• Research in Mathematical Education
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• v.10 no.3 s.27
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• pp.169-187
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• 2006

Ubiquitous errors in algebra like $(x+y)^2=x^2+y^2$ are a constant reminder that most students' manipulation of algebraic symbols has become detached from structural principles. The U.S. mathematics education community (NCTM, 2000) has responded by shying away from algebra as a structural study, preferring instead to ground meaning in empirical domains of reference. A new analysis of such errors shows that students' detachment from structural meaning stems from an inadequate structural curriculum, not from the inherent difficulty of adopting an abstract perspective on expressions and equations. A structural curriculum is outlined that preserves the possibility of students' engaging fully with algebra as both an empirical and a structural study.

• Journal of the Korean Data and Information Science Society
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• v.16 no.1
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• pp.79-94
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• 2005

This study examines which factors affect on Job-Satisfaction of Tour Guide in Korea, perceiving that Job-Satisfaction of Tour Guide affects customer satisfaction, and outcomes of business. In the tourism industry, Tour Guides are one of the most important factors influencing customer satisfaction, because they are one of the key front- line players. Ultimately, the purpose of this study is to present the importance of efficient management for human resources through investigating Job-Satisfaction of Tour Guide. To active purpose of this study, both literatures and empirical research based on Japanese, and Chinese Tour Guides in Korea were adopted and conducted. In conclusion, in order to improve psychological and behavioral outcomes of the Tour Guides, job satisfaction factors have to be improved in many ways and also travel managers should consider them.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1199-1215
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• 2011

Relaxing an unrealistic assumption of a representative percolation model, this paper demonstrates that herd behavior leads to a high increase in volatility but not trading volume, in contrast with information flows that give rise to increases in both volatility and trading volume. Although detecting herd behavior has posed a great challenge due to its empirical difficulty, this paper proposes a new methodology for detecting trading days with herding. Furthermore, this paper suggests a herd-behavior-stochastic-volatility model, which accounts for herding in financial markets. Strong evidence in favor of the model specification over the standard stochastic volatility model is based on empirical application with high frequency data in the Korean equity market, strongly supporting the intuition that herd behavior causes excess volatility. In addition, this research indicates that strong persistence in volatility, which is a prevalent feature in financial markets, is likely attributed to herd behavior rather than news.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.126-132
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• 2002

By using the reference data, the empirical equations which describe the interrelationships of explosion properties and physical properties of n-chlorinated hydrocarbons have been derived. The properties which have been correlated are the lower and upper explosive limits, the stoichiometric coefficients, the heats of combustion, the carbon numbers. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosive limits(LEL) of chlorinated hydrocarbons on the basis of the literature data are proposed. The fire and explosion properties calculated by the proposed equations in this research were a good agrement with literature data within a few A.A.P.E.(Average Absolute Percent Error) and A.A.D.(Average Absolute Deviation.) From a given explosive properties, by using the proposed equations, it is possible to predict to the fire and explosion characteristics for the other chlorinated hydrocarbons.

• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.77-88
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• 1999

Container terminal productivity is a critical factor for both the terminal operator and liner companies. For the former it is a determinant factor of the competitiveness and profit of terminal, and for the later it is one that determines ships' tern round time and hence ships' operation costs. The concept and measures of productivity are however not well defined and unified throughout terminals in the world. This paper therefore deals with the empirical study on the evaluation of container terminal productivity. It first clarifies the concept of terminal productivity, and secondly based on the actual data on container terminals in and outside Korea, productivity is evaluated and compared. Finally, problems hampered efficient operation of Korean terminals are derived, and several comments are suggested for solving them.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.387-388
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• 2006

