• Title/Summary/Keyword: theoretical analyses

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Thermal Decomposition and Combustion Behavior of Plastics into Blast Furnace (플라스틱의 高爐 吹入時 熱分解特性 및 燃燒擧動)

  • 허남환;백찬영;임창희
    • Resources Recycling
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    • v.9 no.6
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    • pp.15-22
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    • 2000
  • There are many intensive efforts to develop the recycling technologies of waste plastics in steel works to tackle the saving of resources and the protection of the natural environment. In this study, the thermogravimetric analyses for three kinds of plastics, the combustion experiments and the theoretical approach for calculating the flame temperature in the blast furnace had been performed to understand the behavior of plastics in the raceway. The thermal decompositions of plastics were studied using thermogravimetric analyzer under the atmospheric condition. The starting temperature of thermal decomposition and the maximum weight loss point were increased in proportion to the logarithmic values of heating rate. The combustion characteristics of plastics were simulated in a coke-bed combustor. The combustion efficiency of plastics was lower than that of pulverized coal. The oxygen enrichment was found out to be one of the useful methods to increase the combustibility of plastics in raceway. The maximum injection rate of plastics was calculated based on the flame temperature.

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SAR Clutter Image Generation Based on Measured Speckles and Textures (지표면 별 영상잡음과 영상질감을 이용한 SAR 클러터 영상 생성)

  • Kwon, Soon-Gu;Oh, Yi-Sok
    • Korean Journal of Remote Sensing
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    • v.25 no.4
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    • pp.375-381
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    • 2009
  • In this paper, synthetic aperture radar (SAR) clutter images are simulated based on the extensive analyses for radar backscatter characteristics of various earth surfaces, and the simulated images are compared with measured SAR images. At first, the surface parameters including soil moisture content and surface roughness parameters and other parameters for vegetation canopies are measured for various surfaces. The backscattering coefficients for the surfaces are computed using theoretical and empirical models for surface scattering and the radiative transfer for vegetation-canopy scattering. Then, the digital elevation map (DEM) and land cover map (LCM) are used for the SAR image generation. The SAR impulse response (correlation function) is also employed to simulated reliable SAR images. Finally, the appropriate speckle and texture parameters for various earth surfaces are used for generating the SAR clutter images.

Refutation against the Non-Scientificity Argument on Korean Medicine (한의학의 비과학성 논란에 대한 반박)

  • Chi, Gyoo Yong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.33 no.5
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    • pp.249-254
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    • 2019
  • This study is aimed to refute against medical opponent's claim that Korean medicine does not conform to the conditions of science. Analyses and refutations against a journal treatise and a Facebook column formally written for a logical criticism and attack were conducted. As an example of the logic of the knowledge production process in Chinese medicine, 8 principle theory was exemplified in the Han danasty Classics "Neijing" and "Shanghanlun" at first. The knowledge was continuously revised and accumulated historically and then completed through Ming、Cheng period. The differential diagnosis and treatment theory is a logical process of forming knowledge through the process of abduction, deduction and induction begun from "Shanghanlun" succeeded to nowadays and it is essentially equaled with the process of experimental inference by Claude Bernard. Examples of normal science status based on Kuhn's scientific standards include the theory of 8 principle, differntial diagnosis of viscera and bowel, 3 yang and 3 yin diseases of "Shanghanlun" and warm disease theory. Examples of science lost or get its normal status by refutation following Popper's standards were cold damage theory and warm disease theory respectively. This allowed Chinese medicine to follow the general principles of science that form scientific knowledge and to correspond with the demarcation standards and concepts of science. However, as one of the conditions for becoming a science, Chinese medicine is partially lacking in terms of the interpretation of text language or the accordance with modern knowledge. Therefore methods are required to supplement this lack through multi-faceted research such as literature-based, theoretical and clinical studies.

