• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.775-779
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• 2011

As the technology of multimedia sensor networks is desired in large numbers of applications nowadays, real-time service becomes one of the most important research challenges. Even though lots of related works have been conducted to meet this requirement in several ways, the specific traffic model for real-time has not been taken yet. Thus, it causes lack of adaptability of those approaches in real deployment. To solve this problem, in this paper, we model the application via (m,k)-firm streams which have weakly hard real-time property. And then, a novel forwarding scheme based on modified DBP (Distance-Based Priority) is proposed by considering local-DBP and stream DBP together. Local-DBP can contribute to identify the detailed causes of unsatisfied quality, that is, network congestion or wireless link failure. Simulation results reveal that (m,k)-firm is a good traffic model for multimedia sensor networks and the proposed scheme can contribute to guarantee real-time requirement well.

• Journal of Power Electronics
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• 제14권1호
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• pp.156-164
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• 2014

The power-voltage (P-V) characteristic of a photovoltaic (PV) array is nonlinear and time varying with the change in atmospheric conditions. As a result, the maximum power point tracking (MPPT) technique must be applied in PV systems to maximize the generated energy. The incremental conductance (INC) algorithm, one of the MPPT strategies, is widely used for its high tracking accuracy, good adaptability to rapidly changing atmospheric conditions, and easy implementation. This paper presents a modified asymmetrical variable step size INC MPPT method that is based on the asymmetrical feature of the P-V curve. Compared with conventional fixed or variable step size method, the proposed method can effectively improve tracking accuracy and speed. The theoretical foundation and design principle of the proposed approach are validated by the simulation and experimental results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.159-162
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• 2005

Random Early Detection (RED), one of the most well-known Active Queue Management (AQM), has been designed to substitute Tail Drop and is nowadays widely implemented in commercially available routers. RED algorithm provides high throughput and low delay as well as a solution of global synchronization. However RED is sensitive to parameters setting, so the performance of RED, significantly depends on the fixed parameters. To solve this problem, the Adaptive RED (ARED) algorithm is suggested by S. Floyd. But, ARED also uses fixed parameters like target-queue length; it is hard to respond to bursty traffic actively. In this paper, we proposed AQM algorithm based on the variation of current queue length in order to improve adaptability about burst traffic. We measured performance of proposed algorithm through a throughput, marking-drop rate and bias phenomenon. In experimentation, we raised a packet throughput as reduced packet drop rate, and we confirmed to reduce a bias phenomenon about bursty traffic.

• 한국정보교육학회:학술대회논문집
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• 한국정보교육학회 2007년도 하계학술대회
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• pp.129-134
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• 2007

학교 현장에서의 컴퓨터 교육은 여전히 시범실습위주로 이루어지고 있으며. 초등학교 컴퓨터 교육에서 많은 비중을 차지하는 소프트웨어 교육은 더욱 그러하다. 소프트웨어는 끊임없이 개발되거나 업그레이드 되고 있어 가르쳐야 할 내용이 많아져 새로운 학습방법이 필요하다. 즉 문제사태에서 필요한 기능을 찾아 스스로 문제를 해결하고 다른 응용소프트웨어에 전이 및 파지할 수 있는 능력을 길러주는 학습방법이 필요하다. 그 방법 중의 하나가 구성주의 학습 원리에 부합한 문제중심학습이며 학습의 효과를 높이기 위해서 온라인과 오프라인학습의 장점을 혼합한 B-러닝 방법이 필요하다. 따라서 본 연구는 응용소프트웨어의 적응력을 향상시키기 위해 한글 워드프로세서 학습내용을 학습자의 수준에 맞게 문제중심으로 재구성하고 온라인 학습을 위해 학급커뮤니티를 설계 및 구현하였다. 그리고 문제중심의 B-러닝에 적합한 학습모형을 설계하여 제시하였다. 문제중심의 B-러닝은 구성주의 학습 원리에 적합한 실생활의 문제를 학습내용으로 하고 면대면 교실수업의 장점과 온라인 학습의 장점을 혼합하여 자기주도적으로 탐구학습을 하는 것이므로 응용소프트웨어의 적응력은 향상될 것으로 기대한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.31-34
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• 1991

This paper presents a voltage-reactive power control algorithm considering fuzziness. In this paper, a coordination technique based on fuzzy set theory is applied for system loss-voltage compromises. Here, we introduce membership functions to measure the adaptability of real power loss of transmission line and the deviation of load bus voltage from the constraints. Then the optimization of problem is solved by a linear programming technique considering the fuzzy set theory. The objective is a degree of satisfaction about the fuzzy decision-making function. The effectiveness of this algorithm has been verified by testing on sample systems.

