• Title/Summary/Keyword: empirical modeling

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Study on Evaluation of Effective Thermal Conductivity of Unsaturated Soil Using Average Capillary Pressure and Network Model (평균 모세관압과 네트워크 모델을 이용한 불포화토의 유효 열전도도 산정에 관한 연구)

  • Han, Eunseon;Lee, Chulho;Choi, Hyun-Jun;Choi, Hangseok
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.93-107
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    • 2013
  • Thermal conduction of the particulate composites or granular materials can be widely used in porous materials and geotechnical engineering. And it has continued to develop "effective thermal conductivity" of medium by modeling energy relationship among particles in medium. This study focuses on the development of the effective thermal conductivity at the unsaturated conditions of soils using the modified network model approach assisted by synthetic 3D random packed systems (DEM method, Discrete Element Method) at the particle scale. To verify the network model, three kinds of glass beads and the Jumunjin sand are used to obtain experimental values at various unsaturated conditions. The PPE (Pressure Plate Extractor) test is then performed to obtain SWCC (Soil-Water Characteristic Curve) of soil samples. In the modified network model, SWCC is used to adjust the equivalent radius of thermal cylinder at contact area between particles. And cutoff range parameter to define the effective zone is also adjusted according to the SWCC at given conditions. From a series of laboratory tests and the proposed network model, the modified network model which adopts a SWCC shows a good agreement in modeling thermal conductivity of granular soils at given conditions. And an empirical correlation between the fraction of the mean radius (${\chi}$) and thermal conductivity at given saturated condition is provided, which can be used to expect thermal conductivity of the granular soils, to estimate thermal conductivity of granular soils.

The Effect Strategic Alliances on the Performance in Container Liner Shipping Companies (컨테이너 정기선사의 전략적 제휴 특성이 재무적 성과와 비재무적 성과에 미치는 영향)

  • Lim, Jong-Sub
    • Journal of Distribution Science
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    • v.14 no.6
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    • pp.99-106
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    • 2016
  • Purpose - The antecedent to the relationship between the effect of the characteristics of strategic alliances and the performance of container liner shipping companies has been investigated in this study as container liner shipping companies' strategic alliances. It affects positively and negatively home, partner, and the third parties' performance in container liner shipping companies. Extensive literature reviews on shipper's strategic alliances reveal that strategic alliances in financial and non-financial performance of container liner shipping companies show the performance such as economic effects, business performance, global supply chain management performance, customer satisfaction, and forward integration and backward integration performance. The purpose of this study is to test empirically that the relationship between the characteristics of strategic alliances and financial and non-financial performance in container liner shipping companies. Structured equation modeling and confirmatory factor analysis were used to test the hypothesis using AMOS statistics program. Most previous researches focused on the relationship between the characteristics of strategic alliances and alliance types. There are few empirical studies that focus on business performance data because it is difficult to collect data in container liner shipping companies. However, this research measures financial and non-financial performance differently compared with the previous researches focusing on the characteristics of strategic alliances and alliance types measurements. Research design, data, and methodology - The conceptual model for the study is based on the studies of Lim (2010), Chen & Zhen (2009), and Wang & Meng (2014). The model is built around the factors of characteristics of strategic alliances and business performance. Cost, marketing, and service factors are regarded as proxy for the characteristics of strategic alliances. The financial and non-financial performance are regarded as proxy for the performance of strategic alliances. Based on the analysis of one hundred cases such as forwarder, shipper, and liner shipping companies, this study uses structural equation modeling to verify the effects of the characteristics of strategic alliances on business performance. Conclusions - This study provides container liner shipping companies to get some policy and practical implications in terms of the characteristics of strategic alliances and business performance. First, the cost factor for alliances characteristics has a positively significant influence on the financial and non-financial performance of strategic alliances. The cost factor relationship between high and low performance group does not have a significant difference on the performance of strategic alliances. Second, the marketing factor of alliances characteristics has a positively significant influence on the financial and non-financial performance of strategic alliances. The high performance group's marketing factor has a great non-financial performance than low performance group, but the low performance group's marketing factor has a grater financial performance than high performance group factor does. Third, the service factor of alliances characteristics has a negative influence on the non-financial performance of strategic alliances. The high performance group's service factor has a great non-financial performance than low performance group. Based on the findings from this study, related implications and future avenues deserve to be discussed.

