• Title/Summary/Keyword: model stability

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Smart City Energy Inclusion, Towards Becoming a Better Place to Live

  • Cha, Sang-Ryong
    • World Technopolis Review
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    • v.8 no.1
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    • pp.59-70
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    • 2019
  • Where is a better place to live? In the coming era, this should be more than simply a livable place. It should be an adaptable place that has a flexible system adaptable to any new situation in terms of diversity. Customization and real-time operation are needed in order to realize this technologically. We expect a smart city to have a flexible system that applies technologies of self-monitoring and self-response, thereby being a promising city model towards being a better place to live. Energy demand and supply is a crucial issue concerning our expectations for the flexible system of a smart city because it is indispensable to comfortable living, especially city living. Although it may seem that energy diversification, such as the energy mix of a country, is a matter of overriding concern, the central point is the scale of place to build grids for realizing sustainable urban energy systems. A traditional hard energy path supported by huge centralized energy systems based on fossil and nuclear fuels on a national scale has already faced difficult problems, particularly in terms of energy flexibility/resilience. On the other hand, an alternative soft energy path consisting of small diversified energy systems based on renewable energy sources on a local scale has limitations regarding stability, variability, and supply potential despite the relatively light economic/technological burden that must be assumed to realize it. As another alternative, we can adopt a holonic path incorporating an alternative soft energy path with a traditional hard energy path complimentarily based on load management. This has a high affinity with the flexible system of a smart city. At a system level, the purpose of all of the paths mentioned above is not energy itself but the service it provides. If the expected energy service is fixed, the conclusive factor in choosing a more appropriate system is accessibility to the energy service. Accessibility refers to reliability and affordability; the former encompasses the level of energy self-sufficiency, and the latter encompasses the extent of energy saving. From this point of view, it seems that the small diversified energy systems of a soft energy path have a clear advantage over the huge centralized energy systems of a hard energy path. However, some insuperable limitations still remain, so it is reasonable to consider both energy systems continuing to coexist in a multiplexing energy system employing a holonic path to create and maintain reliable and affordable access to energy services that cover households'/enterprises' basic energy needs. If this is embodied in a smart city concept, this is nothing else but smart energy inclusion. In Japan, following the Fukushima nuclear accident in 2011, a trend towards small diversified energy systems of a soft energy path intensified in order to realize a nuclear-free society. As a result, the Government of Japan proclaimed in its Fifth Strategic Energy Plan that renewable energy must be the main source of power in Japan by 2050. Accordingly, Sony vowed that all the energy it uses would come from renewable sources by 2040. In this situation, it is expected that smart energy inclusion will be achieved by the Japanese version of a smart grid based on the concept of a minimum cost scheme and demand response.

Review on Applicability of Local Scour Depth Calculation Formula in River (하천 세굴심 산정을 위한 교각 세굴심 산정식의 적용성 검토)

  • Min, ByungYun;Chang, HyungJoon;Lee, HoJin;Kim, SungDuk
    • Journal of Korean Society of Disaster and Security
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    • v.12 no.1
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    • pp.1-9
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    • 2019
  • The basic analysis of Soil and structural mechanics for the bridge substructure affected by the flow of water is sufficient in the construction of such bridges, but the stability of scour resulting from hydraulic phenomena is insufficient. In addition, it is not enough to estimate the scour depth of the bridge which reflects the watershed characteristics of the domestic river because it uses the formula for calculating the scour depth of the overseas piers in calculating the scour depth of the bridge. In this study, the application of the CSU (1993) formula, which is currently applied to the national river design criteria, was reviewed between the two formulas after calculating the scour after calculating the scour by applying another bridge deck scour calculation formula to take into account the uncertainty in the calculation of scour. In this study, in addition to the CSU (1993) formula, which is currently applied to Korean river design criteria, another scour depth calculation formula is applied to calculate uncertainty in scour depth calculation, was reviewed between the two formulas. The review confirmed that the SSE (%) showed a difference of at least 2.08%, up to 91.23%, and SSEn(%) at least 0.19%, up to 415.91%, when compared to the measured depth of the pier based on the hydraulic model experiment and the depth of the pier calculated with the nine scour depth formulas in use. In other words, it is confirmed that there are many differences between the scouring formulas of piers. The results of this study are expected to be used to estimate scour depth in future river design.

