• Title/Summary/Keyword: Power law relationship

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Legal Issues of Urban Parks as a Reservation Area in the Initial Legislation on Urban Parks in Korea and the Implementation of the Park Act (1967~1980) (우리나라 도시공원 관련 초기 법률 입안과 「공원법(1967~1980년)」 시행과정에서 나타난 유보지로서 도시공원에 관한 제도의 문제)

  • Oh, Chang-Song
    • Journal of the Korean Institute of Landscape Architecture
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    • v.46 no.3
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    • pp.103-116
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    • 2018
  • The Park Act (1967~1980) was the first law to define urban parks in Korea. The urban parks of that time were similar to a reservation area used for other purposes after giving regulation. Because 'the urban park as a reservation area' in the past is a repeated park issue in the present, it is necessary to consider the issues of the original law system that created the cause. From this perspective, this study analyzed the legislation to reserve an urban park by collecting bills and information about the factual relationship between 1960 70s park issues and the Park Act. Analysis showed that the reason for the adoption of different kinds of urban parks in the law of a nature park is that a negative list separated from the Urban Planning Act is required to curb private usage. Inherent in the Park Act, however, was the problem of allowing the encroachment of urban parks by governmental power. (1) The Park Act sets out a wide range of cases to abolish urban park. (2) Unclear setting of governmental power could abuse the urban park. (3) Insufficient standards were able to erode the urban park with large for-profit facilities. (4) The inactivity of the Urban Public Park Committee had reduced democratic decision-making and professional judgement on park issues. Therefore, the Park Act was characterized as infringing on the environment and right to urban parks and took a passive attitude in creating parks and in citizen usage thereof. The Park Act had limitations as a progenitor for establishing the characteristics and concepts of urban parks.

Keyword Network Analysis for Technology Forecasting (기술예측을 위한 특허 키워드 네트워크 분석)

  • Choi, Jin-Ho;Kim, Hee-Su;Im, Nam-Gyu
    • Journal of Intelligence and Information Systems
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    • v.17 no.4
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    • pp.227-240
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    • 2011
  • New concepts and ideas often result from extensive recombination of existing concepts or ideas. Both researchers and developers build on existing concepts and ideas in published papers or registered patents to develop new theories and technologies that in turn serve as a basis for further development. As the importance of patent increases, so does that of patent analysis. Patent analysis is largely divided into network-based and keyword-based analyses. The former lacks its ability to analyze information technology in details while the letter is unable to identify the relationship between such technologies. In order to overcome the limitations of network-based and keyword-based analyses, this study, which blends those two methods, suggests the keyword network based analysis methodology. In this study, we collected significant technology information in each patent that is related to Light Emitting Diode (LED) through text mining, built a keyword network, and then executed a community network analysis on the collected data. The results of analysis are as the following. First, the patent keyword network indicated very low density and exceptionally high clustering coefficient. Technically, density is obtained by dividing the number of ties in a network by the number of all possible ties. The value ranges between 0 and 1, with higher values indicating denser networks and lower values indicating sparser networks. In real-world networks, the density varies depending on the size of a network; increasing the size of a network generally leads to a decrease in the density. The clustering coefficient is a network-level measure that illustrates the tendency of nodes to cluster in densely interconnected modules. This measure is to show the small-world property in which a network can be highly clustered even though it has a small average distance between nodes in spite of the large number of nodes. Therefore, high density in patent keyword network means that nodes in the patent keyword network are connected sporadically, and high clustering coefficient shows that nodes in the network are closely connected one another. Second, the cumulative degree distribution of the patent keyword network, as any other knowledge network like citation network or collaboration network, followed a clear power-law distribution. A well-known mechanism of this pattern is the preferential attachment mechanism, whereby a node with more links is likely to attain further new links in the evolution of the corresponding network. Unlike general normal distributions, the power-law distribution does not have a representative scale. This means that one cannot pick a representative or an average because there is always a considerable probability of finding much larger values. Networks with power-law distributions are therefore often referred to as scale-free networks. The presence of heavy-tailed scale-free distribution represents the fundamental signature of an emergent collective behavior of the actors who contribute to forming the network. In our context, the more frequently a patent keyword is used, the more often it is selected by researchers and is associated with other keywords or concepts to constitute and convey new patents or technologies. The evidence of power-law distribution implies that the preferential attachment mechanism suggests the origin of heavy-tailed distributions in a wide range of growing patent keyword network. Third, we found that among keywords that flew into a particular field, the vast majority of keywords with new links join existing keywords in the associated community in forming the concept of a new patent. This finding resulted in the same outcomes for both the short-term period (4-year) and long-term period (10-year) analyses. Furthermore, using the keyword combination information that was derived from the methodology suggested by our study enables one to forecast which concepts combine to form a new patent dimension and refer to those concepts when developing a new patent.

