• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.174-183
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• 2018

In the industrial fields, the process capability index has been using to evaluate the variation of quality in the process. The traditional process capability indices such as $C_p$, $C_{pk}$, $C_{pm}$ and $C^+_{pm}$ have been applied in the industrial fields. These traditional process capability indices are mainly applied in the univariate analysis. However, the main streams in the recent industry are the multivariate manufacturing process and the multiple quality characteristics are corrected each other. Therefore, the multivariate statistical method should be used in the process capability analysis. The multivariate process indices need to be enhanced with more useful information and extensive application in the recent industrial fields. Hence, the purpose of the study is to develop a more effective multivariate process index ($MC_{pI}$) using the multivariate inverted normal loss function. The multivariate inverted normal loss function has the flexibility for the any type of the symmetrical and asymmetrical loss functions as well as the economic information. Especially, the proposed modeling method for the multivariate inverted normal loss function (MINLF) and the expected loss from MINLF in this paper can be applied to the any type of the symmetrical and asymmetrical loss functions. And this modeling method can be easily expanded from a bivariate case to a multivariate case.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.4
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• pp.171-180
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• 2016

As social networking services such as twitter become increasingly popular, data streams are widely prevalent these days. In order to search data accumulated from data streams efficiently, the use of an index structure is essential. In this paper, we propose an update-efficient, disk-based inverted index structure for efficient keyword search on data streams. When new data arrive at the data stream, the index needs to be updated to incorporate the new data. The traditional inverted index is very inefficient to update in terms of disk I/O, because all index data stored in the disk need to be read and written to the disk each time the index is updated. To solve this problem, we divide the whole inverted index into a sequence of inverted indices with exponentially increasing size. When new data arrives, it is first inserted into the smallest index and, later, the small indices are merged with the larger indices, which leads to a small amortize update cost for each new data. Furthermore, when indices stored in the disk are merged with each other, we minimize the disk I/O cost incurred for the merge operation, resulting in an even smaller update cost. Through various experiments, we compare the update efficiency of the proposed index structure with the previous one, and show the performance advantage of the proposed structure in terms of the update cost.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.49-50
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• 2005

This paper presents a scheme for state observer-based stabilization control of inverted pendulum systems. The feedback gain matrices of both the state feedback controller and the state observer are obtained by a real-coded genetic algorithm(RCGA) such that the given performances indices are minimized.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.106-114
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• 2019

Recently, the manufacturing process system in the industrial field has become more and more complex and has been influenced by many and various factors. Moreover, these factors have the dependent correlation rather than independent of each other. Therefore, the statistical analysis has been extended from the univariate method to the multivariate method. The process capability indices have been widely used as statistical tools to assess the manufacturing process performance. Especially, the multivariate process indices need to be enhanced with more useful information and extensive application in the recent industrial fields. The various multivariate process capability indices have been studying by many researchers in recent years. Hence, the purpose of the study is to compare the useful and various multivariate process capability indices through the simulation. Among them, we compare the useful models of several multivariate process capability indices such as $MC_{pm}$, $MC^+_{pm}$ and $MC_{pl}$. These multivariate process capability indices are incorporates both the process variation and the process deviation from target or consider the expected loss caused by the process deviation from target. Through the computational examples, we compare these process capability indices and discuss their usefulness and effectiveness.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.462-467
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• 2007

The design and synthesis of a state feedback controller assumes the feedback of all state variables of the system. However, some state variables are not physical quantifies so that sensors may not be available, or may be too expensive to measure. Hence, a state observer can be an alternative to estimate unmeasurable state variables. This paper therefore presents a scheme for state observer-based stabilization control of inverted pendulum systems. The feedback gain matrices of both the state feedback controller and the state observer are tuned by real-coded genetic algorithms(RCGAs) such that the given performance indices are minimized. The proposed method is demonstrated through simulations.

