• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.404-404
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• 1996

In order to ensure a concrete expansion anchor is suitable for a given application, the load resistance behavior of the anchor must be known. ASTM E488 provides a standard method of testing expansion anchors for static and dynamic loads. Due to the many types of anchors available commercially and the large variability of applications, the ASTM does not delineate all details or requirements necessary to comprehensively determine the dynamic load behavior of concrete expansion anchors. A test program is presented in this paper which was developed and implemented to determine the cyclic load behavior of wedge-type concrete expansion anchors. Test results are also presented along with a discussion of the behavior of anchors, and their suitability for use.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.327-346
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• 1996

The purpose of this study was to evaluate the shear bond strengths, microhardness, compressive strength and contraction gap at the resin-tooth interface of two types of composite resins polymerized with visible light and argon laser sourse. The results from the present study can be summarized as follows ; 1. Resin samples polymerized either by argon laser or visible light did not show significant difference in their physical properties tested(p>.05). 2. The contraction gap at the resin tooth interface was found to be present in all samples but any significant difference between groups could not be established due to their variability. Although the superiority of argon laser over visible light in enhancing the physical properties of resin could not be elucidated in the present study, continous efforts are deemed to be worthwhile to investigate this area using different conditions and materials of experiment.

• Korean Journal of Child Studies
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• v.27 no.6
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• pp.217-234
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• 2006

This study examined variability of gestures and their correlation with vocabulary acquisition in the communication of infants. Subjects were 96 infants, 7 to 24 months of age, residing in Seoul and its vicinity. Instruments were the Communication and Symbolic Behavior Scales (Iverson, et al., 1999) and the MacAuther Communicative Development Inventory-Korean (Bae and Lim, 2002). Data were analyzed by one-way ANOVA and Pearson's Correlation. Results identified monthly changes in types of communicative gesture used by infants: more deictic at younger and more representational at older ages. Deictic gestures were related to size of the receptive vocabulary and size of the whole vocabulary. Representational gestures were related to acquisition of expressive vocabulary, size of the receptive, and size of the whole vocabulary.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.961-968
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• 2002

This paper proposes a new access method which is to considered the high variability in World Wide Web and manage the web cache space. Instead of using a single cache, we divide a cache and store all documents according to their file types. Proposed method was compares with current cache management policies using LFU, LRU and SIZE base algorithm. Using two different workload, we show the improvement hitting ratio and byte hitting ratio through simulating on the file type caching.

• Communications for Statistical Applications and Methods
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• v.28 no.2
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• pp.171-188
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• 2021

Due to an increased demand for longevity risk analysis, various stochastic models have been suggested to evaluate uncertainly in estimated life expectancy and the associated value of future annuity payments. Recently updated data allow us to analyze mortality for a longer historical period and extended age ranges. This study followed up previous case studies using up-to-date empirical data on Korean mortality and the recently developed R package StMoMo for stochastic mortality models analysis. The suitability of stochastic mortality models, focusing on retirement ages, was investigated with goodness-of-fit, validity of models, and ability of generating reasonable sets of simulation paths of future mortality. Comparisons were made across various types of models. Based on the selected models, the variability of important estimated measures associated with pension, annuity, and reverse mortgage were quantified using simulations.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.67-73
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• 2009

Soil $CO_2$ efflux can vary markedly in magnitude over both time and space, and understanding this variation is crucial for the correct measurement of $CO_2$ efflux in ecological studies. Although considerable research has quantified temporal variability in this flux, comparatively little effort has focused on its spatial variability. To account for spatial heterogeneity, we must be able to determine the number of sampling points required to adequately estimate soil $CO_2$ efflux in a target ecosystem. In this paper, we report the results of a study of the number of sampling points required for estimating soil $CO_2$ efflux using a closed-dynamic chamber in young and old Japanese cedar plantations in central Japan. The spatial heterogeneity in soil $CO_2$ efflux was significantly higher in the mature plantation than in the young stand. In the young plantation, 95% of samples of 9 randomly-chosen flux measurements from a population of 16 measurements made using 72-$cm^2$ chambers produced flux estimates within 20% of the full-population mean. In the mature plantation, 20 sampling points are required to achieve means within $\pm$ 20% of the full-population mean (15 measurements) for 95% of the sample dates. Variation in soil temperature and moisture could not explain the observed spatial variation in soil $CO_2$ efflux, even though both parameters are a good predictor of temporal variation in $CO_2$ efflux. Our results and those of previous studies suggest that, on average, approximately 46 sampling points are required to estimate the mean and variance of soil $CO_2$ flux in temperate and boreal forests to a precision of $\pm$ 10% at the 95% confidence level, and 12 points are required to achieve a precision of $\pm$ 20%.