The Effects of Object Size and Travel Distance on Human Speed Perception (물체의 크기와 이동거리에 따른 속도감 변화)

  • Park, Kyung-Soo;Choi, Jeong-A;Lee, Eun-Hye
    • Journal of the Ergonomics Society of Korea
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    • v.24 no.2
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    • pp.51-56
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    • 2005
  • Human perceptional speed is different from its real speed. There is lack of research that the perceptional speed is different from real speed in 2-dimension, because most research of speed perception has concentrated on points and lines. This research investigates the effects of object size on speed perception. In this research, we used 2-D circular objects of the different size, 0.9, 1.8 and $3.6^{\circ}$. The objects moved 9.0, 13.5 and $18.0^{\circ}$ with three different speeds, 6.0, 9.0 and $18.0^{\circ}$/s. Six participants were exposed to the environment with standard scene(size: $1.8^{\circ}$, speed: $9.0^{\circ}$/s and travel distance: $13.5^{\circ}$). After the first scene, another scene in which the object had changed to different sizes, speeds and distances, was shown to the participants. A magnitude estimation method was used to construct a scale of the perceived speed level. The relationship between the perceived and the actual speed level was explained by Stevens's power law that the value was 0.978 with the exponent of 0.992. The size of object had an effect on the speed perception but travel distance was not. The perceptional speed of bigger object was lower than of smaller object. It showed that the degrees of perceptional speed decreased as size of object increased.

A Study on Fatigue Crack Propagation Behavior in Random Short-Fiber SMC Composites (비규칙 단섬유강화 SMC 복합재료의 피로균열 전파거동에 관한 연구)

  • Kim, Jae-Dong;Koh, Sung-Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.26 no.2
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    • pp.204-212
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    • 1990
  • The SMC composite, now being considered in certain structural applications, is anticipated to experience repeated loading during service. Thus, understanding of the fatigue behavior is essential in proper use of the composite material. In this paper, using the SMC composite composed of E-glass chopped strand and unsaturated polyester resin three point bending fatigue tests are carried out to investigate the fatigue crack propagating behavior under various cyclic stresses and fatigue damage of various microcrack forms. The following results are obtained from this study; 1) Most of the total fatigue life of the SMC composite is consumed at the initial extension or the growth of the macroscopic crack. 2) A Paris' type power-law relationship between the crack propagation rate and stress intensity factor range is obtained, and the value of material constant m is much higher (m=9~11)than that of other metals. 3) In case of high cyclic stress the fatigue damage show high microcrack density and short crack length, but in case of low cyclic stress does it vice versa. 4) Fatigue damage is characterized by microcrack density, crack length and distribution of crack orientation.

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Performance of Evaporation Heat Transfer Enhancement and Pressure Drop for Liquid Nitrogen (액체질소에 대한 증발 열전달 촉진 및 압력강하 성능)

  • Nam, Sang-Chul;Lee, Sang-Chun;Park, Byung-Duck
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.3
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    • pp.363-372
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    • 2000
  • An experiment was carried out to evaluate the heat transfer enhancement and the pressure drop characteristics for liquid nitrogen using wire-coil-insert technique under horizontal two-phase conditions. The tube inner diameters were 8 mm and 15 mm, respectively and the tube length was 4.7 m. The helix angle of the wire coil insert was $50^{\circ}$ and its length was 4.7 m. Heat transfer coefficients for both the plain and the enhanced test tubes were calculated from the measurements of temperatures, flow rates and pressure drops. A correlation in a power-law relationship of the Nusselt number, Reynolds number and Prandtl number for the heat transfer was proposed which can be available for design of cryogenic heat exchangers. The correlation showed that heat transfer coefficients for the wire-coil inserts were much higher than those for plain tubes, increased by more than $1.8{\sim}2.0$ times depending upon the range of the equivalent Reynolds number. The correlation was compared with other various correlations in the turbulent flow conditions.

Research about Recognition of Government Officials Regarding Korean Disaster Management System in Charge (한국 재난관리체계에 대한 담당공무원들의 인식에 관한 연구)

  • Lee, Jung-Il
    • Fire Science and Engineering
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    • v.24 no.5
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    • pp.10-25
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    • 2010
  • As disaster potential power of modern society grows larger, to improve and reinforce efficiently a national system which prepares and responds disasters, analyzed the survey for government officials of the department disaster management. Following is the contents of this research. First, cooperative relationship to disaster management organizations. Second, necessity of law establishment related crisis and disaster department. Third, by recognition regarding disaster management situational variable, overall recognition regarding disaster management situation, overall recognition regarding crisis type, recognition regarding occurrence possibility along disaster scale. Fourth, by recognition regarding structural variable of disaster management, the National Emergency Management Agency regarding disaster management, related organization, recognition difference of local government. It is a research about confusion regarding step of prevention - preparation - correspondence - restoration.

