• 대한전기학회논문지:시스템및제어부문D
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• 제53권9호
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• pp.622-629
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• 2004

In practical control systems, the capacity of actuators is limited and this degrades the system performances and it is often a source of instability. To use full capacity of actuators, we adopt the gain scheduled control permitting the over saturation in controls. The basic idea of gain scheduled control is to use a higher gain control when the state variables are smaller and a lower gain control when the state variables are larger. First, we derive a constant H control and a reachable set while satisfying the degree of over saturation. Next, we divide this set into nested subsets and find $H_{\infty}$ controls at rack subsets while satisfying the degree of over saturation. Finally, the control gain is applied according to the status of states. Note that all procedures are done by solving linear matrix inequalities(LMI). Finally, we show the validity and applicability of our proposed control using the simulations of a six-story building subjected to the earthquake excitation.

• 한국농공학회지
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• 제44권7호
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• pp.36-45
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• 2002

Most of rural bridges have passed 30 years of age since they were built, which have to support unexpected overload caused by changed design load and excessive amount of transportation. For these rural bridges, repairs and replacements are needed. Even though there have been attempt to estimate the safety of existing bridges deteriorated with major defects, those approaches must rely on the observable damage and subsequent decisions are made subjectively. To avoid the high cost of rehabilitation, the bridge rating must correctly represent the present load-carrying capacity. Rating engineers use a methods such as Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance method is suggested instead of the bridge replacement.

• STI Policy Review
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• 제2권1호
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• pp.55-73
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• 2011

Intermediaries are presenting not only transactional information that orchestrates electronic transaction, but also market related information and knowledge useful for sellers' understanding of the market status. However, we do not have strong evidence that the market related information and knowledge is properly utilized by sellers and that it has an actual influence on sellers' performance. According to the research result, absorptive capacity and the pattern of information system utilization is statistically significant to sellers' performance mediated by operational efficiency and market knowledge creation. Especially, explorative utilization of information system and realized absorptive capacity has a stronger influence on sellers' performance mediated by market knowledge creation. With this research result, this study maintains that sellers are required to absorb and utilize market related information and knowledge more actively through explorative utilization of information system to achieve better performance in the e-marketplace. On the other hand, intermediaries are recommended to provide abundant and valuable market related information and knowledge for the sellers to build up better e-marketplaces.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.353-365
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• 2020

In the previous studies, the authors proposed the use of laminated veneer lumber - carbon fiber reinforced polymer (LVL-CFRP) composite beams for structural application. Bond strength of the LVL-to-CFRP interface and flexural strengthening schemes to increase the bending capacity subjected to positive and negative moment were discussed in the previous works. In this article, theoretical models are proposed to predict the moment capacity when the LVL-CFRP beams are subjected to negative moment. Two common failure modes - CFRP fracture and debonding of CFRP are considered. The non-linear model proposed for positive moment is modified for negative moment to determine the section moment capacity. For the debonding based failure, previously developed bond strength model for CFRP-to-LVL interface is implemented. The theoretical models are validated against the experimental results and then use to determine the moment-rotation behaviour and rotational rigidity to compare the efficacy of various strengthening techniques. It is found that combined use of bi- and uni-directional CFRP U-wrap at the joint performs well in terms of both moment capacity and rotational rigidity.

• 지식경영연구
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• 제16권2호
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• pp.139-172
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• 2015

Employee's agility is becoming a primary factor of improving individual work performance. Employee's agility refers to responsiveness or behavior of employees in the context of work environment change. The purpose of this study is to examine the relationship between employee's agility and work performance in the perspective of agility's influence factors(absorptive capacity, IT resource use, readiness to change) and knowledge-oriented leadership, A survey was conducted for gathering data (a total of 262 employees from 35 industrial organizations) to test the relationships. The results of analysis show that employee's agility is a driving force leading to individual work performance, that employee's absorptive capacity, IT resource use, readiness to change, and knowledge-oriented leadership are the significant influential factors of employee's agility, and that knowledge-oriented leadership strengthens the link between employee's absorptive capacity and agility. For theoretical and practical contributions, the research presents the grounds for arguments that employee's agility is employee's dynamic capability for individual work performance under work environment change, and that organizations trying to improve employee's agility need to explore employee's behavioral attitudes under individual, leader, and organizational dimensions. Limitations arisen in the course of the research and suggestions for future research directions are also discussed.

