• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.141-144
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• 2002

Recently, the operation of power distribution systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome these problems, a study on the planning and operation in distribution systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems has been performed energetically. This study presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell systems, in the case of both only electric power supply and thermal supply as well as electric power supply. In other words, the optimal operation of these sources can be determined easily by the principle of equal incremental fuel cost and the thermal merits is evaluated quantitatively through Kuhn-Tucker's optimal conditions. In order to select the optimal locations of those sources, an priority method using the comparison of total cost at the peak load time interval is also presented. The validity of the proposed algorithms is demonstrated using a model system.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.467-475
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• 2009

Congestion management is one of the technical challenges in power system deregulation. This paper presents single objective and multi-objective optimization approaches for optimal choice, location and size of Static Var Compensators (SVC) and Thyristor Controlled Series Capacitors (TCSC) in deregulated power system to improve branch loading (minimize congestion), improve voltage stability and reduce line losses. Though FACTS controllers offer many advantages, their installation cost is very high. Hence Independent System Operator (ISO) has to locate them optimally to satisfy a desired objective. This paper presents optimal location of FACTS controllers considering branch loading (BL), voltage stability (VS) and loss minimization (LM) as objectives at once using GA. It is observed that the locations that are most favorable with respect to one objective are not suitable locations with respect to other two objectives. Later these competing objectives are optimized simultaneously considering two and three objectives at a time using multi-objective Strength Pareto Evolutionary Algorithms (SPEA). The developed algorithms are tested on IEEE 30 bus system. Various cases like i) uniform line loading ii) line outage iii) bilateral and multilateral transactions between source and sink nodes have been considered to create congestion in the system. The developed algorithms show effective locations for all the cases considered for both single and multiobjective optimization studies.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.139-142
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• 2009

The worldwide energy market is enlarging rapidly according to current issues like globalization, deregulation, global warming and strengthening for environmental regulation as well as the energy technology is developing speedily by the add of information and communication techniques. In spite of these advanced techniques in the field of the renewable energy, solar power depends on the governmental aid largely in comparison with other renewable energy sources because of the high initial investment cost. Therefore it is important to investigate scrupulously for the expected erection site of solar power plant from the planning stage. This paper shows actual measurement data of solar radiation of scheduled solar power locations in the waterworks site with consideration of waterworks facilities and regional specialties and presents the data which was analyzed comparably with the radiation data of adjacent locations served by national authorities. In addition, these data were analyzed using RETScreen and used for making decision on the business validity.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.18-34
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• 2017

The recent air transportation market is rapidly changing in air and airport infrastructure such as efficiency of airports and airplanes, speeding up and enlargement, deregulation of airline industry, low cost airlines and regional airports. The purpose of this study is to conduct a direct questionnaire survey for airport users who have experienced in and out of airport IT service at Incheon International Airport, so that the airport self - service technology and airport support technology can be used for the trust. At this point, I would like to develop a tool to understand the airport user's perception of airport IT and to test the theoretical model that investigates the relationship between various types of airport IT, airport users' trust, enjoyment and intention to use IT. In conclusion, this study aims to establish directions and suggestions for how to develop IT services among airport service provision factors.

• Korean System Dynamics Review
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• v.16 no.4
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• pp.129-153
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• 2015

Mandatory shutdown policy of the juvenile protection act was enforced in December 2011 to prevent game addiction of the youth. However, the size of game market in Korea seems to be reduced significantly after implementation of the shutdown policy. The purpose of this study is to investigate the impact of current government regulations on Korean online game market. Based on empirical evidences and results from the related literature, we developed several causal loop diagrams(CLD) and system dynamics models. The CLD include sub-diagrams of innovation processes, user commitments, and operational costs. We conducted simulation analyses under various policy scenarios, adopting Normalized Unit Modelling By Elementary Relationship(NUMBER). Our results show that first, the impact of time regulation on the number of users is greater than the impact of content regulation. Second, the quality of domestic online game appears more elastic to regulations than the quality of foreign online game. The results of this study suggest that the deregulation in Korean online game market can narrow the gap in market outcomes between domestic and foreign online games. Some recommendations for future study are suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.513-521
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• 2012

