• Title/Summary/Keyword: Static and Dynamic Analysis

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Motion-based dance game's effect on the balance ability of the elderly Women (체감형 댄스게임이 여성노인의 균형능력에 미치는 효과)

  • Lee, Ji-Seol
    • Journal of Convergence for Information Technology
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    • v.8 no.4
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    • pp.73-80
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    • 2018
  • The purpose of this study was to investigate the effect of motion-based dance game on static and dynamic balance in elderly women. The participants were randomly divided into 2 group, Motion Based dance game group(n=10), control group(n=10). After they were divided into an Motion Based dance game group and a control group the Motion Based dance game group participated in six-week period of time, three times a week, 60 minutes each, and the control group didn't exercise outside of their daily lives. To evaluated the balance ability of exercise, it was evaluated by using Berg Balance Scale(BBS), Functional Reach Test(FRT), Timed Up and Go test(TUG). The data was analysis using a paired t-test and independent t-test to determine the statistical significance. The results of this study between BBS, FRT, TUG and Motion Based dance game group had statistically significant difference rather than control group(p<.05). In conclusion, the Motion based Dance Game showed improvement on the balance ability in the elderly. Regular maintenance of the Dance Game "Dance Central" program for the elderly will assistance improve the balance. Consequently, studies on the development of dance games suitable for the elderly are believed to be necessary.

Empirical Leisure Environment Satisfaction Evaluation of Public Institution Employees in Innocity (혁신도시 이전 공공기관 종사자의 여가활동 만족도에 영향을 미치는 요인 분석 -광주·전남 공동혁신도시를 중심으로-)

  • Baek, Min;An, Hyung-Soon
    • The Journal of the Korea Contents Association
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    • v.19 no.2
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    • pp.368-378
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    • 2019
  • With respect to the growth and development of innocity from improvements in leisure environments, this research examines the factors that affect the level of satisfaction of innocity leisure environments to propose political implications. In order to do so, 43 leisure activities were chosen, and the level of importance of those activities to the residents prior to moving to the innocity was compared to the level of satisfaction the residents felt regarding the activities after moving. As a result, 13 activities, including literature attendance, had greater levels of satisfaction after moving than the levels of importance prior to moving. The rest (30) activities showed the opposite results. We deduced the factors that affect the level of satisfaction by performing logistic regression analysis on 3 dependent variables. As a result, the static and passive leisure activities had higher satisfactory levels, whereas the dynamic and active had lower satisfactory levels. Thus, innocity must develop culture facilities quickly, expand exercise facilities to support sports activties, and promote tourism by improving and networking with tourist attractions in order to improve future satisfactory levels of leisure activities.

Collapse Modes of Steel Ordinary Concentrically Braced Frames According to Unbalanced Forces (불균형력에 따른 철골보통중심가새골조의 붕괴모드)

  • Park, Jin-Young;Kim, Seo-Yeon;Hong, Suk-Jae;Kim, Hyung-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.3
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    • pp.249-257
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    • 2015
  • The KBC2009 first introduces the requirements about vertical unbalanced forces into the design for steel ordinary concentrically braced frames(steel OCBFs), which forces them to easily meet the target seismic performance, called as the life safety performance objective under design based earthquakes(DBEs) pursuing in the KBC2009. However, there is little information on the effects of vertical unbalanced forces to the collapse prevention performance objective under maximum considered earthquakes(MCEs) which is another target seismic performance level implicitly prescribed in ASCE 7-10. It is valuable that the collapse capacities of steel OCBFs designed according to the KBC2009 are investigated. In this paper, the collapse modes of inverted V shaped steel OCBFs excited by MCEs are investigated. The prototype buildings of 5 story steel OCBFs are designed with different site conditions and three types of unbalanced forces are considered in the design stages. The prototype buildings are evaluated their seismic performances and collapse modes by nonlinear static analyses and nonlinear dynamic analyses. Analysis results show that the unbalanced forces significantly affect the seismic performance of the prototype buildings and proper considerations of unbalanced forces are required to achieve the desirable collapse mode and the collapse prevention performance objective.