• Journal of Mechanical Science and Technology
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• 제15권5호
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• pp.544-554
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• 2001

A shop floor can be considered as an important level to develop Computer Integrated Manufacturing system (CIMs). However, a shop floor is a dynamic environment where unexpected events continuously occur, and impose changes to the planned activities. To deal with this problem, a shop floor should adopt an appropriate control system that is responsible for the coordination and control of the manufacturing physical flow and information flow. In this paper, a hybrid control system is described with a shop floor activity methodology called Multi-Layered Task Initiation Diagram (MTD). The architecture of the control model contains three levels: i.e., he shop floor controller (SFC), the intelligent agent controller (IAC) and the equipment controller (EC). The methodology behind the development of the control system is an intelligent multi-agent paradigm that enables the shop floor control system to be an independent, an autonomous, and distributed system, and to achieve an adaptability to change of the manufacturing environment.

• 산업공학
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• 제20권3호
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• pp.407-417
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• 2007

Owing to a real-time innovative infrastructure driven by destructive technology revolution, the business environment has been changed dramatically. In order to respond fast to a continuously and unpredictably changing business environment, the business entities, such as business process participants, customers, distributers, and partners, should have an agile paradigm which is able to acquire and share the real time information adaptively. As a 21st century business paradigm having such adaptability and responsiveness has been introduced and called the "Real-Time Enterprise (RTE)" strategy. In this paper, we investigate the various innovation cases adopting the RTE strategy. After briefly addressing the concept and the value of RTE strategy, we discuss the models and the frameworks used in outstanding international and domestic enterprises. We believe that this case study can provide a good guide to many enterprises planning to adopt a RTE strategy for building competitive advantage in today's world of global competition.

• 전기학회논문지
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• 제67권5호
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• pp.663-668
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• 2018

A combined CPG (Central Pattern Generator) based foot trajectory and GA (Genetic Algorithm) based joint compensation method is presented for adaptive humanoid walking. In order to increase an adaptability of humanoid walking for rough terrains, the experiment for rolling terrains are introduced. The CPG based foot trajectory method has been successfully applied to basic slops and variable slops, but has a limitation for the rolling terrains. The experiments are conducted in an ODE based Webots simulation environment using humanoid robot Nao to verify a stability of walking for various rolling terrains. The proposed method is compared to the previous CPG foot trajectory technique and shows better performance especially for the cascade rolling terrains.

• 한국생활과학회지
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• 제13권5호
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• pp.691-699
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• 2004

The purpose of this study was to analyze the relationship between family functioning and family violence. The SPSS 10.0 for Windows was used to analyze data obtained through 1,044 children who live in Gwangju Chonnam area. Major findings are as follows: 1. Wife abuse and child abuse showed significant difference according to family cohesion, family flexibility, and family-system types. 2. In family violence non-experience group, 'balanced family' was found in 36.2% of the sample and 'extreme family' in 7.8%. In family violence experience group, 'balanced family' was found in 12.7% of the sample and 'extreme family' in 15.4%. 3. There were significant negative correlations between family functioning and family violence. Family cohesion and family flexibility had significant negative correlation with wife abuse and child abuse.

• 한국생활과학회지
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• 제16권2호
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• pp.251-257
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• 2007

The combined impact of maternal depression, parenting stress, infant cry, and infant temperament on family functions was examined. The sample included 257 mothers in the near communities. Questionnaires completed by the mothers who had 0-36 month old children were used to measure depressive symptoms in mothers, infant cry, infant temperament, parenting stress, and family function. Maternal depression, parenting stress, infant crying and infant temperament had negative influence on family adaptability and family cohesion. Mother's depression had negative effect particularly on infant cry. Infant cry had positive effect on infant temperament. Infant temperament had high direct effect on parenting stress. As a result, it had negative influence on family function.