• East Asian Economic Review
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• v.28 no.2
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• pp.221-244
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• 2024

This study examines how the independence of monetary policy changes in situations where the interest rate differential between domestic and foreign rates inverts, utilizing the trilemma indices. For analysis, this paper uses the trilemma indices developed by Kim et al. (2017) to analyze the relationship between the monetary policy independence index and the other two trilemma indices, namely the capital account openness index and the exchange rate stability index, across 45 countries from 2002 to 2018. The analysis reveals that the trilemma's validity is contingent. In particular, no statistically significant negative correlation was found between the monetary policy independence index and exchange rate stability index during periods of interest rate differential inversion. A positive correlation emerges between exchange rate stability and the independence of monetary policy, particularly when the inverted interest rate differential exceeds a certain threshold. This situation, where the exchange rate remains stable despite low domestic interest rates, implies that the central bank is effectively managing monetary policy to appropriately respond to economic conditions, which is reflected in the monetary policy independence index.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.7
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• pp.1-10
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• 1982

This paper derives the algorithm to estimate the operating cost, its marginal cost, and the reliability indices for the long term planning of power system. Treating the load duration curve and the system in the stochastic sense takes the place of the inverted load duration curve, effective load duration curve, and the numerical integration in the conventional methods. The time and accuracy of computation are substantially improved due to the fact that all expressions are represented by simple analytic form instead of the existing recursive form.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.433-437
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• 2015

We show the results of a time series analysis of the long-term light curves of four blazars. 3C 279, 3C 345, 3C 446, and BL Lacertae. We used densely sampled light curves spanning 32 years at three frequency bands (4.8, 8, 14.5 GHz), provided by the University of Michigan Radio Astronomy Observatory monitoring program. The spectral indices of our sources are mostly flat or inverted (-0.5 < ${\alpha}$ < 0), which is consistent with optically thick emission. Strong variability was seen in all light curves on various time scales. From the analyses of time lags between the light curves from different frequency bands and the evolution of the spectral indices with time, we find that we can distinguish high-peaking flares and low-peaking flares according to the Valtaoja et al. classification. The periodograms (temporal power spectra) of the light curves are in good agreement with random-walk power-law noise without any indication of (quasi-)periodic variability. We note that random-walk noise light curves can originate from multiple shocks in jets. The fact that all our sources are in agreement with being random-walk noise emitters at radio wavelengths suggests that such behavior is a general property of blazars. We are going to generalize our approach by applying our methodology to a much larger blazar sample in the near future.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.544-550
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• 2008

This study conducted a survey on the ecosystem of Wonju stream from May until November in 2004 and made an health assessment of Wonju stream using family biotic indices(FBI) and physical habitat assessment(PHA) of the aquatic insects. Through this survey, aquatic insects covering 8 orders, 37 families, 62 genuses, and 92 species were observed at 9 stations along Wonju stream. In terms of family biotic indices, it was confirmed that station 1,2 and 3 were maintaining the healthiest stream ecosystem with the value ranging from 4.55 to 4.82. In addition, station 2 was found to have the best habitat environment in the correlation between physical habitat assessment and family biotic indices with its value of 100 and 4.82, respectively. However, station 7 and 9 showed the lowest habitat environment with the value of 45, 6.17 and 45, 6.97, respectively. posing the need for improvement in PHA; further, station 7 and 9 showed inverted correlationship between PHA and FBI.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.207-213
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• 2015

Background Pincer nail deformity is a transverse overcurvature of the nail. This study aimed to define the anatomical characteristics of pincer nail deformity and to evaluate the surgical outcomes. Methods A retrospective review was conducted on 20 cases of pincer nail deformity of the great toe. Thirty subjects without pincer nail deformity or history of trauma of the feet were selected as the control group. Width and height indices were calculated, and interphalangeal angles and base widths of the distal phalanx were measured with radiography. We chose the surgical treatment methods considering perfusion-related factors such as age, diabetes mellitus, kidney disease, and peripheral vascular disease. The zigzag nail bed flap method (n=9) and the inverted T incision method (n=11) were used to repair deformities. The outcomes were evaluated 6 months after surgery. Results The interphalangeal angle was significantly greater in the preoperative patient group ($14.0^{\circ}{\pm}3.6^{\circ}$) than in the control group ($7.9^{\circ}{\pm}3.0^{\circ}$) (P<0.05). The postoperative width and height indices were very close to the measurements in the control group, and most patients were satisfied with the outcomes. Conclusions We believe that the width and height indices are useful for evaluating the deformity and outcomes of surgical treatments. We used two different surgical methods for the two patient groups with respect to the perfusion-related factors and found that the outcomes were all satisfactory. Consequently, we recommend taking into consideration the circulatory condition of the foot when deciding upon the surgical method for pincer nail deformity.