• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.685-693
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• 2007

Class I malocclusion without skeletal problem results from tooth size/arch-size discrepancies, either evidenced by crowding, or spacing problems. Treatment method can be chosen according to dentition, the amount of arch discrepancy, patient compliance, or patient demands. We report of clear aligner and spring aligner that can be applicated in cases of permanent dentition with minimal arch discrepancy in anterior segment. There are some limits of application, but these are very useful appliances in the selective case. When crowding exists, definitive analysis and diagnosis should be made before starting treatment because certain amount of space must be obtained somewhere in the dentition to resolve the crowding. Therefore, appliance should be applied when lacking space is small. Also, in cases with spacing arch circumference is reduced after alignment so no problem in intermaxilla occlusal relationship must be confirmed. In case with crowding, judicious removal of interproximal enamel is indicated.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.219-229
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• 1996

Recent construction activity of infrastructures has been booming and accelerating to incur shortage of river sand for concrete works. Thus, sea sand has been excessively used instead of river sa.nd, that directly causes to decrease the quality and the durability of concrete, and then might lead to the collapse of concrete structures. The purpose of this experimental research is not only to develop high-strength concrete using sea sand, but also to investigate mechanical properties of high-strength concrete, such as elastic moduli, compressive strength and etc, which could be used for important design data of concrete structures. Rational analytic formula for elastic moduli have been proposed together with those for the splitting tensile strength and the flexural strength, which are to be predicted from compressive strength of concrete cylinder. Optimum water-cement and water-binder ratio have been experimentally obtained so as to develop high compressive strength with and without using silica fume as a admixture for concrete. It is noted that experimental elastic moduli for high strength concrete above aCk=330kgf /cm2 are less than those by the Code. Appropriate amount of concrete mixture has been experimentally investigated so as to develop maximum compressive, flexural and splitting tensile strength.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.437-445
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• 2013

This study was conducted to develop site index equations and to estimate productive areas of Quercus acutissima by ecoprovince in Korea using environmental factors. Using the large data set from both a digital forest site map and a climatic map, a total of 48 environmental factors including 19 climatic variables were regressed on site index to develop site index equations. Four to six environmental factors for Quercus acutissima by ecoprovince were selected as independent variables in the final site index equations. The result showed that the coefficients of determination for site index equations were ranged from 0.30 to 0.41, which seem to be relatively low but good enough for the estimation of forest stand productivity. The site index equations developed in this study were also verified by three evaluation statistics such as the estimation bias of model, precision of model, and mean square error of measurement. According to the evaluation statistics, it was found that the site index equations fitted well to the test data sets with relatively low bias and variation. As a result, it was concluded that the site index equations were well capable of estimating site quality. Based on the site index equations of Quercus acutissima by ecoprovince, the productive areas by ecoprovince were estimated by applying GIS technique to the digital forest site map and climate map. In addition, the distribution of productive areas by ecoprovince was illustrated by using GIS technique.

• International Commerce and Information Review
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• v.16 no.5
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• pp.151-178
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• 2014

The objective of the present case study is to analysis how effectively Hilti, which is a former family firm owned and managed by a family in Liechtenstein as a tiny european country, a land sandwiched between Switzerland and Austria, has made a global market success. Liechtenstein has $160km^2$ land and about 36,000 residents. Despite its small size of country, however, Hilti Corporation doesn't view its location as a liability in its business strategy. Hilti is a global leading provider of professional power tools in building, mining, civil engineering etc. Also, Hilti is a firm with a clear vision to become the leading industry partner for construction professionals and building installations through customer focus, high quality equipment, and tools and systems specially designed for specific jobs. This study considered Hilti as a good case, which verifies that born-conditions, endogenous factors according to Michael Porters diamond model does not decisive role more for international competitiveness of firms. Lessons from Hilti are that in order to obtain and sustain the global competitiveness of small and medium-sized firms in Korean manufacturing sector under high production cost, they have to do actively innovative. Also they can give to customers newer and higher customer-values than competitors in abroad give. The case summarizes that the strategy of Hilti for the global market success is comprised of several factors: Technological and organizational innovation, and a clear customer-value oriented business strategy and its implementation. Innovation and its integration into marketing for the customers value creation is central to Hilti's Success. The present case study is expected to provide insights and implication for many firms in Korea that are seeking to secure global presence and market success.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.6
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• pp.110-117
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• 2011

In order to study the growth models between the growth of Sedum takevimense and growth rate in soil with three types of mix ratios, this experiment was carried out on April 3rd, 2011. A nonlinearity regression analysis was performed using the Logistic and Gompertz models by SPSS. According to the study of growth models of Sedum takevimense, the process of growth and management methods after over-wintering were explicitly determined. According to the measured values, the growth in the soil of $P_1P_2V_1$ and $P_2P_1V_1$ was better than that of $P_1$. Particularly, the average length of Sedum takevimense in the soil of $P_1P_2V_1$ was about twice as great as that in the $P_1$. The fitness test of the two growth models was: The predicted value and measured value were separately compared and analysed, the average fitting precision $R^2$ of the Logistic models was 0.995, but the average $R^2$ of the Gompertz models was below 0.978, which showed that the Logistic models were better than the Gompertz models. The growth models also showed that the growth time of Sedum takevimense was divided into three: rapid, most rapid and slow. When managed in the rapid and the most rapid time, it will grow better.

• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.51-62
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• 1992

The purpose of this paper is to estimate the ratio of under-reported business income and related tax to that which is actually reported. The business income and tax are vulnerable to being under-reported. Information about the business income and thus income tax is private information. Without information costs, the tax agency cannot collect all the information about the business income and income tax. In Korea there are more than 600,000 proprietors. Therefore, the costs to investigate the accuracy of the taxpayes' reports are substantial. The tax agency sets a level over which proprietors should report income ratio to total sales, which induces the under-report. To estimate the ratio of under-reported tax, the expenditure method is employed. By this method, the under-reported income can be easily presumed based on expenditures since expenditures are closely related to income. First, the consumption function is estimated by using cross-section data of 1986-89. Generally, the estimation results show the expected sign of the coefficients of the explanatory variables such as income, wealth, and family size. Second, the extent of under-reported business income and related tax is estimated by using the estimation results. The estimated ratios of under-reported tax and income to the actual tax and income fall in the range of 13~39% and 8~25% respectively. This estimation confirms the increasing tendency of the tax detection ratio in previous studies. However, it should be noted that this study is not based on data of the tax report but those of the urban household survey. Therefore, there still remains the possibility that the ratio of under-reported tax could be underestimated.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.69-80
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• 2001

Larix kaemferi Carr. is one of main timber species in Korea that could be found in plantations and growing stands on all over the country The proper practice of thinning is one of very important techiques in silviculture, which greatly affects the quality and size of timber produced. Proper thinning period is considered to be important for maintaining stand growth before competition initiated. To investigate suitable thinning period, this study investigates the volume and radial growths of Larix kaemferi plantation in Mt. Worak located in the central part of Korea. The main findings and conclusions obtained from this study were as follow ; (1) The tree height curve equation for Larix kaemferi in Mt. Worak was calculated H=4.25783+0.80024D(H=Tree height, D=DBH). (2) To estimate tree volume for Larix kaemferi by DBH and tree height or only by DBH, regression equations were calculated as V=0.00147-0.002095D-0.000211H+0.00015D.H++$0.000744D^2$+$0.000008H^2$(V=Volume(($m^3$), H=Tree height(m), D=DBH(cm)), V=0.0000794-0.000512D+$0.000826D^2$. (3) The criteria of estimating thinning time of Larix kaemferi are the age when maximum tree height-MAI(mean annual increment) obtained and the age when annual DBH increments of dead trees decrease to below average. (4) The age of maximum tree height MAI was not significantly correlated with stocking. Therefore, it can not be used as a criterion for estimating thinning time of Larix kaemferi (5) The estimated thinning time equation of Larix kaemferi was obtained by regression analysis of the disk section collected from dead trees. The obtained equation is Y=0.2825+0.01752X(Y=Desirable thinning age, X=the sum total of nearest 4-trees interval(cm)). (6) General estimated thinning age of Larix kaemferi, which planted 3,086 stocks/ha, is concluded as 12 to 14 year.

• Spatial Information Research
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• v.21 no.2
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• pp.23-33
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• 2013

W ith the recent advancement of IoT (Internet of Things) technology, there has been much interest in the spatial query processing which energy-efficiently acquires sensor readings from sensor nodes inside specified geographical area of interests. Therefore, various kinds of spatial query processing algorithms and distributed spatial indexing methods have been proposed. They can minimize energy consumption of sensor nodes by reducing wireless communication among them using in-network spatial filtering technology. However, they cannot optimize multiple spatial queries which w ill be w idely used in IoT, because most of them have focused on a single spatial query optimization. Therefore, we propose a new multiple spatial query optimization algorithm which can energy-efficiently process multiple spatial queries in a sensor network. The algorithm uses a concept of 'query merging' that performs the merged set after merging multiple spatial queries located at adjacent area. Here, our algorithm makes a decision on which is better between the merged and the separate execution of queries. For such the decision making, we additionally propose the cost estimation method on the spatial query execution. Finally, we analyze and clarify our algorithm's distinguished features using the spatial indexing methods of GR-tree, SPIX, CPS.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.327-334
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• 2017

The purpose of this study was to compare the personality types between pediatric and other dental residents. 77 pediatric dental residents and 71 other dental residents in Korea were surveyed by Myers-Briggs Type Indicator questionnaire. Myers-Briggs Type Indicator (MBTI) had 4 personality dichotomies consisting of 2 opposite characteristics that were extraversion / introversion, sensing / intuition, thinking / feeling, and judging / perception. Combinations of these four dichotomies could make 16 personality types. The percentage of pediatric dental residents was higher in sensing and judging, but there were no statistically differences. The majority of personal type was ISTJ in both groups. Statistical significance observed only in gender. The ratio of thinking was higher in male than in female (p < 0.05). The meaning of this study was the first survey performed on the personality types between pediatric dental residents and other dental residents in Korea. Further study with pre-survey orientation and increased sample size should proceed.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.266-272
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• 2009

This study was conducted survey on fruit and vegetables farms (FM), consulting companies (CC), and the consultants (CT) to investigation actual conditions and improvements in consulting part of horticulture. In results of survey on FM, FM chose 'necessity' on consulting for learning of production skill and 'field visit' in means of consulting. FM had a low trust on experience and knowledge of CT and answered that FM had not enough time for consulting by reason of over-work of CT, chose 'necessity' on crop registration system. In results of common questions among FM, CC, and CT, same answer of questions were term of contract (answer: yearly contract), means of consulting (answer: visit), consulting time per a visit (answer: $2{\sim}3$hours). Different answer between supplier (CC, CT) and consumer of consulting were decision method of contract price (answer: provisional contract$\neq$contents and the quality of consulting), percentage of government subsidy (answer: propriety$\neq$step-up).