Analysis of the Convergent Relationship between Stress Factors and Depression Levels in a College Students (일개 대학생의 스트레스 요인 및 우울 수준의 융복합적 관련성 분석)

  • Lee, Hyun-Suk;Bae, Sang-Yun
    • Journal of Digital Convergence
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    • v.17 no.4
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    • pp.219-227
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    • 2019
  • This study examined the convergent relationship of stress factors related to the depression level(CES-D) of a college student. The questionnaire was used using an unregistered self-administered questionnaire for 304 students from a college located in J area from Nov. 12, 2018 to Dec. 14, 2018. The hierarchical multiple regression analysis results are as follows: The depression level of respondents turned out to be significantly higher in following groups: a group in which job seeking stress(CMI) is higher, a group in which academic burnout(MBI-SS) is higher, a group in which anxiety(BAI) are higher. The results show explanatory power of 60.7%. The results of the study indicate that the efforts, to decrease job seeking stress, to decrease academic burnout and, to decrease anxiety, are required to decrease the depression level among college students. These results can be utilized in various interventional efforts for academic counseling and guidance, job counseling, and psychological and emotional stability that lowers the depression level in college students. Following studies requires the presentation and analysis of structural models for the structural model that effects the depression levels of college students.

Development And Applying Detailed Competencies For Elementary School Students' Data Collection, Analysis, and Representation (초등학생의 데이터 수집, 분석, 표현 수업을 위한 세부역량 개발 및 적용)

  • Suh, Woong;Ahn, Seongjin
    • Journal of The Korean Association of Information Education
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    • v.23 no.2
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    • pp.131-139
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    • 2019
  • From 2019, software education has become a required subject for all elementary school students. However, many teachers are still unfamiliar with how the classes should be instructed. So this paper presented the meaning, detailed competencies and achievement standard in order to help in the collection, analysis and representation of data among the computational thinking that are key to software education. And it also suggested the applicability of the classes. The full course of the paper is summarized as follows. First, existing studies have summarized the meaning, detail and achievement standard of data related competencies. Based on this, a preliminary investigation was instructed. Pilot study carried out both FGI and closed questions at the same time. This was done in response to the survey's questionnaire reflecting the opinions of experts. Second, the results of the questionnaire generated as a result of the above were verified for validity, stability, and reliability among the PhD, PhD courses, software education teachers, and software education workers. Third, I developed and applied the five lessons as a class objective as 'Choosing collection method-Select the collection method according to the problem situation.', 'Searching for meaning of data-Understand what the analyzed data mean..', 'Using various expression methods-Use a variety of expression tools.' using the backward design model to integrate education, class, and assessment. As a result, the detailed competencies of data collection, analysis, and representation and achievement standard were presented. This may help in setting specific and specific criteria for what direction classes are recommended when planning data-related classes in elementary schools.

Argovian Cantonal School in Aarau and Albert Einstein I (칸톤학교 아라우와 아인슈타인 I)

  • Chung, Byung Hoon
    • Journal of The Korean Association For Science Education
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    • v.39 no.2
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    • pp.233-248
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    • 2019
  • This study shows that the Argovian Cantonal School in Aarau, Switzerland, which Albert Einstein attended from 1895 to 1896, had been closely related to the ideological education controversy in German Gymnasium throughout the 19th century. Due to this controversy, Einstein hardly received a formal science education in Bavaria. Despite the lack of formal education in Germany, he had a habit of self-studying from an early age and continued with this practice all through his life. He had a hard time at the authoritarian school in Munich, but at the democratic school in Aarau, where freedom and autonomy were secured, he was able to achieve emotional stability. For a long time, the city Aarau prevailed as a location of tolerance and multi-culturalism, without religious, regional, and national discrimination. This was possible due to the influence of external and unrestricted social mobility, as well as the Enlightenment from France. As a result, this small public school was able to acquire a mass of qualified human resources from outside of Switzerland. As a consequence of the controversy regarding the educational ideology, the Cantonal School adopted practical thoughts and the Enlightenment that fit the spirit of the times. The school consisted of two independent educational organizations: the Gymnasium, where the 'neuhumanistsch' education for the elite training was conducted, and the 'Gewerbeschule', where a more realistic education system was set up to suit the citizen life. In particular, after 1835, the Gymnasium changed gradually from the pure humanistic education to the 'utraquistisch' ways by introducing practical subjects such as natural history. Thereafter, the Cantonal School became an institution that was able to achieve a genuine humanity, academic, and civic life education. Einstein, who attended the 'technische Abteilung' of the 'Gewerbeschule,' considered this school as a role model of an institution that realized true democracy, and that left an unforgettable impression on him.

