• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.806-807
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• 2007

Systematic studies on the dispatch scheduling algorithm and related constraints can enhance the effectiveness of electricity market operation. When System Operator (SO) establishes a dispatch schedule, the bid information should be preserved in the schedule as much as possible. In this paper, we introduce a new type of sensitivity factor called Line Outage Impact Factor (LOIF) to screen a transmission line causing the most severe outage when scheduling the dispatch. This screening can assure the stable system operation and make an efficient feedback between the SO and market participants. We propose a transmission line contingency constrained Pre-dispatch algorithm using sensitivity indices in a suitable Pre-dispatch scheduling. The proposed algorithm has been tested on sample system and the results show more secure operation against critical contingencies.

• The Journal of Korean Association of Computer Education
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• v.15 no.1
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• pp.43-53
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• 2012

The spread of smartphones, many educational applications have been developed. However, the existing educational applications, learning the simple and uniform, due to the way the needs of learners are given feedback after learning did not reflect the present problem is how. In this paper vocabulary learning applications to implement the existing application using the learners' needs, survey analysis, and analysis results to reflect the learner's motivation to continue the learners to self-built learning objectives according to the stages of learning tailored to the training schedule set up and made a systematic feedback learning vocabulary was designed and implemented applications.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.81-87
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• 2006

A new gain-scheduled control design is proposed to improve disturbance attenuation for systems with bounded control input. The state feedback controller is scheduled according to the proximity to the origin of the state of the plant. The controllers is derived in the framework of linear matrix inequality(LMI) optimization. This procedure yields a linear time varying control structure that allows higher gain and hence higher performance controllers as the state move closer to the origin. The main results give sufficient conditions for the satisfaction of a parameter-dependent performance measure, without violating the bounded control input condition.

• Journal of Convergence Society for SMB
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• v.3 no.1
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• pp.7-13
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• 2013

It will prove that with a more plausible specification of the relationship between income and the value of leisure, we can develop a more accurate model of the labor market without necessarily losing the primary merit of the received model. Moreover, with an improved understanding of labor market dynamic we can see that progressive era labor market legislation, designed to mitigate the effects of bargaining power inequality in low wage labor markets, was in fact based upon sensible economic foundations. The results of this study as follow; These low-wage dynamics present an example of a positive feedback system or "vicious circle" at work in the economy. With the revised labor supply schedule presented above, the market dynamic of the low wage sector push the wage away from the range that is consistent with a self-regulating market.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.359-366
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• 2013

Although many research efforts have been conducted to address the effect of crew members' work skills (e.g., technical and planning skills) on work performance (e.g., work duration and quality) in construction projects, the relationship between skill and performance has generated a great deal of controversy in the field of management (Inkpen and Crossan 1995). This controversy can lead to under- or over-estimations of the overall project schedule, and can make it difficult for project managers to implement appropriate managerial policies for enhancing project performance. To address this issue, the following aspects need to be considered: (a) work performances are determined not only by individual-level work skill but also by the group-level work skill affected by work team members, each member's role, and any working behavior pattern; (b) work planning has significant effects on to what extent work skill enhances performance; and (c) different types of activities in construction require different types of work, skill, and team composition. This research, therefore, develops a system dynamics (SD) model to analyze the effects of both individual-and group-level (i.e., multi-level) skill on performances by utilizing the advantages of SD in capturing a feedback process and state changes, especially in human factors (e.g., attitude, ability, and behavior). The model incorporates: (a) a multi-level skill evolution and relevant behavior development mechanism within a work group; (b) the interaction among work planning, a crew's skill-learning, skill manifestation, and performances; and (c) the different work characteristics of each activity. This model can be utilized to implement appropriate work planning (e.g., work scope and work schedule) and crew management policies (e.g., work team composition and decision of each worker's role) with an awareness of crew's skill and work performance. Understanding the different characteristics of each activity can also support project managers in applying strategic work planning and crew management for a corresponding activity, which may enhance each activity's performance, as well as the overall project performance.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.219-231
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• 2005

Many applications in cluster computing require QoS (Quality of Service) services. Since performance predictability is essential to provide QoS service, underlying systems must provide predictable performance guarantees. One way to ensure such guarantees from network subsystems is to generate global schedules from applications'network requests and to execute the local portion of the schedules at each network interface. To ensure accurate execution of the schedules, it is essential that a global time base must be maintained by local clocks at each network interface. The task of providing a single time base is called a synchronization problem and this paper addresses the problem for system area networks. To solve the synchronization problem, FM-QoS (1) proposed a simple synchronization mechanism called FBS(Feedback-Based Synchronization) which uses built-in How control signals. This paper extends the basic notion of FM-QoS to a theoretical framework and generalizes it: 1) to identify a set of built-in network flow control signals for synchrony and to formalize it as a synchronizing schedule, and 2) to analyze the synchronization precision of FBS in terms of flow control parameters. Based on generalization, two application classes are studied for a single switch network and a multiple switch network. For each class, a synchroniring schedule is proposed and its bounded skew is analyzed. Unlike FM-QoS, the synchronizing schedule is proven to minimize the bounded skew value for a single switch network. To understand the analysis results in practical networks, skew values are obtained with flow control parameters of Myrinet-1280/SAN. We observed that the maximum bounded skew of FBS is 9.2 Usec or less over all our experiments. Based on this result, we came to a conclusion that FBS was a feasible synchronization mechanism in system area networks.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.282-288
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• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we found that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1951-1956
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• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we find that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• Journal of Korean Academy of Nursing
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• v.35 no.6
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• pp.1113-1124
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• 2005

Purpose: The purpose of this study was to develop an e-Learning program about medication for nurses to enhance nurses' medication performance ability and to analyze learners' responses after studying with this program. Method: For the development of the e-Learning program, the NBISD(Network Based Instructional Systems Design) model, suggested by Jung(I999) was applied as a basic model and the instruction design theory of Gagne & Briggs(1979) and ARCS theory of Keller(I983) were applied. After the operation of this program for one month to 34 new nurses, learners' responses were analyzed. Result: Learners' knowledge of medication was greatly improved after this program. In addition learners' satisfaction with the overall education program, help in field applicability, ease of screen shift and exploration, and tutor activities were high and the contents were regarded suitable for e-Learning. Many things were advantageous such as easy accessibility, easy understandability with pictures and flash animation, practical cases and feedback from a tutor. Provision of a supplementary handout and improvement of a tight time schedule were pointed out as things to be improved. Conclusion: This e-Learning program can be used effectively for medication education for registered nurses, student nurses, and new nurses.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.78-83
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• 2011

Traditional autopilot design requires an accurate aerodynamic model and relies on a gain schedule to account for system nonlinearities. This paper presents the control architecture applied to a dynamic model inversion at a single flight condition with an on-line neural network (NN) in order to regulate errors caused by approximate inversion. This eliminates the need for an extensive design process and accurate aerodynamic data. The simulation results using a developed full nonlinear 6 degree of freedom model are presented. This paper also presents the stability evaluation for control systems to which NNs were applied. Although feedback can accommodate uncertainty to meet system performance specifications, uncertainty can also affect the stability of the control system. The importance of robustness has long been recognized and stability margins were developed to quantify it. However, the traditional stability margin techniques based on linear control theory can not be applied to control systems upon which a representative non-linear control method, such as NNs, has been applied. This paper presents an alternative stability margin technique for NNs applied to control systems based on the system responses to an inserted gain multiplier or time delay element.