• Korean Management Science Review
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• v.20 no.1
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• pp.37-49
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• 2003

There is an increasing need to use mobile Internet as a research tool as wireless technology has been developing rapidly. However, little research has been conducted to confirm methodological validity of mobile Internet survey. This study examines the possibility of using mobile Internet as a survey tool by comparing survey results of mobile and stationary Internet surveys with the same questionnaire. The results were analyzed from both economic and theoretical perspectives. Both mobile and stationary Internet survey sites were implemented with supports from domestic mobile and stationary Internet portals and telecommunication companies. The results show that there exist several differences between two survey methods. First, many respondents who use mobile Internet gave up at the early stage. However, once people continued to respond, they answered the questions to the end. Second, means and standard deviations of mobile internet respondents were higher than that of stationary Internet. Third, the results of two survey methods were significantly different by comparing construct validity that includes both discriminant validity and convergent validity. Finally, this paper ends with implications and limitations of using mobile Internet as a survey tool.

• Journal of Korean Society for Quality Management
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• v.22 no.1
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• pp.169-178
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• 1994

Nonparametric tests for comparing two treatments when data are subject to unequal patterns of censorship are discussed. Best precedence test proposed by Slud can be viewed as a nice alternative test comparing with weighted log-rank tests, not to mention the advantage of short experimental period. This research revises some missing parts of Slud's test and examines the asymptotic power of it under the nonproportional hazard alternatives through the simulation. The simulation studies show best precedence test has reasonable power in the sense of robustness under nonproportional hazard alternatives and could be recommended at such situation.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.767-778
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• 2008

Comparison between two or more fuzzy numbers, along with their ranking, is an important subject discussed in scholarly articles. We endeavor in this paper to present a simple yet effective parametric method for comparing fuzzy numbers. This method offer significant advantages over similar methods, in comparing intersected fuzzy numbers, rendering the comparison between fuzzy numbers possible in different decision levels. In the process, each fuzzy number will be given a parametric value in terms of $\alpha$, which is dependent on the related $\alpha$-cuts. We have compared this method to Cheng's centroid point method [5] (The relation of calculating centroid point of a fuzzy number was corrected later on by Wang [12]). The proposed method can be utilized for all types of fuzzy numbers whether normal, abnormal or negative.

• Journal of computational fluids engineering
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• v.3 no.1
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• pp.30-36
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• 1998

The three dimensional Navier-Stokes equations in rotational coordinate are solved using a multigrid algorithm for the calculations of turbulent flows in centrifugal compressor impellers. Some numerical studies are made in applying the multigrid algorithm for the turbulent flow calculations with the standard κ-ε equations. The present method is used to calculate the flow fields of Mizuki's B-type and Niigata Ms. 350 centrifugal compressor impellers. Fast convergent steady-state solutions are carefully examined, comparing the static pressure distributions along the impeller flow passage and also in the diffuser with experimental data. Performance of a centrifugal compressor system is also numerically validated by comparing the performances of the impeller and the diffuser individually.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.3
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• pp.105-124
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• 2009

Data Envelopment Analysis (DEA) is a methodology of computing the relative efficiency of each decision making unit (DMU) by comparing it with other DMUs having similar input and output structure. In this paper, we compare the efficiency of Korean rail transit corporations using DEA. To do this, we design a DEA-AR/AHP model, and evaluate efficiency by comparing the subway operating agencies of six big cities. The analysis reveals that Seoul Metro and Seoul city railroad construction turn out to be the most efficient groups. The result of this research can provide helpful information for effective management in a domestic subway operating agency.

• Korean Institute of Interior Design Journal
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• v.14 no.5 s.52
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• pp.193-204
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• 2005

Design took a radical turn in the 1980's, deconstructing the rigid ideology of the Modernism, often with great humor. Contemporary representable Avant-garde designers, Philippe Starck and Ron Arad brazenly borrowed from the 'historical elements' of previous styles and created bio-morphic forms with whimsical names of furniture. This study is proposed to understand the diversity of contemporary design, by comparing these two furniture designers. It also covers the common factors in contemporary furniture design, and analyzes their individual differences and similarities in design. It helps to plan the foundation of design methods for 21C, and predict and respond to the future as a reference point. Philippe Starck links Romantic Rationalism within Minimal style and Ron Arad links Deconstructivism within High-tech style but both of them pursue of Organic concept design in their furniture through the concept of humanism. They are able to establish a base of contemporary furniture design by adapting new conceptual form, and design process for the general public.

• Journal of Institute of Convergence Technology
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• v.7 no.1
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• pp.23-29
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• 2017

A pterosarus is an ancient flying reptile and the first vertebrate with powered flight. The shapes of the pretosarus'airfoil in the published literature are reconstructed. The aerodynamics of the Pterosarus is obtained using a free software XFOIL. The steady aerodynamics of the Pterosarus' airfoil are investigated focusing on the gliding performance. The numerical results are validated by comparing the computed aerodynamic coefficients with the measured data. The secretes of the Pterosarus' highly camberred airfoil are elucidated by comparing the aerodynamics with that of the birds'.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.51
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• pp.79-99
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• 2011

This study describes the seller's duty to deliver the goods in conformity with the contract. The purpose of this study is twofold: to analyze the seller's principal duty, comparing the United Nations Convention on the International Sale of Goods(CISG) with Sale of Goods Act(SGA) and to provide legal and practical advice to contracting parties who consider CISG or SGA as a governing law. This paper first considers the requirements for the conformity with the contract, which means contractual requirements agreed between parties and implied requirements not agreed between parties. Following this, the exclusion of the seller's duty to deliver the goods required by the contract is described. Finally, this paper ends up giving contracting parties legal and practical advice.

• International Journal of Contents
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• v.12 no.1
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• pp.54-59
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• 2016

The purpose of this paper is to discover how the use of digital applications can affect students' attitudes toward positive classroom participation and performance in learning a foreign language. Participants of this study were 128 students who took a foreign language class at a high school in central Korea. To find out students' perceptions and attitudes toward the effect of using a digital application for their foreign language study, online questionnaire and focus-group interview were conducted. Our research findings revealed that these students could engage in active language learning and experience learning improvement while studying a foreign language with digital applications. The improvement was possible by creating more interactive activities and quizzes. In addition, the digital application provided students immediate feedback. It gave students and teachers various motivations beyond the traditional 'chalk and talk' format of text-only-classes. This study provides an overview of the usefulness of digital application. In addition, it provides understanding for students' perceptions and involvement using digital application in a foreign language classroom.

• Journal of Distribution Science
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• v.10 no.12
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• pp.19-24
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• 2012

Purpose - This paper discusses the heterogeneous fixed fleet vehicle routing problem with pick-up and delivery (HFFVRPPD), for vehicles with different capacities, fixed costs, and travel costs. Research Design, data, methodology - This paper made nine assumptions for establishing a mathematical model to describe HFFVRPPD. It established a practical mathematical model, and because of the non-deterministic polynomial-time hard (NP-hard), improved the traditional simulated annealing algorithm and tested a new algorithm using a certain scale model. Result - We calculated the minimum cost of the heterogeneous fixed fleet vehicle routing problem (HFFVRP) with a single task and, on comparing the results with the actual HFFVRP for the single task alone, observed that the total cost of HFFVRPPD reduced significantly by 46.7%. The results showed that the new algorithm provides better solutions and stability. Conclusions - This paper, by comparing the HFFVRP and HFFVRPPD results, highlights certain advantages of using HFFVRPPD in physical distribution enterprises, such as saving distribution vehicles, reducing logistics cost, and raising economic benefits.