• 산업공학
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• 제16권2호
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• pp.195-200
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• 2003

In this paper, the selective use of RTS and CTS frames is considered to analyze the capacity of IEEE 802.11 WLAN (Wireless Local Area Network). The RTS and CTS frames are used to transmit the data frames longer than dot11RTSThreshold according to IEEE 802.11 specification. The analysis of the optimal RTS-CTS threshold is derived to maximize the capacity of IEEE 802.11 WLAN. And, numerical examples are also presented for IEEE 802.11 a and b WLANs.

• 대한가정학회지
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• 제25권1호
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• pp.121-127
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• 1987

The purpose of this study was to investigate the importance of mental capacity and to see whether it can be a barometer to predict childrne's cognitive development. The instruments used were Pictoral Test of Intelligence to select homogeneous samples, Cucui Scale for their M-power and Conservation Test. The results showed that M-power develops as age increases, and it can be a strong variable to predict their cognitive development. It has been demonstrated that capacity increases developmentally but whether this reflects changes in capacity perse, or in the efficient use of that capacity is a debatable issue. More study needs to be repeated for this matter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.72-79
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• 2001

In this paper we present a nonlinear programming model for the solution of the train seat capacity distribution problem (TSCDP) with a numerical example. The TSCDP model finds the optimal capacity distribution methods which minimize the sum of the differences between the demands and the seat capacities. Also the TSCDP provides the information on the degree of the discrepancy between the demand and the seat capacities. One can use the TSCDP model as a tool for planning train seat capacity planning.

• Computational Structural Engineering : An International Journal
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• 제3권1호
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• pp.49-59
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• 2003

This paper discusses the enhancement of the buckling capacity of column strips by use of piezoelectric layer. The analytical model for obtaining the buckling capacity of the piezoelectric coupled column with general boundary conditions modelled with different types of springs applied at the ends of the column is derived the first time. Based on this proposed model, the buckling capacity of the column strips can be accurately predicted by solving an eigenvalue problem. The computational results show the great potential of the piezoelectric materials in enhancing the buckling capacity of the column strips. The optimal locations of the piezoelectric layer for higher buckling capacity are also obtained for the columns with. standard pinned-pinned, fixed-free, and fixed-pinned structures. In addition, the buckling capacity and the increase of buckling capacity are discussed for those columns with the general boundaries as well. This research may provide a benchmark for the buckling analysis of the piezoelectric coupled strips.

• Geomechanics and Engineering
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• 제3권2호
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• pp.153-167
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• 2011

Traditional design methods of bearing capacity of shallow foundations are deterministic in the sense that they do not explicitly consider the inherent uncertainty associated with the factors affecting bearing capacity. To account for such uncertainty, available deterministic methods rather employ a fixed global factor of safety that may lead to inappropriate bearing capacity predictions. An alternative stochastic approach is essential to provide a more rational estimation of bearing capacity. In this paper, the likely distribution of predicted bearing capacity of strip footings subjected to vertical loads is obtained using a stochastic approach based on the Monte Carlo simulation. The approach accounts for the uncertainty associated with the soil shear strength parameters: cohesion, c, and friction angle, ${\phi}$, and the cross correlation between c and ${\phi}$. A set of stochastic design charts that assure target reliability levels of 90% and 95%, are developed for routine use by practitioners. The charts negate the need for a factor of safety and provide a more reliable indication of what the actual bearing capacity might be.