명시되는 구문특성을 갖고 있다. 이러한 특성은 한국어의 문법체계가 feature중심으로 전개되고 있음을 의미한다. 한국어에서의 feature 특성과 이진 결합 관계를 중심으로 하는 chart parsing 알고리즘을 제시하고 한국어 chart parser을 구현하였다.

• 품질경영학회지
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• 제44권1호
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• pp.167-180
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• 2016

Purpose: The problem for the traditional control chart is that it is unable to monitor the very small fraction of nonconforming and the underlying distribution is the normal distribution. $Z_p$ control chart is useful where it controls the vert small fraction on nonconforming. In this study, we will design the $Z_p$ control chart in order to use under non-normal process. Methods: $Z_p$ is calculated not by failure rate based on attribute data but using variable data. Control limit for non-normal $Z_p$ control chart is designed based on ${\alpha}$-risk calculated by cumulative distribution function of Burr distribution. ${\beta}$-risk, which is for performance evaluation, obtains in the Burr distribution's cumulative distribution function and control limit. Results: The control limit for non-normal $Z_p$ control chart is designed based on Burr distribution. The sensitivity can be checked through ARL table and OC curve. Conclusion: Non-normal $Z_p$ control chart is able to control not only the very small fraction of nonconforming, but it is also useful when $Z_p$ distribution is non-normal distribution.

• 산업경영시스템학회지
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• 제39권2호
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• pp.37-45
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• 2016

Control chart is representative tools of statistical process control (SPC). It is a graph that plotting the characteristic values from the process. It has two steps (or Phase). First step is a procedure for finding a process parameters. It is called Phase I. This step is to find the process parameters by using data obtained from in-controlled process. It is a step that the standard value was not determined. Another step is monitoring process by already known process parameters from Phase I. It is called Phase II. These control chart is the process quality characteristic value for management, which is plotted dot whether the existence within the control limit or not. But, this is not given information about the economic loss that occurs when a product characteristic value does not match the target value. In order to meet the customer needs, company not only consider stability of the process variation but also produce the product that is meet the target value. Taguchi's quadratic loss function is include information about economic loss that occurred by the mismatch the target value. However, Taguchi's quadratic loss function is very simple quadratic curve. It is difficult to realistically reflect the increased amount of loss that due to a deviation from the target value. Also, it can be well explained by only on condition that the normal process. Spiring proposed an alternative loss function that called reflected normal loss function (RNLF). In this paper, we design a new control chart for overcome these disadvantage by using the Spiring's RNLF. And we demonstrate effectiveness of new control chart by comparing its average run length (ARL) with ${\bar{x}}-R$ control chart and expected loss control chart (ELCC).

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1995년도 VTS and IBS 95 The Korean Institute of Navigation 1995년도
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• pp.118-124
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• 1995

This paper describes the research and development of the Electronic Chart Data base and the Electronic Chart Display and Information System(ECDIS) based on the Draft Soecification for ECDIS of IHO by the Research Group on ECDIS of the Ministry of Communicatios of China, The paper also briefly introduces the systems configuration basic function electronic chart data base of China and the future prospects.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.185-192
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• 2004

The goal of this paper is to determine the accurate effective length factor(K factor) for buckling design of plane frames and to point out the practical limitations of the alignment chart which provides the approximate effective length factor. At present, the most general method to obtain K factors is to use the alignment chart which is given in the form of nomograph in LRFD-AISC specification commentaries. However it should be realized that various simplifications and assumptions were used in obtaining the alignment chart. Therefore, a simple but effective method to obtain accurate K-factors through the stability analysis of plane frames is developed in this study. To demonstrate the accuracy and effectiveness of the present scheme, K-factors by system buckling analysis of frames are calculated and compared with those calculated by the alignment chart.