• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.255-270
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• 2005

Memory for repeated items is better if they are repeated in a spaced than in a massed fashion (Sparing effect). To investigate the neural mechanisms of sparing effect and successful encoding, lags of repetition were manipulated at encoding stage in an event-related MU study. The behavioral data showed typical spacing effect on recognition judgment, and greater activity for items that were repeated in a spaced fashion than for items that were repeated in a massed fashion has been observed in dorsolateral frontal cortex(DLFC) and ventrolateral frontal cortex(VLFC) of left hemisphere. These conical regions also showed greater activity for novel items than for items that were repeated in a massed fashion. These findings suggest that sparing effect and its relevant successful encoding are attributed to higher level of attentional control and semantic processing.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1083-1090
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• 2016

In clinical studies, different types of outcomes (e.g. repeated measures data and time-to-event data) for the same subject tend to be observed, and these data can be correlated. For example, a response variable of interest can be measured repeatedly over time on the same subject and at the same time, an event time representing a terminating event is also obtained. Joint modelling using a shared random effect is useful for analyzing these data. Inferences based on marginal likelihood may involve the evaluation of analytically intractable integrations over the random-effect distributions. In this paper we propose a joint HGLM approach for analyzing such outcomes using the HGLM (hierarchical generalized linear model) method based on h-likelihood (i.e. hierarchical likelihood), which avoids these integration itself. The proposed method has been demonstrated using various numerical studies.

• Communications for Statistical Applications and Methods
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• v.17 no.2
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• pp.231-239
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• 2010

In vaccine research, proportional hazards model including only first event have been widely used for estimating vaccine efficacy because it is easy to interpret and convenient. However, this method causes not only loss of information but also biased result when heterogeneity of study subject in exposure and susceptibility exists. Furthermore, it is hard to ignore the possibility that each event is correlated with each other in the repeated events. Therefore, we compare various statistical models to estimate vaccine efficacy under various situations with heterogeneity and event dependency.

• Korean Journal of Cognitive Science
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• v.11 no.3_4
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• pp.83-93
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• 2000

The effect of immediate and delayed recognition memory on event-related potential (ERP) was studied using a continuous recognition memory task and event-related potential (ERP). Among 240 stimulus words 40 words were not repeated. 100 were immediately repeated and 100 were repeated after 5 intervening words. All words presented only once during the experiment were referred to as new words. Subjects responded faster and more accurately to words repeated immediately than to new words a and to those repeated after intervening words. In terms of ERP results the immediately repeated words were associated with large P300 amplitude, early P300 latency and a absence of N400. while words repeated after a delay were associated with small P300 a amplitude. late P300 latency and the presence of N400. N400 was elicited only to new w words and to those repeated after a delay. The general morphology of the waveform was s similar for three stimulus-presentation conditions until around 3l0ms after the onset of stimulus. These results indicate that immediate and delayed recognition memory could be dissociated into two distinct processes possibly being mediated by different cerebral mechanism, and the dissociation between two types of recognition memory emerges around 3l0ms poststim'ulus. The immediate and delayed recognition memory for words are considered in terms of template matching and memory searching.

• Korean Journal of Computational Design and Engineering
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• v.19 no.1
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• pp.29-40
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• 2014

Conceptual Modeling is the process of abstracting a model from a real or proposed system. It is probably the most important aspect of a simulation study. Relate works show that the elementary developers devoted little time to understanding how the systems actually worked, namely they didn't build appropriate conceptual model. Thus, the result of simulation is inconsistent because it depends on developer's competence. Although many researchers suggested various techniques enabling developer to build conceptual model, there were several limitations. In this study, to overcome the limitations of existing techniques, we proposed COMBINE-DES (COnceptual Model BuildINg framEwork using ontology for Discrete Event Simulation). The COM-BINE-DES supports expediting the conceptual modeling with Solution ontology generated by Domain ontology and Simulation ontology. Moreover, it provides consistent simulation result regardless of repeated modeling.

