• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.243-251
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• 2020

In seismic design standards such as KDS 41 17 00 and ASCE 7, three procedures are provided to estimate seismic demands: equivalent lateral force (ELF), response spectrum analysis (RSA), and response history analysis (RHA). In this study, two steel special moment frames (SMFs) were designed with ELF and RSA, which have been commonly used in engineering practice. The collapse probabilities of the SMFs were evaluated according to FEMA P695 methodology. It was observed that collapse probabilities varied significantly in accordance with analysis procedures. SMFs designed with RSA (RSA-SMFs) had a higher probability of collapse than SMFs designed with ELF (ELF-SMFs). Furthermore, RSA-SMFs did not satisfy the target collapse probability specified in ASCE 7-16 whereas ELF-SMFs met the target probability.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.441-445
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• 2004

In this paper, we deal with an inventory model of a multi-stage, serial supply chain system where a single product type and nonstationary customer demand pattern are considered. The retailer and suppliers place their orders according to an echelon-stock based replenishment control policy. We assume that the suppliers can access online information on the demand history and use this information when making their replenishment decisions. Using a reinforcement learning technique, the inventory control parameters are designed to adaptively change as the customer demand pattern is altered, in order to maintain a given target service level. Through a simulation based experiment, we verified that our approach is good for maintaining the target service level.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.475-480
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• 2001

The purpose of this study is to evaluate the validity of seismic performance evaluation using static analysis. For this purpose, Ordinary Moment Resisting Steel Frames(OMRSF) for different heights(3, 6 ,9, 12 story) and seismic zones(Zone 2A, 2B, 3, 4) were designed in compliance to AISC LRFD 1993 Seismic Provisions and NEHRP 1994 Guidelines. Nonlinear Static Procedure(NSP) and Nonlinear Dynamic Procedure(NDP) with a set of ground motion record were used to evaluate seismic demands in OMRSFs. Using the DRAIN-2DX program, this study compares peak displacement demands(Target Displacement) proposed by FEMA 273 with the peak roof displacement demands obtained from the inelastic time history analyses. Based on the results, the validity of procedure of seismic demand evaluation using Target Displacement is discussed.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.1
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• pp.55-62
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• 2016

It is important to select an accurate set of ground motions when conducting linear and nonlinear response history analyses of structures. This study proposes a method for selecting ground motions from a ground motion library with response spectra that match the target response spectrum mean, variance and correlation structures. This study also has addressed the determination of an appropriate value for the weight factor of a correlation structure. The proposed method is conceptually simple and straightforward, and does not involve a simulation algorithm. In this method, a desired number of ground motions are sequentially selected from first to last. The proposed method can be also used for selecting ground motions with response spectra that match the conditional spectrum. The accuracy and efficiency of the proposed procedure are verified with numerical examples.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.2
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• pp.103-112
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• 2016

Resonance occurrence conditions are explored by performing dynamic interaction analysis of arch bridge and KTX trains. The target bridge is a 3D tied-arch bridge having span length of 120m. KTX trains consist of two power carriages, two power and passenger carriages and sixteen passenger carriages. When KTX trains run on the target bridge with the uniform speed of 100 to 500km/h, the dynamic responses of the bridge induced by moving trains are obtained from railway arch bridge-train interaction analysis. Two resonance conditions are presented and whether the resonance phenomena occur or not at the suspicious resonance velocities is rigorously investigated through bridge deflections and accelerations and their FFT analysis.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1314-1323
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• 2018

For nuclear power plants (NPPs) to have long lifetimes, ageing is a major issue. Currently, ageing management for NPP systems is based on correlations built from generic experimental data. However, each system has its own characteristics, operational history, and environment. To account for this, it is possible to resort to prognostics that predicts the future state and time to failure (TTF) of the target system by updating the generic correlation with specific information of the target system. In this paper, we present an application of particle filtering for the prediction of degradation in steam generator tubes. With a case study, we also show how the prediction results vary depending on the uncertainty of the measurement data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1304-1311
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• 2003

Target tracking in a real world situation is difficult problem because of continuous variations in images, huge amounts of data, and high processing speed demands. The problem becomes even harder in the case of sea background. This paper presents an initial study of neural network based method for target detection and tracking in cluttering environment. The approach uses a combination of differential motion analysis, Kohonen self-organizing network and region growing method. The network is capable of detecting the mass-centers of moving objects within one frame. The history of neurons positions in the sequential frames approximates the traces of the targets. The experiments done with the network in simulated environment showed promising results.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.46-51
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• 2006

Dyslipidemia is an important CHD risk factor in diabetic patients. We conducted this study to assess the pattern of dyslipidemia in type 2 diabetes patients, to examine the demographic and clinical factors associated with dyslipidemia and to evaluate attaining within the lipid target goals and treatment strategies. A retrospective analysis was conducted among patents diagnosed type 2 diabetes at outpatient clinic in endocrinology between January 2003 and December 2004. Clinical history and physical examination were reviewed and laboratory data including blood glucose, HbAlc, lipid levels were recorded sequentially at least 1 year. In 882 patients with type 2 diabetes, 437 patients (49.6%) have dyslipidemia and 73% of them (319 patients) received lipid-lowering agents. 244 patients (94 males, 150 females, mean age 60 years old) were susceptible to analyses. The most frequent pattern of dyslipidemia is high LDL level and high TG levels (28%). Metabolic syndrome and macrovascular complication were significant negative independent association with lipid levels within the target goals (p<0.05). Only 15.2% (19 males, 18 females) attained within the lipid tar- get goals. Patients with diabetic dyslipidemia need maximization of lipid-lowering agents, increasing the fibric acid derivatives prescription and the effort to correction of low HDL and/or high TG.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.2
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• pp.209-213
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• 2010

Anxiety and fear is two main factors that keep patients from going to dental clinic. Especially, patients may feel implants operations are more traumatic. Intravenous conscious sedation for dental treatment can make patient comfortable and relaxable. Midazolam is more popular for sedation for dental treatment, but target-controlled infusion (TCI) of propofol and remifentanil is gaining wide popularity. A 54-year-old female patient who had severe dental phobia was referred to our dental hospital. She had past history of 2 times of hyperventilation and syncope during dental treatment. The patient showed a lot of dental anxiety and fear to dental treatments and stress reduction protocol was needed. We administered intravenous conscious sedation using target controlled infusion system with remifentanil and propofol. During sedation, we monitored the status of consciousness with bispectral index and vital signs. Dental treatment could be finished successfully without any problems.

• Structural Engineering and Mechanics
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• v.22 no.2
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• pp.185-195
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• 2006

Nowadays it is very necessary to generate artificial accelerograms because of lack of adequate earthquake records and vast usage of time-history dynamic analysis to calculate responses of structures. According to the lack of natural records, the best choice is to use proper artificial earthquake records for the specified design zone. These records should be generated in a way that would contain seismic properties of a vast area and therefore could be applied as design records. The main objective of this paper is to present a new method based on wavelet theory to generate more artificial earthquake records, which are compatible with target spectrum. Wavelets are able to decompose time series to several levels that each level covers a specific range of frequencies. If an accelerogram is transformed by Fourier transform to frequency domain, then wavelets are considered as a transform in time-scale domain which frequency has been changed to scale in the recent domain. Since wavelet theory separates each signal, it is able to generate so many artificial records having the same target spectrum.