Lightweight Design of a Vertical Articulated Robot Using Topology Optimization (위상최적화를 이용한 수직 다관절 로봇의 경량 설계)

  • Hong, Seong Ki;Hong, Jung Ki;Kim, Tae Hyun;Park, Jin Kyun;Kim, Sang Hyun;Jang, Gang-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1683-1688
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    • 2012
  • Topology optimization is applied for the lightweight design of three main parts of a vertical articulated robot: a base frame, a lower and a upper frame. Design domains for optimization are set as large solid regions that completely embrace the original parts, which are discretized by using three-dimensional solid elements. Design variables are parameterized one-to-one to the material properties of each element by using the SIMP method. The objective of optimization is set as the multi-objective form combining the natural frequencies and mean compliances of a structure for which load steps of interest are selected from the multibody dynamics analysis of a robot. The obtained results of topology optimization are post-processed to designs favorable to manufacturability for casting process. The final optimized results are 11.0% (base frame), 12.0% (lower frame) and 10.0% (upper frame) lighter with similar or even higher static and dynamic stiffnesses than the original models.

Early Null Pointer Check using Predication in Java Just-In-Time Compilation (자바 적시 컴파일에서의 조건 수행을 이용한 비어 있는 포인터의 조기검사)

  • Lee Sanggyu;Choi Hyug-Kyu;Moon Soo-Mook
    • Journal of KIISE:Software and Applications
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    • v.32 no.7
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    • pp.683-692
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    • 2005
  • Java specification states that all accesses to an object must be checked at runtime if object refers to null. Since Java is an object-oriented language, object accesses are frequent enough to make null pointer checks affect the performance significantly. In order to reduce the performance degradation, there have been attempts to remove redundant null pointer checks. For example, in a Java environment where a just-in-time (JIT) compiler is used, the JIT compiler removes redundant null pointer check code via code analysis. This paper proposes a technique to remove additional null pointer check code that could not be removed by previous JIT compilation techniques, via early null pointer check using an architectural feature called predication. Generally, null point check code consists of two instructions: a compare and a branch. Our idea is moving the compare instruction that is usually located just before an use of an object, to the point right after the object is defined so that the total number of compare instructions is reduced. This results in reduction of dynamic and static compare instructions by 3.21$\%$ and 1.98$\%$. respectively, in SPECjvm98 bechmarks, compared to the code that has already been optimized by previous null pointer check elimination techniques. Its performance impact on an Itanium machine is an improvement of 0.32$\%$.

An Analysis on BitTorrent Performance Based on the Number of Unchoked Peers (Unchoked Peer 개수에 따른 BitTorrent 성능 분석)

  • Chung, Tae-Joong;Han, Jin-Young;Kim, Hyun-Chul;Kwon, Tae-Kyoung;Choi, Yang-Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.8B
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    • pp.1197-1203
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    • 2010
  • A strength of BitTorrent, which is widely used for file sharing today, is due to its peer selection mechanism which is designed to encourage peers to contribute data. In the peer selection phase in BitTorrent, peers to upload the file in a swarm are selected by determining which peers upload the most to themselves. However, the number of peers to upload (i.e., number of unchoked peers) is fixed to four in its peer selection mechanism of BitTorrent, which yields inefficiency because the situation of the swarm may vary frequently (e.g., number of peers in the swarm, download rates, and upload rates). In this paper, we analyze the swarming system performance when the number of unchoked in BitTorrents is not static, but dynamic. For empirical investigation, we established a testbed in Seoul National University by modifying an open-source BitTorrent client, which is popular. Through our experiments, we show that an adaptive mechanism to adjust the number of unchoked peers considering the situation of the swarm is needed to improve the performance of BitTorrent.

Operational Strategies of a Bus-Exclusive Lane Using Barrier Transfer Systems to Control Tidal Traffic Flows (비대칭적 중방향 교통류 대응을 위한 이동식 중앙분리대 활용 버스전용차로 도입 전략 분석)

  • Kim, Taewan;Chung, Younshik;Jeon, Gyo Seok;Kim, Wongil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.2
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    • pp.209-217
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    • 2022
  • Lane management with a central variable lane(s) (or reversible lane) where the traffic flow is temporarily reversed in one or more lanes during peak periods has been evaluated as an effective strategy to alleviate congestion caused by tidal traffic flows. However, due to traffic safety issues, such a movable barrier system can be considered as an alternative to supplement the existing its operation facilities such as static and/or dynamic signs and special pavement markings. In addition, when combined with a bus exclusive lane strategy, its effectiveness could be greatly increased. The objective of this study is to propose a feasibility analysis procedure for operational strategies of a bus-exclusive lanes using a barrier transfer system (BTS) for urban expressways. To this end, a case study was conducted on two urban expressways on the west side of the Han River in Seoul. As a result, temporary operation during rush hour in the morning was found to be most effective. The results presented in this study are expected to serve as a basis for establishing bus-exclusive lane operation strategies using similar systems in the future.