• Communications for Statistical Applications and Methods
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• v.20 no.4
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• pp.283-290
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• 2013

Subjects can experience two types of recurrent events in a longitudinal study. In addition, there may exist intermittent dropouts that results in repeated observation gaps during which no recurrent events are observed. Therefore, theses periods are regarded as non-risk status. In this paper, we consider a special case where information on the observation gap is incomplete, that is, the termination time of observation gap is not available while the starting time is known. For a statistical inference, incomplete termination time is incorporated in terms of interval-censored data and estimated with two approaches. A shared frailty effect is also employed for the association between two recurrent events. An EM algorithm is applied to recover unknown termination times as well as frailty effect. We apply the suggested method to young drivers' convictions data with several suspensions.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.73-80
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• 2014

In this paper, we propose an incremental simulation method in event-driven HDL simulation to reduce the simulation execution time. In general, the simulation is repeated with a series of design changes. Incremental simulation is an efficient simulation method that shortens the simulation execution time for the following simulation by using the result of previous simulation. We have observed the effectiveness of the proposed approach through the experimentation with multiple real designs.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1117-1125
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• 2014

In a longitudinal study, subjects can experience same type of events repeatedly. Also, there may exist intermittent dropouts resulting in repeated observation gaps during which no recurrent events are observed. Furthermore, when such observation gaps have incomplete forms caused by the unknown termination times of observation gaps, ordinary approaches result in biased estimates. In this study, we investigate the effect of ignoring observation gaps and propose methods to overcome this problem. For estimating the distribution of unknown termination times, an interval-censored mechanism is applied and two cases are considered. Simulation studies are carried out to evaluate the performance of the proposed method. Conviction data of young drivers with several suspensions are analyzed to illustrate the suggested approach.

• Journal of the Korean Home Economics Association
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• v.49 no.2
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• pp.37-49
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• 2011

The present study investigated the semantic and syntactic processes in Korean children's sentence comprehension by measuring event-related brain potentials(ERPs). The subjects were 18 right-handed, healthy native Korean children(1st graders), who were free from any hearing problems. While the children listened to the auditory sentence stimuli, ERPs were recorded with the electrodes mounted in a 'Quik-Cap' on the subject's head. The ERP data were recorded and analyzed using the NeuroScan 4.3 and EEGLABv6.03b programs. For statistical analyses, descriptive statistics, three-way repeated measures ANOVA, and t-tests were performed using a SPSS 15.0 PC program. The results indicated that semantic violations elicited a negativity (N400) ranging from 300 to 500 msec. For syntactic violations, children displayed a positivity (P600) ranging from 900 to 1,100 msec. The discovery of N400 and P600 in semantic and syntactic processes respectively, confirmed the suggestion that Indo-European and Korean languages share a common mechanism for sentence comprehension.

• The Journal of Internal Korean Medicine
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• v.40 no.1
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• pp.154-163
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• 2019

Objective: We report on the administration progression and adverse event of Er-Xian decoction for menopausal hot flushes. A hot flush is a rapid and intense heat-dissipation reaction that involves considerable sweating, enlargement of the peripheral blood vessels, and internal body heat. Er-Xian decoction is a prescription for treating menopausal hot flush symptoms in postmenopausal women. We report administration progression and adverse event of Er-Xian decoction for menopausal hot flush. Methods: We used the Menopause Rating Scale and Menopause-Specific Quality of Life questionnaire to evaluate the progression of hot flushes, and we conducted a literature review to determine the effective dosage of Er-Xian decoction. Result: In all cases, Facial hot flushes and evaluation variables were improved by the administration of EXD. However, in Case 1, a rise of liver function indexes which may be related to EXD administration was observed. Conclusion: Considering that menopausal flushing usually lasts for several years, The resluts are meaningful that the short-term administration of EXD led to improvement of symptoms. In order to further use EXD in the future, it will be necessary to conduct follow-up studies on the subject of safety verification, such as repeated dose toxicity studies.