A study on ICO-based fund investment (ICO 기반 자금 투자에 대한 연구)

  • Yoo, Soonduck
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.5
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    • pp.25-32
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    • 2019
  • The purpose of this study is to investigate how to make a proper investment in ICO in the market. Previously, companies used to borrow money from banks or to obtain investments from venture capital (VC) and angel investors, but now ICOs are used as a new type of funding and financing model. The ICO sells the tokens or coins created on the blockchain openly online to raise the necessary funds, and provides the market value by paying the tokens or coins as much as the investment amount. According to this study, the limitations of the ICO market are (1) difficulties in evaluating the company, (2) uncertainties in investments, (3) lack of legal safeguards, and (4) measures to secure corporate stability after recruitment. At present, there is no way to cope with this systematically since the ICO is not protected in the legal framework. Nevertheless, we investigated the ways to make proper investment in the existing ICO market. In investing in ICO, investors should (1) consider investment methods and profitability, and (2) verify and judge investment fraud through various channels (ex. Homepage, composition team profile, etc.) and make investments based on this. This study will contribute to the formation of a healthy ICO market by understanding the newly emerged ICO market and studying the considerations when investing in it, thereby contributing to the right investor training and reducing the mass production of consumer damages caused by fraud. The limitation of this study is that the domestic ICO has not yet been examined in the legal framework, so further research is needed when policy changes occur in the future.

Cross-sector Job Mobility and Job Satisfaction Change among College Graduates (신규대졸자의 비영리영역과 영리영역 간 직업이동과 직무만족 변화)

  • Kang, Chul-hee;Huh, Soo-yeon;Lee, Jiman;Chung, Seungwha;Cho, Sang-mi
    • 한국사회정책
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    • v.19 no.2
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    • pp.9-38
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    • 2012
  • Little research has empirically examined cross-sector job mobility between non-profit and for-profit sector despite the rise and increased importance of this phenomenon in Korea. Using the panel data of Graduates Occupational Mobility Survey(GOMS) by the Korea Employment Information Service, this study attempts to examine changes in job satisfaction(overall score and 10 facet scores) associated with four types(retention at non-profits, turnover from non-profits to for-profits, turnover from for-profits to non-profits, and retention at for-profits) of cross-sector job mobility among college graduates by employing a first difference model. Major results reveal that (1) in the group of retention at non-profits, 'overall job satisfaction' is consistently higher; (2) in the group of retention at non-profits, negative change in 'overall job satisfaction' is the largest; (3) in the group of 'for-profits to non-profits,' negative change in 'stability of employment' is the smallest; (3) in the group of 'non-profits to for-profits,' negative change in 'job contents' is the smallest; (4) in the group of 'non-profits to for-profits,' negative change in 'weekly work hours' is the largest; (5) in the group of retention at non-profits, negative change in 'potential growth & development' is the largest; and (6) in the group of retention at non-profits, negative change in 'social reputation' is the smallest;. This study has made a start in a new area of inquiring attempting to explain cross-sector job mobility and raises implications for future research.

Effect of Re and Ru Addition on the Solidification and Solute Redistribution Behaviors of Ni-Base Superalloys (니켈계 초내열합금의 응고 및 용질원소의 편석 거동에 미치는 레늄 및 루테늄 첨가의 영향)

