• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.33 no.6
• /
• pp.241-246
• /
• 1984

The power system scheduling process is formulated as an optimization problem with linear inequality constraints. AC Loadflow method is used for the problem solution and line losses are considered. The constraints under consiceration are generator power limits, load schedding limits and line capacity limits. In solving the objective function the Dual Relaxation method is adopted. Tests indicate that the method is practical for real time applications.

• Journal of Korea Technology Innovation Society
• /
• v.9 no.2
• /
• pp.199-235
• /
• 2006

Research interest in TQM has recently begun extending beyond manufacturing to moreinnovative R&D activities. Despite numerous studies of the relationship between TQM and organizational performance, little are known about the relationship between TQM and R&D performance. This is especially true for manufacturing-based R&D performance. The objective of this study is to examine the relationship between TQM and R&D, and also explore several contingencies that moderate the relationship. The study uses data from 133 R&D divisions of Korean manufacturing firms to test hypotheses regarding the relation of TQM with R&D. TQM measures are aligned with the six criteria of Malcolm Baldrige National Quality Award, and the R&D performance measures consist of incremental and innovative R&D aspects. The findings from structural equation modeling show that TQM practices contribute to R&D performance significantly in aggregate, and their specific contributions vary according to the contingencies, which provide further understanding of the relationship between TQM and R&D in the manufacturing sector. Therefore, the results could offer firms a better strategy for their R&D management. This study is, however, exploratory in nature; the conclusion is tentative and may thus be different in other research settings.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.3
• /
• pp.1083-1089
• /
• 2015

Background: Compliance with California's smoke-free restaurant and bar policies may be more a function of social contingencies and less a function of legal contingencies. The aims of this study were: 1) to report indications of compliance with smoke-free legislation in Korean bars and restaurants in California; 2) to examine the demographic, smoking status, and acculturation factors of who smoked indoors; and 3) to report social cues in opposition to smoking among a sample of Koreans in California. Materials and Methods: Data were collected by telephone surveys administered by bilingual interviewers between 2007-2009, and included California adults of Korean descent who visited a Korean bar or restaurant in a typical month (N=2,173, 55% female). Results: 1% of restaurant-going participants smoked inside while 7% observed someone else smoke inside a Korean restaurant. Some 23% of bar-going participants smoked inside and 65% observed someone else smoke inside a Korean bar. Presence of ashtrays was related to indoor smoking in bars and restaurants. Among participants who observed smoking, a higher percentage observed someone ask a smoker to stop (17.6%) or gesture to a smoker (27.0%) inside Korean restaurants (N=169) than inside Korean bars (n=141, 17.0% observed verbal cue and 22.7% observed gesture). Participants who smoked inside were significantly younger and more acculturated than participants who did not. Less acculturated participants were significantly more to likely to be told to stop smoking. Conclusions: Ten years after implementation of ordinances, smoking appears to be common in Korean bars in California.

• KIEE International Transactions on Power Engineering
• /
• v.11A no.4
• /
• pp.15-20
• /
• 2001

Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison. For small-signal stability discusses a methodology to identify crucial transmission lines for stability prediction by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict system stability in real-time. Also, a procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system, and it shows capabilities of the proposed method.

• KIEE International Transactions on Power Engineering
• /
• v.3A no.3
• /
• pp.161-167
• /
• 2003

This paper presents a study performed to investigate the steady-state operational strategies of UPFCs in the Jeollanam-Do system in Korea. The objective of the study was to determine the UPFC operating points under normal and contingency conditions. The study consists of developing load flow models to simulate different load levels with and without UPFCs in the system, assessing the effectiveness of UPFCs by contingency analysis, and introducing optimal corrective actions for removing voltage problems caused by contingencies. The paper describes analytical tools, models and approach. It also includes analysis and discussion of the study results. The paper contributes to the area of transmission operational studies with FACTS applications.

• Communications for Statistical Applications and Methods
• /
• v.21 no.1
• /
• pp.23-43
• /
• 2014

We study the dependence between the insureds in multiple-life insurance contracts. With the future lifetimes of the insureds modeled as correlated random variables, both premium and reserve are different from those under independence. In this paper, Gaussian copula is used to impose the dependence between the insureds with Gompertz marginals. We analyze the change of the reserves of standard multiple-life insurance contracts at various dependence levels. We find that the reserves based on the assumption of dependent lifetimes are quite different for some contracts from those under independence as its correlation increase, which elucidate the importance of the dependence model in multiple-life contingencies in both theory and practice.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.5
• /
• pp.271-278
• /
• 2003

Power system stability is correlated with system structure, disturbances and operating conditions, and power flows on transmission lines are closely related with those conditions. This paper proposes a methodology to identify correlative power flows for power system transient and small-signal stability prediction. In transient stability sense, the Critical Clearing Time is used to select some dominant contingencies, and Transient Stability Prediction index is proposed for the quantitative comparison. For small-signal stability, this paper discusses a methodology to identify crucial transmission lines for stability Prediction by introducing a sensitivity factor based on eigenvalue sensitivity technique. On-line monitoring of the selected lines enables to predict system stability in real-time. Also, a Procedure to make a priority list of monitored transmission lines is proposed. The procedure is applied to a test system and the KEPCO systems in the year of 2003 and it shows capabilities of the proposed method

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.12
• /
• pp.2131-2134
• /
• 2010

In this paper, the on-line system schemes for coordinated control system of multiple FACTS were presented to enhance the voltage stability around the metropolitan areas. In order to coordinated control system of FACTS devices, MFC on-line system calculates the optimal set point(Vref, Qrev) of FACTS devices using the coordinated control algorithm with real time network data which is transferred from SCADA/EMS system. If the system is unstable after contingencies, the new operation set-point of FACTS would be determined using bus sensitivity from tangent vector at voltage instability point. Otherwise, we would determine the new operation set-point of FACTS for considering economical operation, like as active power loss minimization using Optimal Power Flow algorithm. As the test, MFC(Multiple FACTS Coordinated control) on-line system will be installed in Korea power system.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.412-413
• /
• 2011

This paper presents a new generation rescheduling approach for preventive control of power systems, which can optimally reallocate power generations for unstable contingencies. The transient stability constraints used in the optimal rescheduling model are described by energy margin sensitivity. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.486-487
• /
• 2011

In this paper, a configurable DC distributiong system is being proposed considering national power systems conditions and a comparative analysis of the transient response of the contingencies is performed with the conventional AC systems. DC systems are evaluated as a promising next-generation distribution system that provides reliable operation through high efficiency of energy use and converter control. This paper discusses about the required elements for the national DC distribution system and has analysed the fault characteristics of the AC and DC distribution systems using PSCAD/EMTDC. According to the simulation results, the DC system has improved response, due to the DC/DC converter's charging/discharging characteristics, in terms of voltage and power system characteristics when compared to AC systems.