• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2046-2052
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• 2016

Ramp metering is one of the most efficient and widely used control methods for an intelligent transportation management system on a freeway. Its objective is to control and upgrade freeway traffic by regulating the number of vehicles entering the freeway entrance ramp, in such a way that not only the alleviation of the congestion but also the smoothing of the traffic flow around the desired density level can be achieved for the maintenance of the maximum mainline throughput. When the cycle of the signal detection is larger than that of the system process, the density tracking problem needs to be considered in the form of the discrete-time system. Therefore, a discrete-time sliding mode control method is proposed for the ramp metering problem in the presence of both input constraint in the on-ramp and exogenous disturbance in the off-ramp considering the random behavior of the driver. Simulations were performed using a validated second-order macroscopic traffic flow model in Matlab environment and the simulation results indicate that proposed control method can achieve better performance than previously well-known ALINEA strategy in the sense that mainstream flow throughput is maximized and congestion is alleviated even in the presence of input constraint and exogenous disturbance.

• Journal of Engineering Education Research
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• v.20 no.5
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• pp.34-42
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• 2017

This study aimed to identify the causal relationships among self-regulated learning strategy, problem solving efficacy, task value and learning outcome, and mediation effect of self-regulated learning strategy in engineering capstone design course. The data were collected from 363 university students who enrolled in capstone design courses and analyzed using structural equation modeling method. The results were: first, problem-solving efficacy and task value exerted significant effects on self-regulated learning strategy. Second, self-regulated learning strategy exerted significant effects on learning outcome, but problem-solving efficacy and task value did not. Third, problem-solving efficacy and task value showed significant indirect effects on learning outcome, which confirmed that self-regulated learning strategy fully mediated between two exogenous variables and learning outcome.

• Journal of the Korean Home Economics Association
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• v.48 no.8
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• pp.13-26
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• 2010

This study tested the path model with regard to how certain variables (control attribution, demand-control-support of activity, and control strategy) affected the elderly workers' subjective well-being(swb). In the path model, the exogenous variables were internal and external control attribution. We used demand-control-support of activity, and primary and secondary control strategies as mediating variables. The endogenous variable was each elderly worker's swb. Study participants were 205 elders participating in an "education activity". We used descriptive statistical analysis, Pearson's correlation and hierarchical multiple regression to examine data collected from structured interviews with the participants. Path analysis revealed the followings: First, secondary control strategy was the strongest predictor of participants' swb but internal control attribution, demand of activity, and support of activity also positively affected participants' swb. Second, internal control attribution indirectly affected the participants' swb. Finally primary control strategy negatively affected on the participants' swb.

• Toxicological Research
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• v.34 no.4
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• pp.297-302
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• 2018

Cells are constantly exposed to endogenous and exogenous chemical and physical agents that damage their genome by forming DNA lesions. These lesions interfere with the normal functions of DNA such as transcription and replication, and need to be either repaired or tolerated. DNA lesions are accurately removed via various repair pathways. In contrast, tolerance mechanisms do not remove lesions but only allow replication to proceed despite the presence of unrepaired lesions. Cells possess two major tolerance strategies, namely translesion synthesis (TLS), which is an error-prone strategy and an accurate strategy based on homologous recombination (homology-dependent gap repair [HDGR]). Thus, the mutation frequency reflects the relative extent to which the two tolerance pathways operate in vivo. In the present paper, we review the present understanding of the mechanisms of TLS and HDGR and propose a novel and comprehensive view of the way both strategies interact and are regulated in vivo.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.2
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• pp.61-66
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• 2005

This paper presents an unified method which solves real and reactive power dispatch problems for the economic operation of power systems using evolutionary computation such as genetic algorithms(GA), evolutionary programming(EP), and evolution strategy(ES). Many conventional methods to this problem have been proposed in the past, but most of these approaches have the common defect of being caught to a local minimum solution. The proposed methods, applied to the IEEE 30-bus system, were run for 10 other exogenous parameters and composed of P-optimization module and Q-optimization module. Each simulation result, by which evolutionary computations are compared and analyzed, shows the possibility of applications of evolutionary computation to large scale power systems.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.3
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• pp.472-491
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• 2013