With the advent of smart grid, distribution network charges have been one of keystones of ongoing deregulation and privatization in power industries. This paper proposes a new charging methodology to allocate the existing distribution network cost with an aim of reflecting the true cost and benefit of network customers, especially of distribution generator (DG). The proposed charging methodology separates distribution network costs due to the respective real and reactive power flows. The costs are then allocated to network users according to each charge for the actual line capacity used and available capacity. This distribution network charging model is able to provide the economic signals to reward network users who are contributing to better power factors, while penalizing customers who worsen power factors. The proposed method is shown on IEEE 37 bus system for distribution network, and then the results are validated through the comparison with the MW-Miles and MVA-Miles methods. The charges derived from the proposed method can provide appropriate incentives/penalties to network customers to behave in a manner leading to a better network condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1699-1708
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• 2007

The optimal power flow(OPF) problem was introduced by Carpentier in 1962 as a network constrained economic dispatch problem. Since then, the OPF problem has been intensively studied and widely used in power system operation and planning. In these days, OPF is becoming more and more important in the deregulation environment of power pool and there is an urgent need of faster solution technique for on-line application. To solve OPF problem, many heuristic optimization methods have been developed, such as Genetic Algorithm(GA), Evolutionary Programming(EP), Evolution Strategies(ES), and Particle Swarm Optimization(PSO). Especially, PSO algorithm is a newly proposed population based heuristic optimization algorithm which was inspired by the social behaviors of animals. However, population based heuristic optimization methods require higher computing time to find optimal point. This shortcoming is overcome by a straightforward parallel processing of PSO algorithm. The developed parallel PSO algorithm is implemented on a PC cluster system with 6 Intel Pentium IV 2GHz processors. The proposed approach has been tested on the IEEE 30-bus system. The results showed that computing time of parallelized PSO algorithm can be reduced by parallel processing without losing the quality of solution.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.48
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• pp.57-76
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• 2010

This study reviews maritime transport policy regarding liner conference and the changes in the liner market over the decades. Liner shipping industry has long been protected from competition by block exemption. To prevent excessive competition in punctual operation and its inelastic market structure, liner shipping companies formed conferences that are protected to fix the prices under the law. In the US, deregulation in transport sector began from 80's and continuing with OSRA 1998, conferences were dissolving. On the other hand, the EU with close conference system, Regulation 4056/86 contained block exemption remained in force for unlimited time without review clause. However, in Oct 2008, the EU has announced its removal, and conferences were no longer permitted to fix the price nor exchange information. Although OSRA 1998 has already broken up conferences by allowing individual service contracts, but the repeal of the immunity for price fixing will alter significantly the rule on cooperation in the industry since it is a unilateral move by the EU, especially in transatlantic lane. There are rapid changes in shipping market getting much more complicated, and with removal of 4056/86 allowing the market to be more competitive, opening up the industry with far more diverse strategic options. Hence this paper reviews on liner shipping industry and its changes of policies over the years from protected market to open competition market of today.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2575-2580
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• 2015

Cancer is a multifaceted and genomically complex disease and rapidly accumulating high impact research is deepening our understanding related to the mechanisms underlying cancer development, progression and resistance to therapeutics. Increasingly it is being realized that genetic/epigenetic mutations, inactivation of tumor suppressor genes, overexpression of oncogenes, deregulation of intracellular signaling cascades and loss of apoptosis are some of the extensively studied aspects. Confluence of information suggested that rapidly developing resistance to therapeutics is adding another layer of complexity and overwhelmingly increasing preclinical studies are identifying different natural agents with efficacy and minimal off-target effects. We partition this multi-component review into citrus fruits and their bioactive ingredients mediating rebalancing of pro- and anti-apoptotic proteins to induce apoptosis in resistant cancer cells. We also discuss how oncogenic protein networks are targeted in cancer cells and how these findings may be verified in preclinical studies.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2833-2836
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• 2012

Aim: Gastric cancer is the third most frequent cause of cancer mortality worldwide. In Iran, it is one of the leading causes at the national level. Localized at chromosome 8q22, the human MTDH gene has been reported to be over-expressed in a spectrum of malignancies. However, since there is a lack of data concerning with expression in gastric cancer at the transcriptional level, in this study we evaluated MTDH expression in Iranian cases. Methods: Totally, thirty paired gastric samples were examined by quantitative real-time RT-PCR. Results: Although the mRNA expression was significantly elevated in 46.6% of the examined tumor tissues; its expression was low in others (36.6%). Moreover, there was only a marginal statistical difference between the MTDH gene expression of all tumor specimens compared to their paired non-tumor ones and no statistically significant association with the grades and types of the tumors. Conclusion: Taken together, our results demonstrated that expression of MTDH at the transcriptional level may be increased in gastric cancer tissue samples but with considerable heterogeneity. Due to this, it may have the potential to be used as a target for diagnostic/therapeutic purposes only in a subset of patients.