• 전기학회논문지
• /
• 제65권12호
• /
• pp.2046-2052
• /
• 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.

• 공학교육연구
• /
• 제20권5호
• /
• pp.34-42
• /
• 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.

• 대한가정학회지
• /
• 제48권8호
• /
• pp.13-26
• /
• 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
• /
• 제34권4호
• /
• pp.297-302
• /
• 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.

• 전기학회논문지P
• /
• 제54권2호
• /
• pp.61-66
• /
• 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.

• 한국경제지리학회지
• /
• 제16권3호
• /
• pp.472-491
• /
• 2013

본 연구는 도시경제발전을 위한 국가 및 지방정책의 맥락에서 중소기업 네트워킹 정책을 활성화시키는 데 있어서의 한계점들을 대구지역의 사례를 중심으로 살펴보았다. 대구시와 같은 대도시에서는 도시경제의 이점을 활용하여 중소기업의 네트워킹 활동을 촉진시키는 전략은 지식기반경제에서 도시경제발전을 위해 필요한 것으로 보인다. 하지만, 기업유치라는 외생적 전략에 의존하는 국가 및 지방의 정책방향과 함께 지방과학기술정책이 중앙정부 주도로 추진되면서 중소기업보다는 대학과 연구소 중심으로 진행되고 있기 때문에 중소기업의 네트워킹 활동을 지원하는 정책을 제고하는 것은 어려운 것으로 보인다. 이러한 환경에서는 중소기업 네트워킹 활동 지원과 관련된 지역 특화 정책들은 소홀하게 다루어질 가능성이 높다.

• 생명과학회지
• /
• 제27권8호
• /
• pp.945-950
• /
• 2017

유기용매 내성 Pseudomonas sp. BCNU 106은 독성 용매에 의해 일부 생장이 제한되므로 다양한 생존전략이 필요하다. 이러한 한계를 극복하기 위한 하나의 전략으로 외인성 트레할로오스를 사용하는 것이다. Cyclohexane 존재하에 세포내 트레할로스 함량은 12시간 배양했을 때 181.88 mM로 가장 높게 측정되었고, 세포외 트레할로스 함량은 12시간에서 16시간 사이에 급격하게 감소하였다. 또한 1%(v/v) cyclohexane, hexane, propylbenzene 및 m-xylene 존재하에 0.1 M 트레할로스가 첨가된 LB 배지에서 Pseudomonas sp. BCNU 106 균주의 생장은 트레할로스가 첨가되지 않은 대조군에 비해 각각 89.94, 89.72, 91.25 및 118.9 배 증가하였으며, cyclohexane 및 hexane 존재하에서 0.05 M 트레할로스를 첨가했을 때 4시간 동안 각각 80과 90% 이상의 높은 생존율을 보였다. 이는 배지에 첨가된 트레할로스가 세포 내로 이동하면서 cyclohexane, hexane, propylbenzene 및 m-xylene 스트레스에 대해 방어작용을 한 것으로 보인다. 따라서 성장배지에 트레할로스를 첨가함에 따라 Pseudomonas sp. BCNU 106의 유기용매 내성이 향상되어 생물전환 및 생물분해에 대한 잠재적인 생물촉매로 사용 가능할 것이다.

• 대한가정학회지
• /
• 제23권1호
• /
• pp.71-85
• /
• 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.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.166-168
• /
• 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.

• 디지털융복합연구
• /
• 제11권9호
• /
• pp.29-43
• /
• 2013

출연연 제도변화에 대한 지배적인 관점은 환경 정책변화라는 외부적인 환경의 요구사항에 기능적으로 대응하기 위해 변화한다는 기능론적 입장이다. 하지만 출연연 제도는 내부적 요인으로 인해 변화가 발생하기도 한다. 따라서 출연연 제도변화를 분석에 있어서 외부적 요인과 내부적 요인이 상호작용해서 변화가 발생한다는 동태적인 대안적 모형이 필요하다. 본 논문에서는 출연연 예산제도가 연구과제중심제도(PBS 모델)에서 묶음예산 모델로 변화하는 과정을 살펴보았는데, 변화과정이 동태적 제도변화 양식 중에 층화(layering)에 해당함을 확인하였다. 즉 외부적 요인과 내부적 요인이 상호작용해서 PBS 모델을 수정하기 위해 정부출연금 확대라는 제도개선의 층을 지속적으로 누적시켰다. 결국 안정적 연구환경 조성 및 연구전념을 위해 지속적으로 누적된 정부출연금 확대라는 제도개선의 층은 정치적 계기를 맞아 단계적으로 빠르게 성장함으로서 묶음예산 모델로 변화되는 동태적인 과정을 확인하였다.