• Imaging Science in Dentistry
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• v.44 no.3
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• pp.221-227
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• 2014

Purpose: This study aimed to investigate the clinical anatomy of lower premolar roots in a Spanish population by using cone-beam computed tomography (CBCT), correlating findings with patient gender and tooth type. Materials and Methods: Using 70 CBCT images, we evaluated 126 healthy, untreated, well-developed lower premolars. The number and morphology of roots and root canals, and the foramina number were assessed. Results for gender and tooth type were compared using the chi-squared and ANOVA tests. Results: The average length of teeth and roots was significantly higher in men (p=0.00). All 126 premolars had a single root. One canal was found in 83.3% of the premolars, with no gender or tooth type differences; Vertucci configuration types I and V were the most prevalent. The first premolars showed significantly greater variability than the second premolars (p=0.03). A single apical foramen was found in 89.7% of the premolars, with no differences by tooth type. Women had a significantly higher prevalence of two apical foramina than men (p=0.04). Some degree of curvature was observed in 65% of the premolars, with no differences by gender or tooth type. A root angle of more than $20^{\circ}$ was found in 12.98% of the premolars, without any differences by gender or tooth. Conclusion: All premolars were single-rooted. One canal had the most prevalent morphology. More variability in canal anatomy was found in the first premolars. Curvatures greater than $20^{\circ}$ were found at less than 5 mm from the apex.

• Journal of KIISE:Software and Applications
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• v.35 no.3
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• pp.137-148
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• 2008

Services system which has been emerging as a new way of application development utilizes services as fundamental units for developing a system. Services system can offer services within web environment as well as the ubiquitous environment where mobile devices are connected to wired or wireless network. In order to provide the functionality that meets users' requirements, the most appropriate service should be selected among candidate services by taking requests and context information into account. Therefore, it is important that the service system should provide services to users by dynamically adapting to users' requirements and context information. Since different users request same functionality with different context information, one service can be differently offered to users so that variability can happen to the service systems. Most researches on context-aware systems have a tendency to solve dynamic adaptation by using more or less ad hoc manner In this paper, we consider various types of services which are performed according to context information as variability and propose adaptable architecture by applying concepts of product line architecture in order to deal with variabilities systematically.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.903-909
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• 2004

The variability of mtDNA hypervariable segment I (HVS I) sequences was investigated in a total of 48 birds belonging to 12 Chinese native chicken breeds. Sixteen haplotypes were identified from 35 polymorphic nucleotide sites which accounted for 6.4% of a sequenced 544 bp fragment. Diversity analysis of the haplotypes showed that Tibetan, Langshan and Henan cockfight chicken had only one haplotype, while ancient haplotypes existed in Taihe silky and Chahua chicken. Phylogenetic analysis of the haplotypes suggested that Chinese native chicken breeds shared 5 maternal lineages and some breeds would share the same maternal lineage, regardless of their external features and ecological types. Both divergent and phylogenetic analysis of the haplotypes indicated the close genetic relationships between the Chinese native chicken breeds and G. g. gallus and G. g. spadiceus from different areas, which implied that G. g. gallus and G. g. spadiceus were the original ancestors of the Chinese native chicken breeds.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.136-144
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• 2010

Since most domestic apartment, built in bearing wall system limiting variability of space, in spite of its good durability, cannot accept life style change and is being wasted, dumped scraps of which cause environmental pollution and waste of resources. As a response for this, researches on sustainable housing, that is, 'long-life housing' which has high durability, and variability responding life style change of the resident are in progress in and out of country. Therefore, this article aims, in suggesting the various status appearing on apartment and the interior plan responding the problem, to research on the house plan in the future which can be used continuously instead consuming type of apartment shortly used and discarded with understanding of long-life housing developed in foreign countries, and grasping the factors of application plan. Various reports from previous researches were comparatively analyzed and the studies on the characteristics, the real examples and the types of the surfaces were performed on the experimental model of long-life housing and similar residential surfaces to find the concept to be applied to Long-Life Housing and the introduction method of such concept. This article tries not only to prevent 'scarp and build', the serious cause of environmental pollution, but also to be basic materials for interior construction plan afterwards through 'long-life housing interior design plan' as the new conception which can accept life style and life cycle change.