Case Study of Civil-BIM & 3D Geographical Information (3차원 지형자료와 토목 BIM의 사례적용 연구)

  • Park, Jae-Sun;Pyeon, Mu-Wook;Jo, Jun-Ho;Lee, Gun-Ho
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.6
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    • pp.569-576
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    • 2011
  • Recently the establishment of high accuracy 3D spatial information has been largely stimulated according to the increase in need of such 3D spatial information. In the fields of constructions and civil works, studies on increasing the productivity in these fields through converging them with other fields using the established 3D spatial information have been conducted. In such a tendency, BIM (Building Information Modeling) technologies have been rapidly applied to the fields of constructions and civil works. In particular, in the fields of constructions and civil works that represent a life span of plan-design-construction-maintenance, some BIM application methods and plans for the characteristics in each step have been proposed. Thus, the objective of this study is to simulate a project that is reasonable and can be optimized in connection with 3D spatial information and BIM technologies escaped from the conventional civil construction process that is based on empirical, statistical DB, and 2D information. For achieving this objective, 3D terrain data for the subject area engaged in this study using aerial photographs and airborne LiDAR was established. Also, a counter plan for the issues, which cannot be solved in the conventional methods for managing civil work projects, is applied through implementing bridge-based civil structure BIM by combining them with objective information.

Effects of Representation Forms on Analysts' Identification of Systems Development Problems - An Empirical Study -

  • Kim, Jong-Uk
    • Asia pacific journal of information systems
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    • v.10 no.2
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    • pp.71-95
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    • 2000
  • Despite repeated exhortation about the importance of social and human dimensions of systems development, socio-organizational issues continue to be neglected and ignored in the current information systems practice. A review of the human information processing literature suggests that the reasons for this continuing lack of attention to social issues may be found in the limitations of human cognition and information processing capacities. Bostrom and Heinen(1978) and Kumar and Bjorn-Anderson(1990) also suggest that the inadequate attention to social problems and issues by the analyst could originate from the analysts limited problem perception. This research explores how the representation forms of information systems(IS) methodology used in understanding and modeling the problem situation affect such systems development problem perception. Typically, a system development methodology prescribes the use of system models(i.e., system representations) to understand, analyze, evaluate, and design the information system. Given the size and complexity of information systems, and the abstraction and simplification underlying the modeling process, system representations usually depict only a limited set of aspects of the system. Thus, a methodology whose representations are limited to technical aspects will tend to limit the analyst's perspective to a technical one only(Kumar & Welke, 1990). Following the same line of argument, in contrast, it is the conjecture of this study that a methodology which specifies both social and technical aspects of IS development will help the analyst develop a more comprehensive view of the IS problem domain. Based on the above concept, a theoretical model was first developed which explained the systems analysts cognitive process. Drawing on this model, a research model was developed hypothesizing the impacts of representation forms on problem identification. The model was tested using a laboratory experiment with 70 individual subjects. A special computer software was developed with a hypermedia authoring tool to conduct the experiments in order to avoid experimenter biases and to maintain consistency in administrating repeated experiments. The program, designed to replace the experimenter, consisted of functions such as presenting the subjects with problem material, asking the subjects questions, and saving the typed answers of the subjects. The results indicate that representation forms strongly influence problem identification. It was found that the use of the socio-technical representation form led to the findings of more social problems than the use of technical representation form. The results imply significant effects of representation forms on problem findings and also suggest that the use of adequate representation forms may help overcome dysfunctional effects of our limited information processing capacity.