The Photography as Technological Aesthetics (데크놀로지 미학으로서의 사진)

  • Jin, Dong-Sun
    • Journal of Science of Art and Design
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    • v.11
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    • pp.221-249
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    • 2007
  • Today, photography is facing to the crisis of identity and dilemma of ontology from the digital imaging process in the new technology form. It is very important points to say rethinking of the traditional photographic medium, that has changed the way we view the world and ourselves is perhaps an understatement and that photography has transformed our essential understanding of reality. Now, no longer are photographic images regarded as the true automatic recording, innocent evidence and the mirror to the reality. Rather, photography constructs the world for our entertainment, helping to create the comforting illusions by which we live. The recognition that photographs are not constructions and reflections of reality, is the basis for the actual presence within the contemporary photographic world. It is shock. This thesis's aim is to look for the problems of photographic identity and ontological crisis that is controlling and regulating digital photographic imagery, allowing the reproduction of the electronic simulations era. Photography loses its special aesthetic status and becomes no more true information and, exclusively evidence by traditional film and paper that appeared both as a technological accuracy and as a medium-specific aesthetic. The result, photography is facing two crises, one is the photographic ontology(the introduction of computerized digital images) and the other is photographic epistemology(having to do broader changes in ethics, knowledge and culture). Taken together, these crises apparently threaten us with the death of photography, with the 'end' of photography and the culture it sustains. The thesis's meaning is to look into the dilemma of photography's ontology and epistemology, especially, automatical index and digital codes from its origin, meaning, and identity as the technological medium. Thus, in particular, thesis focuses on the analog imagery presence, from the nature in the material world, and the digital imagery presence from the cultural situations in our society. And also thesis's aim is to examine the main issues of the history of photography has been concentrated on the ontological arguments since the discovery of photography in 1839. Photography has never been only one static technology form. Rather, its nearly two centuries of technological development have been marked by numerous, competing of technological innovation and self revolution from the dual aspects. This thesis examines recent account of photography by the analysis of the medium's concept, meaning, identity between film base image and digital base image from the aspects of photographic ontology and epistemology. Thus, the structure of thesis is fairy straightforward to examine what appear to be two opposing view of photographic conditions and ontological situations. Thesis' view contrasts that figure out the value of photography according to its fundamental characteristic as a medium. Also, it seeks a possible solution to the dilemma of photographic ontology through the medium's origin from the early years of the nineteenth century to the raising questions about the different meaning(analog/digital) of photography, now. Finally, this thesis emphasizes and concludes that the photographic ontological crisis reflects to the paradoxical dynamic structure, that unsolved the origins of the medium, itself. Moreover, even photography is not single identity of the photographic ontology, and also can not be understood as having a static identity or singular status from the dynamic field of technologies, practices, and images.

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Evaluating Impact Resistance of Externally Strengthened Steel Fiber Reinforced Concrete Slab with Fiber Reinforced Polymers (섬유 보강재로 외부 보강된 강섬유 보강 콘크리트 슬래브의 충격저항성능 평가)

  • Yoo, Doo-Yeol;Min, Kyung-Hwan;Lee, Jin-Young;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.293-303
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    • 2012
  • Recently, as construction technology improved, concrete structures not only became larger, taller and longer but were able to perform various functions. However, if extreme loads such as impact, blast, and fire are applied to those structures, it would cause severe property damages and human casualties. Especially, the structural responses from extreme loading are totally different than that from quasi-static loading, because large pressure is applied to structures from mass acceleration effect of impact and blast loads. Therefore, the strain rate effect and damage levels should be considered when concrete structure is designed. In this study, the low velocity impact loading test of steel fiber reinforced concrete (SFRC) slabs including 0%~1.5% (by volume) of steel fibers, and strengthened with two types of FRP sheets was performed to develop an impact resistant structural member. From the test results, the maximum impact load, dissipated energy and the number of drop to failure increased, whereas the maximum displacement and support rotation were reduced by strengthening SFRC slab with FRP sheets in tensile zone. The test results showed that the impact resistance of concrete slab can be substantially improved by externally strengthening using FRP sheets. This result can be used in designing of primary facilities exposed to such extreme loads. The dynamic responses of SFRC slab strengthened with FRP sheets under low velocity impact load were also analyzed using LS-DYNA, a finite element analysis program with an explicit time integration scheme. The comparison of test and analytical results showed that they were within 5% of error with respect to maximum displacements.

