• 한국농림기상학회지
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• 제19권3호
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• pp.93-101
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• 2017

2011-2015년까지 경남 하동군 악양 집수역의 해발고도 8~1,073m 범위에 설치된 10개 무인기상관측기에서 0600, 1500 기온 관측값을 수집하여 월별 표준편차를 계산하고, 소기후모형으로부터 예측된 기온의 표준편차 결과를 함께 비교하여 미관측 지점의 추정기술에 실효성이 있는지 평가하였다. 소기후모형에 따른 예측값은 월별 0600, 1500 기온의 표준편차를 각각 88%, 86% 정도 설명할 수 있었지만, 전반적으로 과소추정하는 경향이었다. 겨울철과 여름철에 나타나는 낮은 고도 대비 해발고도가 높아질수록 변이가 작아지거나 커지는 방향성에 있어서 관측값과는 반대양상으로 나타나 당초 기대와는 다른 결과를 보였다. 또 다른방법으로 월별 기온 표준편차와 지형간의 관계를 정량화하여 임의지역의 지형특성과 종관규모 수준의 기온자료 만으로 표준편차 분포를 예측할 수 있을지 회귀분석을 수행하였다. 회귀모형은 해발고도편차에 따라 보정된 월별 기온 외에, 경사도와 경사향 등 기본적인 지형인자와 온난대효과와 냉기집적효과, 개방도 등의 기온과 관련된 변수들을 고려하여 월별로 표준편차를 가장 잘 설명할 수 있는 변수를 1~3개까지 선발하여 만들어졌으며, 월별 결정계수는 0.46부터 0.98 범위로 나타났다. 회귀모델을 이용해 기온이 관측되지 않는 임의지역의 표준편차를 지형변수의 최소-최대값 유효범위 내에서 월별로 예측한다면 70% 수준의 추정능력으로 공간변이 분포도를 나타낼 수 있을 것으로 예상된다.

• 품질경영학회지
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• 제50권3호
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• pp.473-490
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• 2022

Purpose: The purpose of this study is to propose a new useful suggestion to monitor the stability of process by developing a stability ratio or index related to investigating how well the process is controlled or operated to the specified target. Methods: The proposed method to monitor the stability of process is building up a new measure index which is making up for the weakness of the existing index in terms of short or long term period of production. This new index is a combined one considering both stability and capability of process to the specification limits. We suppose that both process mean and process variation(or deviation) are changing on time period. Results: The results of this study are as follows: regarding the stability of process as well as capability of process, it was shown that two indices, called SI(stability index) and PI(performance index), can be expressed in two-dimensional X-Y graph simultaneously. This graph is categorized as 4 separated partitions, which are characterized by its numerical value intervals of SI and PI which are evaluated by test statistics. Conclusion: The new revised index is more robust than the existing one in investigating the stability of process in terms of short and long period of production, even in case both process mean and variation are changing.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.192-199
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• 2006

This paper presents an improved anti-islanding algorithm for utility interconnection of multiple distributed fuel cell powered generations (DFPGs). A cross-correlation method is proposed and implemented in conjunction with the anti-islanding algorithm developed in the previous work [I]. While the power control algorithm continuously perturbs $({\pm}5%)$ the reactive power supplied by the DFPG, the proposed algorithm calculates the cross-correlation index of a rate of change of the frequency deviation with respect to $({\pm}5%)$ the reactive power to confirm islanding. If this index is above 50%, the algorithm further initiates $({\pm}10%)$ the reactive power perturbation and continues to calculate the correlation index. If the index exceeds 80%, the occurrence of islanding can be confirmed. The proposed method is robust and capable of detecting the occurrence of islanding in the presence of several DFPGs, which are independently operating. Viability of the cross-correlation method is verified by the simulation. Experimental results are presented to support the findings of the proposed method.

• 대한원격탐사학회지
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• 제32권4호
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• pp.339-351
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• 2016

For the safety of sea, it is important to monitor sea fog, one of the dangerous meteorological phenomena which cause marine accidents. To detect and monitor sea fog, Moderate Resolution Imaging Spectroradiometer (MODIS) data which is capable to provide spatial distribution of sea fog has been used. The previous automatic sea fog detection algorithms were focused on detecting sea fog using Terra/MODIS only. The improved algorithm is based on the sea fog detection algorithm by Wu and Li (2014) and it is applicable to both Terra and Aqua MODIS data. We have focused on detecting spring season sea fog events in the Yellow Sea. The algorithm includes application of cloud mask product, the Normalized Difference Snow Index (NDSI), the STandard Deviation test using infrared channel ($STD_{IR}$) with various window size, Temperature Difference Index(TDI) in the algorithm (BTCT - SST) and Normalized Water Vapor Index (NWVI). Through the calculation of the Hanssen-Kuiper Skill Score (KSS) using sea fog manual detection result, we derived more suitable threshold for each index. The adjusted threshold is expected to bring higher accuracy of sea fog detection for spring season daytime sea fog detection using MODIS in the Yellow Sea.

• 한국환경과학회지
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• 제23권9호
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• pp.1537-1549
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• 2014

The objectives of this study were to analyze reservoir trophic state, based on Trophic State Index (TSI), spatial variation patterns of three zones (riverine, transition, and lacustrine zone), and empirical models through 20-years long-term data analysis. Trophic variables of TP and CHL-a were highest during the summer monsoon, and decreased along the main axis from the riverine to lacustrine zone. In the mean time, TN did not show the trend. Ratios of N:P and Secchi disc transparency (SD) increased from the riverine to lacustrine zone. The analysis of trophic state index (TSI) showed that mean TSI (TP) and TSI (CHL-a) were 62 and 57, respectively, and these values were highest in the transition zone during the summer. This zone should be managed well due to highest lake water pollution. The analysis of Trophic State Index Deviation (TSID) showed that algal growth was primarily limited by light penetration, and this was most pronounced in the monsoon season. The analysis of empirical models showed that the value of $R^2$, based on CHL-SD model, was 0.30 (p < 0.0001) in the transition zone and the $R^2$, based on TP-SD model, was 0.41 (p < 0.0001) in the transition zone.