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The Effect of Clan Culture on Market Culture of Public Organization Focusing of Mediating Effect of Women Leader's Position and Carrier (글로벌기업의 집단형 문화가 합리형 문화에 미치는 영향 -여성 리더의 직위와 경력의 매개효과를 중심으로-)

  • Kim, Hyuk Young;Kim, Taek
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.2
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    • pp.271-280
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    • 2020
  • Purpose : The purpose of this study examines the mediating effect of women leader's characteristics in the relationship between clan culture and market culture of global companies. In addition, this study attempts to analysis the mediating effect of women leader's position and carrier in the relationship among facilitator, mentor, producer, and director leadership using partial mediation and completed mediation model. Research design, data, methodology : Conceptual research model is designed with three constructs such as clan culture, woemn leader's characteristics, and market culture. Based on five hundred cases with leadership styles and organizational culture of global companies, this study examine the mediating effect of women leader's characteristics in the relationship between clan culture and market culture using structured equation modeling. Results : Facilitator leadership have a significantly positive influence on women leader's position and carrier. Mentor leadership have a significantly positive influence on women leader's carrier while they are not correlated with mentor leadership and women leader's position. Women leader's position and carrier have a significantly positive influence on director leadership while women leader's position and carrier not have a positive influence on procucer leadership. Also facilitator and mentor leadership have a significantly positive on producer and director leadership. Conclusions : By controlling for the mediating effect of women leader's characteristics, this study have improved the academic contributions as well as policy and practical implications through empirical study of clan culture that affect market culture in the filds of leadership style and organizational. In addition, this study means that the mediating effects on the variables of women leader's position and carrier were examined.

Effects of Corporate Innovative Employees' Entrepreneurial Competencies on Performance: Based on Corporate Entrepreneurship and Entrepreneurial Performance (혁신조직 구성원의 기업가적 특성이 기대성과에 미치는 영향: 사내 기업가정신성과와 경영기대성과를 중심으로)

  • Han, Sangguk;Park, Jae-Whan
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.12 no.4
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    • pp.25-34
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    • 2017
  • In market-oriented, infinite competition era, even the world's top-tier companies can be collapsed suddenly. In order to continue to grow, a company must constantly introduce new value to the market. What is required in today's business environment is the manifestation of entrepreneurship. The purpose of this study is to examine the relationship between corporate entrepreneurship and business performance and organizational commitment. The results of the empirical analysis are based on the data from companies which have more than 20,000 employees and 30 years business history. Structural Equation Modeling analysis was conducted to confirm the relationship between corporate entrepreneurship, business performance, and organizational commitment. Also, multiple Regression Analysis was conducted to confirm the relationship between entrepreneurial competency, corporate entrepreneurship performance, and management expectation performance. The causality between latent variables was significant. As a result, it was proved that entrepreneurial competencies had the significant effect on both corporate entrepreneurship performance and management expectation performance. Also, the study result was proved that organizational commitment showed the mediating effect between entrepreneurial competencies and corporate entrepreneurship performance. Based on the study results, the needs for developing individuals equipping entrepreneurial competencies was identified for increased business performance which was accomplished through the manifestation of entrepreneurship.

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Study on the simulation of a spark ignition engine using BOOST (상용 소프트웨어를 이용한 스파크 점화 기관의 시뮬레이션에 관한 연구)

  • Jeong, Chang-Sik;Woo, Seok-Keun;Ryu, Soon-Pil;Yoon, Keon-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.9
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    • pp.733-742
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    • 2016
  • In recent years, gas engines fueled with LNG or synthetic gas have been attracting considerable attention for marine use owing to their potential to facilitate better fuel economy and to reduce emissions. It has been confirmed that gas engines using the Otto cycle, which involves premixed combustion, can satisfy Tier III regulations without the EGR or SCR system. The objective of this study is to acquire simulation technologies for predicting gas engine performances in industrial fields. Using the commercial software BOOST, the simulation is conducted on a gasoline engine rather than a marine engine due to the gasoline engine's easier accessibility. This study consists of two stages. In the first stage published previously, the optimal modeling techniques for representing the behavior of the gas in the intake and exhaust systems were determined. In the current study, we formulated a method to evaluate the combustion and heat transfer processes in the cylinder and to ultimately determine the major performance parameters, given that the analytical model derived from the previous stage has been applied. Through this study, we were able to determine a combustion and heat transfer model and a valve discharge coefficient that are less reliant on empirical data: we were also able to formulate a methodology through which relevant constants are decided. We confirmed that the values of transient cylinder pressure variation, indicated mean effective pressure, and air supply can be successfully predicted using our modeling techniques.