This research addressed limits to promoting SMEs networking programs, especially with universities, in the context of national and regional policies for urban economic development, centering on the case of Daegu City. In large cities such as Daegu City, the strategy focusing on promoting SMEs networking activities, utilizing the advantages of urban economy, is likely to be necessary for urban economic development in knowledge-based economy. However, national and regional policy direction for urban economic development relied on exogenous strategies attracting firms, and regional S&T policies focused on universities and research institutes rather than SMEs, being strongly initiated by central government. Thus, to promote policies supporting local SMEs networking in Daegu City was seen as being difficult. Under these circumstances, region-specific policies related to support networking activities of SMEs might be dealt with neglectedly.

• Journal of Life Science
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• v.27 no.8
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• pp.945-950
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• 2017

To some extent, the growth of solvent-tolerant Pseudomonas sp. BCNU 106 is limited by toxic solvents. Therefore, various strategies to overcome this limitation need to be investigated. One such strategy is to use exogenous trehalose. The highest intracellular trehalose content of 181.88 mM was measured at 12 hr. The extracellular trehalose content decreased rapidly within 12 to 16 hr in the presence of cyclohexane. Moreover, the number of Pseudomonas sp. BCNU 106 cells grown in Luria-Bertani (LB) broth supplemented with 0.1 M trehalose in the presence of 1%(v/v) cyclohexane, hexane, propylbenzene, and m-xylene increased 89.94-, 89.72-, 91.25-, and 118.9-fold, respectively, in comparison to the control level. High survival rates of 80% and 90% were observed in the presence of cyclohexane and hexane by the addition of 0.05 M trehalose for up to 4 hr, respectively. Exogenously-added trehalose was transported into the cells, and it conferred protection against cyclohexane, hexane, propylbenzene, and m-xylene. Adding exogenous trehalose to the growth medium improved the tolerance of Pseudomonas sp. BCNU 106; thus, it is a potential biocatalyst for biotransformation and biodegradation.

• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.71-85
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• 1985

The study attempts to explore factors which affect life satisfaction of the elderly, and thereby to identify the most efficient strategy to enhance their happiness and satisfaction with life by means of a family support system. Previous research suggests that the family is the main origin from which emotional and ecionomic satisfacton of the aged evolves, and satisfaction is facilitated by societal assistance for the family to financially support old persons. These theoretical antecedents are incorporated into a causal model for empirical verificatio. To this end, interviews were conducted in Seoul with 300 individuals who are 60 years old or over. The major findings of this study support the theoretical assertions of previous studies. They are summarized as follows : 1. Family solidarity is highly correlated with life satisfaction of the elderly. 2. Family solidarity is raised by the intensity of their social association, satisfaction with housing, and financial resources. 3. Eduation, income and marital status as exogenous variables do not directly affect life satisfaction and family solidarity, despite their strong overall correlation. Casual effects of each variable are linked to family solidarity and then to life satisfaction through a family support system for the elderly.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.166-168
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• 1996

This paper presents an power system optimization method which solves real and reactive power dispatch problems using evolutionary computation such as genetic algorithms(GAs), evolutionary programming(EP), and evolution strategy(ES). Many conventional methods to this problem have been proposed in the past, but most these approaches have the common defect of being caught to a local minimum solution. Recently, global search methods such as GAs, EP, and ES are introduced. The proposed methods, applied to the IEEE 30-bus system, were run for 12 other exogenous parameters. Each simulation result, by which evolutionary computations are compared and analyzed, shows the possibility of applications of evolutionary computation to large scale power systems.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.29-43
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• 2013

The dominant perspective on institutional change of the GRI is the environment-dependence. GRI's institutions are, however, prone to change due to the endogenous factors. Therefore, we need a dynamic alternative model to analyze the interaction between the exogenous and endogenous factors around the GRI's institutions. In this paper, authors examined the changes in GRI's funding system. The results were verified in the layering which is a one of the dynamic institutional change forms. Owing to the interaction between the exogenous and endogenous factors, institutional reform's layers of the institution funding expansion have been continuously accumulated in order to modify the Project-Based System(PBS). Eventually expansion layers of the institution funding have grown more quickly than the Project-Based System(PBS), as a result, GRI's funding system has been changing centered on the Block funding.