On the Removal of Irregular Frequencies in the Prediction of Ship Motion in Waves (파랑중에서 전진동요하는 선박의 특이파수 억제에 관한 연구)

  • H.Y. Lee;D.J. Yum
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.4
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    • pp.73-81
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    • 1994
  • The source and source/dipole distribution methods using 3-dimensional panel method have been widely used for ship motion analysis. When these methods are used, large errors in the predicted hydrodynamic coefficients are introduced around the irregular frequencies caused by the resonance of imaginary internal flow. Therefore, the irregular frequencies need to be removed for an accurate prediction of ship motion. This paper adopts 3-dimensional translating and oscillating Green function derived by Wu. The adaptive integration method, stretching transform and stationary phase method are used for the calculation of the calculation of Green function and the integral equation is derived by distributing the Green function n ship surface and inner free-surface. The condition of zero normal velocity, that is, wall condition on inner free-surface has been successfully used for the removal of irregular frequencies in oscillating problems. The calculations are carried out for series 60($C_B=0.7$) vessel and the results are compared with those of other theoretical analyses and experiment.

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The Theory of Load Estimation Method and Case Study of Hydraulic Breaker for Rock Drilling (진동기반 하중 추정기법의 이론 및 암반 천공용 유압 브레이커 적용사례)

  • Kim, Dae-ji;Cho, Jung-Woo;Oh, Joo-Young;Chung, Jintai;Song, Changheon
    • Tunnel and Underground Space
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    • v.29 no.3
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    • pp.135-147
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    • 2019
  • This paper introduced a impact load estimation method by examining vibration transfer path analysis (TPA). The theoretical background and the load quantification procedure are explained, and a case study of hydraulic breaker is reported. We explained the merits and limitations of the load estimation method of TPA, and improvement method was suggested through case analyses of drilling equipment. The necessity of R&D of load-estimation technology was discussed. A new strategy for developing new techniques for impact load measurement was proposed.

Plastic Hinge Modeling Based on Lumped Plasticity using a Generalized Finite Element Method (일반유한요소법을 이용한 집중소성힌지 모델링)

  • Son, Hong-Jun;Rhee, Seung-Ho;Kim, Dae-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.6
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    • pp.381-388
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    • 2018
  • This paper presents a generalized finite element formulation for plastic hinge modeling based on lumped plasticity in the classical Euler-Bernoulli beam elements. In this approach, the plastic hinges are effectively modeled using proper enrichment functions describing weak discontinuities of the solution. The proposed methodology enables the insertion of plastic hinges at an arbitrary location without modifying the connectivity of elements. The formations of plastic hinges are instead achieved by hierarchically adding degrees of freedom to existing elements. Convergence analyses such as h- and p-extensions are performed to investigate the effectiveness of the proposed method. The analysis results indicate that the proposed generalized finite element method can achieve theoretical convergence rates for both cases where plastic hinges are located at nodes and within an element, thus demonstrating its accuracy.

The Organization Performance Reinforcement by a Utilization Level of the Smart Work (스마트워크 활용 수준에 따른 조직성과 강화에 관한 연구)

  • Jung, Byoungho
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.14 no.4
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    • pp.189-204
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    • 2018
  • The purpose of this study is to examine an organizational performance difference by individual utilization level of the smart work. The Smart work help minimizing business process and improving organization productivity based on information technology. This new technology provides a flexible way of the task through smart-work center, videoconferencing, telecommuting, mobile(remote control) and business-only messenger. This investment changes organizational culture, institutions and behavior by new technology applying. The organization system change due to smart work has trouble between alteration preferences and existing maintains a group. In response, the organization should make investment justification of smart work for institutional and culture stabilized by a new system in organization. I set up the analytical process of four stages for empirical research. It will analyze an operation difference of the smart work between pre and post investment in the first-step analysis. The two-step analysis will conduct a text mining analysis of smart work operations. The three-step analysis will identify organization performance differences among individual levels in smart work. The four-step analysis will identify a factor difference in organizational performance by individual utilization level on smart work. According to the study, It has been revealed a difference between the pre and post investment performance on smart work. The text mining analyses many appeared an improvement opinion of organizational culture. Next, there is a difference in organization performance among utilize groups of smart work. Furthermore, the factors of organizational performance among groups appeared differently. The theoretical contribution of this study provided to expand the organizational theory of organization change and resistance. The practical implications provided to require a strong guideline an organizational culture and institution for smart work.