Corporate Default Prediction Model Using Deep Learning Time Series Algorithm, RNN and LSTM (딥러닝 시계열 알고리즘 적용한 기업부도예측모형 유용성 검증)

  • Cha, Sungjae;Kang, Jungseok
    • Journal of Intelligence and Information Systems
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    • v.24 no.4
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    • pp.1-32
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    • 2018
  • In addition to stakeholders including managers, employees, creditors, and investors of bankrupt companies, corporate defaults have a ripple effect on the local and national economy. Before the Asian financial crisis, the Korean government only analyzed SMEs and tried to improve the forecasting power of a default prediction model, rather than developing various corporate default models. As a result, even large corporations called 'chaebol enterprises' become bankrupt. Even after that, the analysis of past corporate defaults has been focused on specific variables, and when the government restructured immediately after the global financial crisis, they only focused on certain main variables such as 'debt ratio'. A multifaceted study of corporate default prediction models is essential to ensure diverse interests, to avoid situations like the 'Lehman Brothers Case' of the global financial crisis, to avoid total collapse in a single moment. The key variables used in corporate defaults vary over time. This is confirmed by Beaver (1967, 1968) and Altman's (1968) analysis that Deakins'(1972) study shows that the major factors affecting corporate failure have changed. In Grice's (2001) study, the importance of predictive variables was also found through Zmijewski's (1984) and Ohlson's (1980) models. However, the studies that have been carried out in the past use static models. Most of them do not consider the changes that occur in the course of time. Therefore, in order to construct consistent prediction models, it is necessary to compensate the time-dependent bias by means of a time series analysis algorithm reflecting dynamic change. Based on the global financial crisis, which has had a significant impact on Korea, this study is conducted using 10 years of annual corporate data from 2000 to 2009. Data are divided into training data, validation data, and test data respectively, and are divided into 7, 2, and 1 years respectively. In order to construct a consistent bankruptcy model in the flow of time change, we first train a time series deep learning algorithm model using the data before the financial crisis (2000~2006). The parameter tuning of the existing model and the deep learning time series algorithm is conducted with validation data including the financial crisis period (2007~2008). As a result, we construct a model that shows similar pattern to the results of the learning data and shows excellent prediction power. After that, each bankruptcy prediction model is restructured by integrating the learning data and validation data again (2000 ~ 2008), applying the optimal parameters as in the previous validation. Finally, each corporate default prediction model is evaluated and compared using test data (2009) based on the trained models over nine years. Then, the usefulness of the corporate default prediction model based on the deep learning time series algorithm is proved. In addition, by adding the Lasso regression analysis to the existing methods (multiple discriminant analysis, logit model) which select the variables, it is proved that the deep learning time series algorithm model based on the three bundles of variables is useful for robust corporate default prediction. The definition of bankruptcy used is the same as that of Lee (2015). Independent variables include financial information such as financial ratios used in previous studies. Multivariate discriminant analysis, logit model, and Lasso regression model are used to select the optimal variable group. The influence of the Multivariate discriminant analysis model proposed by Altman (1968), the Logit model proposed by Ohlson (1980), the non-time series machine learning algorithms, and the deep learning time series algorithms are compared. In the case of corporate data, there are limitations of 'nonlinear variables', 'multi-collinearity' of variables, and 'lack of data'. While the logit model is nonlinear, the Lasso regression model solves the multi-collinearity problem, and the deep learning time series algorithm using the variable data generation method complements the lack of data. Big Data Technology, a leading technology in the future, is moving from simple human analysis, to automated AI analysis, and finally towards future intertwined AI applications. Although the study of the corporate default prediction model using the time series algorithm is still in its early stages, deep learning algorithm is much faster than regression analysis at corporate default prediction modeling. Also, it is more effective on prediction power. Through the Fourth Industrial Revolution, the current government and other overseas governments are working hard to integrate the system in everyday life of their nation and society. Yet the field of deep learning time series research for the financial industry is still insufficient. This is an initial study on deep learning time series algorithm analysis of corporate defaults. Therefore it is hoped that it will be used as a comparative analysis data for non-specialists who start a study combining financial data and deep learning time series algorithm.