  • Seo, Seong-Moon;Jeong, Hi-Won;Lee, Je-Hyun;Yoo, Young-Soo;Jo, Chang-Yong
    • Korean Journal of Metals and Materials
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    • v.49 no.11
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    • pp.882-892
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    • 2011
  • The influence of rhenium (Re) and ruthenium (Ru) addition on the solidification and solute redistribution behaviors in advanced experimental Ni-base superalloys has been investigated. A series of model alloys with different levels of Re and Ru were designed based on the composition of Ni-6Al-8Ta and were prepared by vacuum arc melting of pure metallic elements. In order to identify the influence of Re and Ru addition on the thermo-physical properties, differential scanning calorimetry analyses were carried out. The results showed that Re addition marginally increases the liquidus temperature of the alloy. However, the ${\gamma}^{\prime}$ solvus was significantly increased at a rate of $8.2^{\circ}C/wt.%$ by the addition of Re. Ru addition, on the other hand, displayed a much weaker effect on the thermo-physical properties or even no effect at all. The microsegregation behavior of solute elements was also quantitatively estimated by an electron probe microanalysis on a sample quenched during directional solidification of primary ${\gamma}$ with the planar solid/liquid interface. It was found that increasing the Re content gradually increases the microsegregation tendency of Re into the dendritic core and ${\gamma}^{\prime}$ forming elements, such as Al and Ta, into the interdendritic area. The strongest effect of Ru addition was found to be Re segregation. Increasing the Ru content up to 6 wt.% significantly alleviated the microsegregation of Re, which resulted in a decrease of Re accumulation in the dendritic core. The influence of Ru on the microstructural stability toward the topologically close-packed phase formation was discussed based on Scheil type calculations with experimentally determined microsegregation results.

Characteristics of loci on Line-to-Earth Voltage according to Earth Fault in Earthing System for Ships (선박의 접지 시스템에서 지락 고장에 따른 대지 전압 변동 특성)

  • Kim, Jong-Phil;Ryu, Ki-Tak;Lee, Yun-Hyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.487-495
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    • 2021
  • The voltages mainly used in ships are 450 [V], 6.6 [kV], and 11 [kV], and an earthed system is applied to ensure the stability of the power distribution system. In general, low-voltage ships using 450 [V] apply an unearthed system, while high-voltage ships using 6.6 [kV] or 11 [kV] use a high-resistance earthed system. When an earth fault occurs in a ship's power distribution system, the voltage of the healthy phase increases to the line-to-line voltage or higher, which causes an excessive impact on the insulation of the cable. Thus, analyzing this behavior is very important. In this paper, we investigate the characteristics of the line-to-earth voltage variation according to earth faults and a recognition procedure of a faulty phase using the symmetrical coordinate method for a high-resistance earthed system and unearthed system. A mathematical model of the line-to-earth voltage was derived through the symmetric coordinate method, and the ship voltage for simulations was selected as 6.6 [kV] and 450 [V]. A MATLAB simulation proved that this method can determine the highest increase of the line-to-earth voltage, which leads by 120° on the faulty phase, and it accurately judges the faulty phase in both earthed systems.

A Study on Collaborative Governance: Focusing on the Cultural Heritage Guardians (문화재지킴이 정책의 협력적 거버넌스 운영 체계 연구)

  • Jang, Youngki
    • Korean Journal of Heritage: History & Science
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    • v.54 no.1
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    • pp.184-205
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    • 2021
  • Governance is valued as a new concept and principle of social operation and public policy management, and its influence is gradually expanding. Among the various governance theories being put into practice and in case analysis studies, collaborative governance embracing various governance concepts has been found to increase interdependence and responsibility beyond participation and compromise, and create new public values by integrating and utilizing optimal social coordination forms. In the field of cultural assets, governance-related research is also being conducted for the efficiency, sustainability, and scalability of public policy enforcement. This study explored the government's role (promotion, arbitration, and condition creation) in collaborative governance, focusing on the "Cultural Heritage Guardians" to understand how collaborative governance operates in the cultural heritage sector. Regarding governance policies in the cultural asset sector, the cultural asset guardians highlighted the status, role, and characteristics of policies by examining their introduction, development, and implementation. The results of the analysis revealed that private-led, horizontal public-private cooperation, collaborative governance, policy introduction, solidarity, professionalism, resource/knowledge imbalance, cooperation precedence, etc., facilitate increased participation. The government has accordingly proposed measures to establish comprehensive legal stability centered on cooperation; strategic reorganization of dedicated organizations; strengthened, supportive intermediate organizations; and individual and multi-party consultative bodies.