A Review of Studies on the Influence of SME's Technological Innovation on National and Regional Economies (중소기업 기술혁신이 국가 및 지역경제에 미치는 영향에 대한 선행연구 고찰)

  • Jeon, Bong-Kyung
    • Journal of the Economic Geographical Society of Korea
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    • v.22 no.1
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    • pp.84-95
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    • 2019
  • The competence of SME's technological innovation is deemed as one of the crucial factors in national and regional economies. Yet, as seen in previous studies, there is a dearth of studies on this subject, and policy and academic circles had been inclined to relatively underestimate the contribution of the SMEs to economies and industries (such as, job creation and GDP contribution). Generally, there is a bias that the innovative activity of the large-sized firm is likely to perform better than that of the small-sized company. According to several case studies, however, SME possesses a more appropriate form for innovative activities, and significantly contributes to creating advanced industrial agglomeration. Hence, this study analyses the contribution of the SME innovation to the national and regional economy along with analysing the extant literature. In doing so, we can reason out theoretical and policy implications.

The Effect of Small Firm CEOs' Transformational Leadership on Employees' Innovative Behavior (소기업 CEO의 변혁적 리더십이 직원의 혁신행동에 미치는 영향)

  • Kim, Yong-Mook;Shin, Ho-Chul
    • Journal of Korean Society for Quality Management
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    • v.47 no.1
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    • pp.59-74
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    • 2019
  • Purpose: Despite the fact that the majority of domestic firms are small in size, there have been few studies conducted to understand the leadership effectiveness of small firm CEOs. Based on the upper echelon theory, this study attempts to demonstrate empirically that transformational leadership of small firm CEOs can increase the innovative behavior of employees. In addition, the present study examines mediating effects of CEO trust perceived by employees when transformational leadership affects employees' innovative behavior. Methods: The survey data of CEOs'transformational leadership, innovative behavior of employees, and perceived CEO trust were collected from 176 employees working in domestic small firms. Hierarchical regression analyses were performed to examine the main effects between transformation leadership and innovative behavior and mediating effects of CEO trust perceived by employees. Results: The results show that CEOs' transformational leadership is significantly related to the innovative behavior of employees in the current sample. Results also indicate that CEO trust perceived by employees reveals a mediating effect in the process of transformational leadership affecting innovative behavior. Conclusion: The results show that as suggested by the upper echelon theory, the leadership of small firm CEOs can have a significant impact on positive job-related behaviors and attitudes of employees. The results also contribute to expand on the understanding of the relationship between transformational leadership and innovative behavior by explaining that transformational leadership can mediate trust in CEOs in enhancing employees'innovative behavior. Theoretical and practical implications are reviewed, and limitations of the study and suggestions for future research are addressed.

Proactive Personality, Knowledge Sharing Behavior, Job Characteristics, and Organizational Recognition: An Application of Costly Signaling Theory (주도적 성격과 지식 공유행위, 직무 특성, 그리고 조직의 인정 간 관계에 관한 연구: 비싼 신호보내기 이론을 중심으로)

  • Park, Jisung;Chae, Heesun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.128-137
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    • 2018
  • Drawing on costly signaling theory and self-enhancement motive, this study examines the relationships among proactive personality, knowledge sharing behavior, and organizational recognition. In addition to the individual characteristic, this study considers job characteristics as conditional factors, and especially proposes the moderated mediation model in which job complexity and variety moderate the relationships among proactive personality, knowledge sharing behavior, and organizational recognition. To prove these hypotheses, empirical analyses are conducted with 166 dyad samples collected from various industries. As predicted, individuals with high proactive personality are more likely to become involved in knowledge sharing behavior, and this behavior increases organizational recognition rated by their supervisors. Moreover, job complexity and variety moderate the positive relationship between proactive personality and organizational recognition is mediated by knowledge sharing behavior. These results reveal the motive in knowledge sharing and the boundary condition that is necessary to increase such behavior. The study findings will ultimately contribute theoretical and empirical implications to the knowledge management literature.