• 한국의류학회지
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• 제16권1호
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• pp.33-52
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• 1992

In order to get the basic information about the designing and manufacturing of special clothing which is suitable diplegia individuals, taking anthropometic measurements, the di-plegia's body dimension, standard dimension, their correlation, maximum, minimum, the relative deviation graph of Mollison and the body index were obtained. The writer examined their body development and abnormal somatotype and compared the difference with the normal somatotype. The results are as follows: 1 One characteristic of the body of diplegia individuals is that their lower parts are dis- proportionately developed, compared to their upper parts. 2. Diplegia individuals have smaller measurements than those of the normal; height, breadth, and circumference measurments of lower parts. And diplegia individuals have larger measur- ments; breadth and circumference measurements of upper parts, most of the length measur- ements. 3. In body index, diplegia individuals have lager measurments than those of the normals; most of index for stature and chest circumference and waist circumference index. And diplegia individuals have smaller measurments; most of the lower parts. 4. Change of somatotype according to age is unbalanced different from the normal's. 5. For the proportion of diplegia individuals, therefore a different pattern design of ciothing is required based on their special somatotype.

• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.984-990
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• 2013

Pick and placement systems need high speeds and reliability for the position alignment process of semiconductor packages in picking up and placing them on placement trays. Image processing is usually adopted for position aligning where finding out the most suitable method is considered most important aspect of the process. This paper proposes a method for judging the performance of different image processing algorithms based on the PCI (Process Capability Index). The PCI is an index which represents the error distribution acquired from many experimental data. The bigger the index, the more reliable the results or the lower the deviation. Two compared and candidate methods are Hough Transform and PCA (Principal Component Analysis), both of which are very suitable for oblong or rectangular type packages such as BGA's. Comparing the two approaches through a CPI with enough experimental results leads to the conclusion that the PCA is much better than the Hough Transform in not only reliability, but also processing speed.

• 대한치과보철학회지
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• 제29권1호
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• pp.289-303
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• 1991

The purpose of this study is to investigate the correlationship between Pantographic Reproducibility Index(PRI) scores and patterns of mandibular movements by mandibular kinesiograph(MKG) that has been used to diagnose temporomandibular disorders. PRI scores have been measured in normal and symptom groups by tracing Denar mechanical pantograph. Maximum lateral deviation, opening & closing velocity, and clinical rest position of mandibular movements have been analyzed in the same group when the mandible is opened and closed. According to to Helkimo's Dysfunction Index, the students and graduates of College of Dentistry are classified as 6 normal groups and 42 symptom groups. The obtained reslts are as follows : 1. The mean of PRI scores was larger in symptom groups than in normal groups. 2. The mean of maximal laterotrusion in frontal trajectory was larger in symptom groups than in normal groups. 3. There was little significant correlationship observed between PRI scores and patterns of mandibular movements by MKG.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권3호
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• pp.170-174
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• 2008

The measurement of performance of a process considering both the location and the dispersion of information about the process is referred to as the process capacity indices (PCIs) of interest, $C_{pk}$. This information is presented by the mean and standard deviation of the producing process. Linguistic variables are used to express the evaluation of the quality of a product. Consequently, $C_{pk}$ is defined with fuzzy numbers. Lee [Eur. J. Oper. Res. 129(2001) 683-688] constructed the definition of the $C_{pk}$ index estimation presented by fuzzy numbers and approximated its membership function using the "min" - norm based Zadeh's extension principle of fuzzy sets. However, Lee's result was shown to be invalid by Hong [Eur. J. Oper. Res. 158(2004) 529-532]. It is well known that $T_w$ (the weakest t-norm)-based addition and multiplication preserve the shape of L-R fuzzy numbers. In this paper, we allow that the fuzzy numbers are of L-R type. The object of the present study is to propose a new method to calculate the $C_{pk}$ index under $T_w-based$ fuzzy arithmetic operations.

• 대한원격탐사학회지
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• 제26권3호
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• pp.305-316
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• 2010

The MODerate Resolution Imaging Spectroradiometer (MODIS) sensor has 36 bands at 250m, 500m, 1km spatial resolution. However, 500m or 1km MODIS data exhibits a few limitations when low resolution data is applied at small areas that possess complex land cover types. In this study, we produce seven 250m spectral bands by fusing two MODIS 250m bands into five 500m bands. In order to recommend the best fusion method by which one acquires MODIS data, we compare seven fusion methods including the Brovey transform, principle components algorithm (PCA) fusion method, the Gram-Schmidt fusion method, the least mean and variance matching method, the least square fusion method, the discrete wavelet fusion method, and the wavelet-PCA fusion method. Results of the above fusion methods are compared using various evaluation indicators such as correlation, relative difference of mean, relative variation, deviation index, peak signal-to-noise ratio index and universal image quality index, as well as visual interpretation method. Among various fusion methods, the local mean and variance matching method provides the best fusion result for the visual interpretation and the evaluation indicators. The fusion algorithm of 250m MODIS data may be used to effectively improve the accuracy of various MODIS land products.