The influence of porosity (P) on Young's modulus (E) and Poisson's ratio $(\upsilon)$ of sintered steels produced from four types of steel powders was investigated. The values of E and $(\upsilon)$ depend mainly on the value of P, and those were a little affected by alloying elements. The relationships between E, $(\upsilon)$, and P were described as following equations: $E\;=\;E_0{\cdot}(1\;-\;k_E{\cdot}P)^2$ and $\upsilon\;=\;({\upsilon}_0\;-\;\upsilon_{sub}){\cdot}(1\;-\;k_{\upsilon}{\cdot}P)2+\upsilon_{sub}$, where subscript 0 means P = 0, and $k_E,\;k_{\upsilon}$ and ${\upsilon}_{sub}$ are empirical constants. These approximate equations showed good agreement with empirical results.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.73-97
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• 2009

The IT implementation literature suggests that various implementation factors play critical roles in the success of an information system; however, there is little empirical research about the implementation of data warehousing systems has unique characteristics that may impact the importance of factors that apply to it. In this study, a cross-sectional survey investigated a model of data warehousing success. Data warehousing managers and data suppliers from 51 organizations completed paired mail questionnaires on implementation factors and the success of the warehouse. The purpose of this study is to identify which factors have a positive impact on the successful implementation of DW among organizational implementation success, project implementation success, and technical implementation success which are selected as implementation factors of DW. To do so, this study comprehensively analyze the previous studies on the success factors of the information system and DW to develop the study model and set the hypothesized. Then, it verified the hypothesis via the empirical analysis after collecting the materials through the survey. Finally, the discussion of the study's results, offered the implications of the findings, and the conclusions of the findings followed.

• Journal of the Korean Institute of Navigation
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• v.18 no.4
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• pp.59-81
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• 1994

Korean property and liability insurance companies have underwrited hull insurance without proper undrewriting ability. But after April 1996. in case of Korean insurance market being opened the companies have to make hull insurance rate by themselves. Accordingly, in this study, the writer embodies important factors in making hull insurance rate by an empirical survey. In empirical survey, the writer used a questionnaire, 74 proper data was obtained from 96 officers working in making hull insurance rate in 12 Korean property and liablity insurance companies and 24 the foreign companies at home. Reliability was tested by Cronbach's Alpha and a conceptual validity by Factor Analysis. Hypothesis estabilished in this study was tested by Correlation and Multiple Regression Analysis. Results of testing hypothesis are as follows: Firstly, the traits of insurer and the assured influence significantly(P<0.05) on making hull insurance rate. Secondly, expected loss ratio, ship manager, ship's age, insured amount, level of the cost of repairing and salvage, shipowner, period of insurance, level of overseas rating, profit and expense, trading limits, ship's classification, conditions of insurance, and ship's size influence significantly(P<0.05) on making hull insurance rate.

• Asia pacific journal of information systems
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• v.15 no.3
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• pp.1-7
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• 2005

This paper examines strategic competition model between offline and online retailers and draws strategic implications. Research on the price competition between conventional offline retailers and online retailers has been done through empirical approaches, however, the results are conflicting. This paper reconciles the existing conflicting empirical findings on price levels between offline and online retailers through theoretical approach. This paper analyzes how the internet market has effect on equilibrium prices of both offline and online retailers and discusses the possible reasons why there exist price differences between offline and online retailers in business to consumer electronic commerce.

• Journal of Gifted/Talented Education
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• v.12 no.2
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• pp.59-69
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• 2002

A 4-year joint research project(1999-2003), entitled "The Development of Multiple Talents(DMT)", has been designed and carrying out under the sponsorship of the National Science Council, R.O.C. (Taiwan). A 3-dimension construct is proposed for the DMT: form of talents (10 forms, mainly based on Gardner's theory of multiple intelligences), function of talents (3 functions, based on Sternberg's conception of successfulintelligence), and developmental stage (4 stages, from pre-school to senior high). To take an example of its empirical studies, Wu and Chien (2000), based on a renovated conception of personal intelligence, developed the "Personal Intelligence Inventory" (PII). By means of the PII, it was found that there were some personal intelligence differences between gifted and regular pupils; however, gifted group was not as superior as on academic performance to the regular one (Wu & Chien, 2000). It was also found that there were significant relationships between pupils' personal intelligence and school adjustment in both groups (Tsai & Wu, 2000).