Modeling of Near Fault Ground Motion due to Moderate Magnitude Earthquakes in Stable Continental Regions (안정대륙권역의 중규모지진에 의한 근단층지반운동의 모델링)

  • Kim, Jung-Han;Kim, Jae-Kwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.3 s.49
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    • pp.101-111
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    • 2006
  • This paper proposes a method for modeling new fault ground motion due to moderate size earthquakes in Stable Continental Regions (SCRs) for the first time. The near fault ground motion is characterized by a single long period velocity pulse of large amplitude. In order to model the velocity pulse, its period and peak amplitude need be determined in terms of earthquake magnitude and distance from the causative fault. Because there have been observed very few new fault ground motions, it is difficult to derive the model directly from the recorded data in SCRs. Instead an indirect approach is adopted in this work. The two parameters, the period and peak amplitude of the velocity pulse, are known to be functions of the rise time and the slip velocity. For Western United States (WUS) that belongs active tectonic regions, there art empirical formulas for these functions. The relations of rise time and slip velocity on the magnitude in SCRs are derived by comparing related data between Western United States and Central-Eastern United States that belongs to SCRs. From these relations, the functions of these pulse parameters for NFGM in SCRs can be expressed in terms of earthquake magnitude and distance. A time history of near fault ground motion of moderate magnitude earthquake in stable continental regions is synthesized by superposing the velocity pulse on the for field ground motion that is generated by stochastic method. As an demonstrative application, the response of a single degree of freedom elasto-plastic system is studied.

The Impact of Service Quality(Performance Work, Price, Physical Environment) on Customer Satisfaction, Trust, and Intention to Re-attend Ballet Performances : US Localization of K-ballet Content (발레공연의 서비스 품질(작품, 가격, 물리적 환경)이 만족, 신뢰, 재 관람의도에 미치는 영향: K-발레 콘텐츠 미국 현지화를 중심으로)

  • Kim, Kwangjin
    • The Journal of the Korea Contents Association
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    • v.21 no.10
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    • pp.149-162
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    • 2021
  • This study aims to conduct an empirical analysis on the impact of service quality (performance work, price, physical environment) on customer satisfaction, trust and intention to re-attend ballet performances. Another focus of the research is to examine the structural effect of satisfaction and trust on customer's intention to re-attend. This study surveyed 240 adults (Americans) who have physically attended ballet performances from 2019 to 2020. Applying the structural equation modeling analysis using the software SmartPLS, this study investigates 240 valid responses obtained from a global research institute in a mid-August 2020 survey. The findings of the analysis are as follows. (1) Performance work is positively correlated with customer satisfaction, while price and physical environment do not affect customer satisfaction. (2) Performance work is positively correlated with customer trust. However, price and physical environment haven't been observed to affect customer trust. (3) Customer satisfaction is positively correlated with customer trust. (4) Performance work, price and physical environment do not affect customer's intention to re-attend ballet performances. (5) Customer satisfaction is positively correlated with customer intention to re-attend performances. (6) Customer trust is positively correlated with the intention to re-attend performances.

Is Political Polarization Reinforced in the Online World?: Empirical Findings of Comments about News Articles (온라인 공간의 정치 양극화는 심화될 것인가?: 선거 기사 댓글에 대한 경험적 분석)

  • Eom, Ki-Hong;Kim, Dae-Sik
    • Informatization Policy
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    • v.28 no.4
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    • pp.19-35
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    • 2021
  • The purpose of this research is to investigate the attributes of the online world and to analyze their influence on democracy. The research focuses on the mayoral by-elections that were held in Seoul and Busan, South Korea, on April 4, 2021. The study demonstrates the characteristics of online spaces and the polarization of the online public through news articles and user comments from the Internet. The research includes topic modeling to measure the diversity of media reports, sentiment analysis to measure online public opinion, and interrupted time series analysis to understand how a particular event influences online attitudes. A combination of these methods is used to attempt to estimate the strength of political polarity in the online environment. The study shows diverse media reports by election region and candidate, where the online public repeatedly reveals high negative and low positive attitudes towards each candidate. Moreover, political polarity can differ based on the level of interest in an election. Although voters pay less attention to a by-election than a presidential election, there is a solid political polarity in the online world. Hence, the research recommends preparing measures to alleviate the polarization as politics requires significant online participation.