• Bulletin of the Korean Mathematical Society
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• v.40 no.2
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• pp.269-279
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• 2003

We prove an empirical LIL for the Kaplan-Meier integral process constructed from the random censorship model under bracketing entropy and mild assumptions due to censoring effects. The main method in deriving the empirical LIL is to use a weak convergence result of the sequential Kaplan-Meier integral process whose proofs appear in Bae and Kim [2]. Using the result of weak convergence, we translate the problem of the Kaplan Meier integral process into that of a Gaussian process. Finally we derive the result using an empirical LIL for the Gaussian process of Pisier [6] via a method adapted from Ossiander [5]. The result of this paper extends the empirical LIL for IID random variables to that of a random censorship model.

• The Korean Journal of Applied Statistics
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• v.34 no.6
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• pp.889-904
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• 2021

This study is a follow-up study of Kang and Kim (2020). In this study, we derive the sample influence functions of the t-statistic which were not directly derived in previous researches. Throughout these results, we both mathematically examine the relationship between the empirical influence function and the sample influence function, and consider a method to approximate the sample influence function by the empirical influence function. Also, the validity of the relationship between an approximated sample influence function and the empirical influence function is verified by a simulation of a random sample of size 300 from normal distribution. As a result of the simulation, the relationship between the sample influence function which is derived from the t-statistic and the empirical influence function, and the method of approximating the sample influence function through the empirical influence function were verified. This research has significance in proposing both a method which reduces errors in approximation of the empirical influence function and an effective and practical method that evolves from previous research which approximates the sample influence function directly through the empirical influence function by constant revision.

• The Journal of the Acoustical Society of Korea
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• v.33 no.3
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• pp.153-162
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• 2014

Empirical prediction method of the acoustic load on the fairing is based on jet experimental data on the basis of similarity principle. Representative empirical prediction method, DSM-II(Distributed Source Method-II), is a distributing source method along the jet plume. But the empirical prediction model is limited to reflect the impingement source in real environment because it is based on the free jet data. So, we propose a empirical prediction method considering the impinging jet effect by adding a impingement source in the existing prediction method. Considering the additional source's displacement, spectrum, strength and directivity, we calculate the acoustic load on the KSR-III(Korean Sounding Rocket-III) rocket and compare the results with the existing method and experiment data.

• International Journal of Highway Engineering
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• v.16 no.1
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• pp.57-62
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• 2014

PURPOSES : Capacity is a main factor of determining the number of lane in highway design or the level of service in road on operation. Previous studies showed that breakdown may occur before capacity is reached, and then it was concluded that capacity is a stochastic value rather than a deterministic one. In general, estimating capacity is based on average over maximum traffic volume observed for capacity state. This method includes the empirical distribution method(EDM) and would underestimate capacity. This study estimated existing empirical methods of estimating stochastic highway capacity. Among the studied methods are the product limit method(PLM) and the selected method(SM). METHODS : Speed and volume data were collected at three freeway bottleneck sites in Cheonan-Nonsan and West Sea Freeway. The data were grouped into a free-flow state or capacity state with speeds observed in the bottlenecks and the upstream. The data were applied to the empirical methods. RESULTS : The results show that the PLM and SM estimated capacity higher than EDM. The reason is that while the EDM is based on capacity observations only, the PLM and SM are based on free-flow high volumes and capacity observations. CONCLUSIONS : The PLM and SM using both free-flow and capacity observations would be improved to enhance the reliability of the capacity estimation.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1292-1301
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• 2001

The mean-line method using empirical models is the most practical method of predicting off-design performance. To gain insight into the empirical models, the influence of empirical models on the performance prediction results is investigated. We found that, in the two-zone model, the secondary flow mass fraction has a considerable effect at high mass flow-rates on the performance prediction curves. In the TEIS model, the first element changes the slope of the performance curves as well as the stable operating range. The second element makes the performance curves move up and down as it increases or decreases. It is also discovered that the slip factor affects pressure ratio, but it has little effect on efficiency. Finally, this study reveals that the skin friction coefficient has significant effect on both the pressure ratio curve and the efficiency curve. These results show the limitations of the present empirical models, and more resonable empirical models are reeded.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.9-17
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• 2017

This paper describes a process of developing commercial real time image recognition system with company. In this paper we will make a system that is combining an empirical kernel map method and conjugate least squares support vector machine in order to represent images in a low-dimensional subspace for real time image recognition. In the traditional approach calculating these eigenspace models, known as traditional PCA method, model must capture all the images needed to build the internal representation. Updating of the existing eigenspace is only possible when all the images must be kept in order to update the eigenspace, requiring a lot of storage capability. Proposed method allows discarding the acquired images immediately after the update. By experimental results we can show that empirical kernel map has similar accuracy compare to traditional batch way eigenspace method and more efficient in memory requirement than traditional one. This experimental result shows that proposed model is suitable for commercial real time image recognition system.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.215-222
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• 2001

Uncertainty study of shear strength characteristics of the marine clays was carried out based ell In-situ tests and laboratory tests on tile south-east coastal region of the Korean peninsula. Theoretical analyses were studied using both tile spherical cavity expansion theory in finite soil mass and the strain path method to determine tile cone factor using the undrained shear strengths obtained by in-situ tests, and the empirical methods in accordance with the ultimate resistance theory were also discussed. Analysis show that the empirical methods suggest more reasonable value than that of theoretical methods in terms of comparing the cone factor estimated using linear regression and frequency distribution analyses. The cone factors obtained by the empirical methods are 18, 15, and 6 respectively, from the results of total cone resistance, effective cone resistance, and excess porewater cone resistance method, and the estimated were similar to those of previous researcher's.

• Asia pacific journal of information systems
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• v.16 no.2
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• pp.1-25
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• 2006

Application of appropriate research methods has assumed an important role in knowledge accumulation endeavors in the scientific research community. The current study reported here summarizes how we used the empirical methods in IS research, what we need to improve in using empirical study as research methodology through the set of comprehensive research guideline. From the survey and review of seminal and classical research guidelines, we developed our own 28 checklist for research design, statistical analysis, and conclusion, which can be commonly applied to all articles that employ inferential statistical methods in IS research. Then, we critically evaluated the usage of empirical research methods in major IS journals by using the checklist, with the goal of improving the quality of academic papers. In this study, we scrutinized four major IS journals which published empirical papers from 1991 to 2000: MIS Quarterly, Journal of MIS, Information Systems Research, and Decision Sciences. As a result of intensive evaluation work, we could highlight many areas that are lagging and call for greater attention with regard to the proper usage of empirical study in IS research. The research findings in this study can be referred as checklist and guideline when IS researcher applies the empirical method.

• Proceedings of the KOR-KST Conference
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• 2007.11a
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• pp.412-417
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• 2007

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.497-502
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• 2010