Small and Large Deformation Rheological Behaviors of Commercial Hot Pepper-Soybean Pastes

  • Choi, Su-Jin;Kang, Kyoung-Mo;Yoo, Byoung-Seung
    • Food Science and Biotechnology
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    • v.15 no.6
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    • pp.871-876
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    • 2006
  • Rheological behavior of commercial hot pepper-soybean paste (HPSP) was evaluated in small amplitude oscillatory and steady shear tests. Storage modulus (G'), loss modulus (G"), and complex viscosity (${\eta}^*$) as a function of angular frequency (${\omega}$), and shear stress (${\sigma}$) as a function of shear rate (${\gamma}$) data were obtained for 5 commercial HPSP samples. HPSP samples at $25^{\circ}C$ exhibited a non-Newtonian, shear-thinning flow behavior with high yield stresses and their flow behaviors were described by power law, Casson, and Herschel-Bulkley models. Time-dependent flow properties were also described by the Weltman, Hahn, and Figoni & Shoemaker models. Apparent viscosity over the temperature range of $5-35^{\circ}C$ obeyed the Arrhenius temperature relationship with activation energies (Ea) ranging 18.3-20.1 kJ/mol. Magnitudes of G' and G" increased with an increase in ${\omega}$, while ${\eta}^*$ decreased. G' values were higher than G" over the most of the frequency range (0.63-63 rad/sec), showing that they were frequency dependent. Steady shear viscosity and complex viscosity of the commercial HPSP did not fit the Cox-Merz rule.

Effect of Porosity on Quality Index of Tensile Property of A356 Casting Alloys (A356합금의 품질지수에 미치는 미소기공율의 영향)

  • Lee, Choong-Do
    • Journal of Korea Foundry Society
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    • v.38 no.5
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    • pp.95-102
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    • 2018
  • The dependence of the tensile properties on variations in the porosity of A356 aluminium alloys was investigated in terms of the quality index of the tensile properties based upon the ultimate tensile strength and elongation as well as the variation of the strength coefficient and strain-hardening exponent with regard to a T6 treatment. The test specimens were prepared by low-pressure die-casting and a subsequent T6 treatment, and the experimental results of a tensile test carried out at room temperature were compared to the theoretical description using a modified constitutive model. The nominal value of the quality index of A356 alloys increases gradually with a lapse of the ageing time upon a T6 treatment, despite the fact that this value is temporarily decreased during the initial stage of ageing from a solutionised condition. Additionally, the quality index depends practically upon the porosity variation with a power law relationship without regard to whether in solutionised or artificial aged conditions. The theoretical description indicates that the strength coefficient directly determines the nominal level of the quality index. Moreover, the overall dependence of the quality index on the porosity variation is remarkably weakened with an increase in the tensile strain, whereas the quality index depends sensitively upon the porosity variation with a low value of the strain-hardening exponent.

The Analysis on Causal Relationship between Business Startup Education and Entrepreneurial Intention

  • Hwang, Gyu-Sam;Kim, Hye-Sook;Park, Dae-Sub
    • Journal of Distribution Science
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    • v.15 no.3
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    • pp.27-37
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    • 2017
  • Purpose - The current study analyzes the effect of business startup education on business startup education satisfaction and entrepreneurial intention. Also, it attempts to discover if business startup confidence plays a moderating role between business startup education satisfaction and entrepreneurial intention. Research design, data, and methodology - The survey was conducted for approximately 60 days, from July 20, 2016 to September 20, 2016, and distributed to 300 restaurant founders who started their business through business startup education provided by Korea Food Service Industry Association in Seoul, Kyungki and Incheon or existing business founders. Results - Per multiple regression analysis of business startup education and business startup education satisfaction, among business startup education, all law, entrepreneurship, commercial power analysis, and practical education have significantly positive effect. Per simple regression analysis of business startup education satisfaction and entrepreneurial intention, business startup education has significantly positive effects on entrepreneurial intention. Business startup education satisfaction and business startup confidence interaction show that they do not have a moderating role between business startup education satisfaction and entrepreneurial intention. Conclusions - Setting up theoretical reasoning, this study supports conclusions drawn by prior studies: business startup education has significantly positive effects on business startup education satisfaction and entrepreneurial intention.

A Study on the Reinforcement of the competitive power of Korean Inland Fisheries (우리나라 내수면어업의 경쟁력 강화 방안)

  • Kim, Dae-Young
    • The Journal of Fisheries Business Administration
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    • v.39 no.3
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    • pp.111-137
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    • 2008
  • Fisheries resources living in inland have continuously reduced due to over-fishing and development thoughtless for the environment. Inland fisheries that target the fisheries resources have been also confronted by several problems such as insufficiency of inland fisheries management systems, inconsistent fisheries management system, inferior infrastructure of inland fisheries, and decreasing fishermen's real income. These problems have demotivated fishermen who want to focus on fishing and farming activation. Therefore, this paper provides alternatives of reorganization for turning to sound and healthy inland fisheries industries by reviewing Korean inland fisheries management systems. The reorganization should be preferentially granted resource management by water system considering geographical conditions, seed release, and establishment of fisheries order for maintenance of sound and healthy inland fisheries. Also, the reorganization should be moved toward the competitive strengthening of "company unit" for inland fisheries, the nourishment of fisher-oriented fisheries management system, strong relationship among inland fishermen, the systematic management of inland fisheries, the strengthening of guidance service for inland fisheries, the extension of infrastructure related to fisheries production, the development of inland fisheries policy including public people, and the improvement of inland fisheries system and law reflecting various users of inland fisheries.

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