• Proceedings of the KIPE Conference
• /
• 2016.07a
• /
• pp.95-96
• /
• 2016

This paper presents a voltage and frequency droop control for accurate power sharing of parallel distributed generation (DG) inverters in low voltage microgrid. In practice, line impedances between inverters and the point of common coupling of a microgrid are not always equal. This inequality in line impedances often results in reactive power sharing mismatch among inverters. To address this problem, intensive researches have been conducting. Although these methods can solve the unbalanced reactive power sharing, there are still problems remain unresolved, such as complicated structure or circulating current. To overcome such problems, a new droop control scheme is proposed, which not only guarantees accurate reactive power sharing but also has simple structure so that it can be easily implemented in existing systems without any hardware modification. The simulation is performed using Matlab/Simulinks to validate the proposed scheme.

• The Journal of Society for e-Business Studies
• /
• v.3 no.2
• /
• pp.113-124
• /
• 1998

The architectural design requires collaboration among various participants, such as architects, clients and engineers in the stages of the design process. Rapid development of information technology enables effective and prompt exchange and sharing of digital architectural information, otherwise should have been exchanged and managed by traditional ways. However, the core technology for supporting this demands has not been fully investigated so far. This paper aims to show the possibility of adopting network based architectural design information sharing system through surveying and analyzing the state-of-the-art network technology and its uses in architectural information exchange among various design actors. To realize these aims, this paper 1) investigates and analyzes the current status of network technology in the architectural and construction practice, 2) suggests systematic information exchange and sharing mechanism for architectural products and drawings data, and 3) demonstrates network based prototypical architectural information system.

• Electronics and Telecommunications Trends
• /
• v.36 no.5
• /
• pp.51-61
• /
• 2021

To reduce mobile network deployment costs and expand service coverage, mobile infrastructure sharing is becoming increasingly important. This paper introduces the concept and potential benefits of mobile infrastructure sharing as documented in the existing literature. Then, the current status of significant cases of mobile infrastructure sharing in major overseas countries is examined. Finally, sharing 5G infrastructure in rural areas in Korea is introduced. The Korean case is expected to complete national 5G coverage successfully without involving negative competition.

• The KIPS Transactions:PartC
• /
• v.11C no.6 s.95
• /
• pp.739-746
• /
• 2004

License mechanisms are the key elements in almost all DRM(digital rights management) systems. The license mechanisms are designed for the clear identification and enforcement of contents, principals, and usage rules in DRM systems. But current license mechanisms are lacking in the flexibility for the secure and efficient sharing of the contents among the members of a group such as a family or a part of an enterprise. This paper suggests a new license mechanism for efficient and secure sharing of contents in DRM systems among the members of a group. We named it member/group license mechanism. The mechanism extends the current license mechanisms by introducing new concepts such as group licenses, member licenses, and derivation relationships between licenses.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.4
• /
• pp.341-349
• /
• 2004

A parallel operation of Uninterruptible Power Supply(UPS) systems is used to increase power capacity of the system or to secure higher reliability at critical loads. In the conventional parallel operation, the load-sharing control to maintain the current balance is the most important, since the load-sharing is very sensitive to discord between components of each module, amplitude/phase difference, line impedance, output LC filter, and so on. To solve these problems various control algorithms are researching. However, these methods cannot apply to the different ratings of UPS. In the case, master and slave control algorithm for parallel operation is adequate. However, if the UPS ratings are different, the value of passive filters L, C is different, and it affects the sharing of current. This paper presents general problems of conventional parallel operation systems, and control strategy for parallel operation with different ratings. The validity of the proposed control strategy is investigated through simulation and experiment in the parallel operation system with two 3-phase UPS systems.

• Journal of the Semiconductor & Display Technology
• /
• v.22 no.4
• /
• pp.161-165
• /
• 2023

This paper designed a voltage feedback driving circuit to compensate for the characteristic deviation of the Active Matrix Organic Light Emitting Diode driving Thin Film Transistor. This paper describes a stable and fast circuit by applying charge sharing and polar stabilization methods. A 12-inch Organic Light Emitting Diode with a Double Wide Ultra eXtended Graphics Array resolution creates a screen distortion problem for line parasitism, and charge sharing and polar stabilization structures were applied to solve the problem. By applying Charge Sharing, all data lines are shorted at the same time and quickly positioned as the average voltage to advance the compensated change time of the gate voltage in the next operation period. A buffer circuit and a current pass circuit were added to lower the Amplifier resistance connected to the line as a polar stabilization method. The advantage of suppressing the Ringing of the driving Thin Film Transistor can be obtained by increasing the stability. As a result, a circuit was designed to supply a stable current to the Organic Light Emitting Diode even if the characteristic deviation of the driving Thin Film Transistor occurs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.10
• /
• pp.1005-1019
• /
• 2014

In this paper, we proposed the frequency candidates band for the spectrum sharing through researching and analyzing the current status of the policy and the economic values which is actively conducted on the United States and Europe. To this end, we investigated to the status and problems with the frequency reallocation and arrangement in respond to the current frequency demand. To solve these frequency reallocation and arrangement method problems, we introduce to the concept and current status of policy for the frequency method progress by advanced countries mainly. Also the results of the economic value analysis introduced in terms of the operators. In addition, we proposed the assessment terms and criteria for the selection of frequency candidates band through joint research and analysis results.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.3
• /
• pp.188-194
• /
• 2020

This paper presents a high-efficiency Switch Mode Line Transformer (SMLT) composed of load-shared dual modules, which is based on the AC/AC LLC resonant converter. Given that the conventional adaptor is usually composed of two power stages, namely, the PFC and DC/DC converters, its system size can be increased according to the output power. However, given that the proposed SMLT can separate the PFC converter from the adaptor, the size reduction of the system can be achieved. Meanwhile, the SMLT with a single module has the limit of the size reduction because of a high resonant current. Thus, it can be configured with dual or multiple modules to reduce the resonant current. Then, their load sharing can be guaranteed by only the proposed transformer structure without an extra current controller. The validity of the proposed converter is proven through a 850-W prototype.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.8
• /
• pp.3603-3609
• /
• 2011

In this paper, we proposes new load-sharing algorism for equal current division using CAN communication. Proposed algorithm is different from conventional analog method, it performed strong Load-sharing using bi-direction high speed communication. Each modules constitution on independence controller (voltage controller, electric current controller). In parallel system prototype, each module have controller and performed load-sharing according to master module integral value. Also additional controller use for getting each module situations that fault situation of module and fault locate of module. we implemented high efficient load-sharing and redundancy. In this paper, we verify the validity of proposed algorithm using PSIM program and prototype.

• Journal of the Korean Society of Food Culture
• /
• v.20 no.6
• /
• pp.683-687
• /
• 2005

This study examined food sharing characteristics revealed in the modern Korean society by both interpreting phenomena and analyzing literature. Diet was said to be the least influenced by western modernization in Korea. Concerning this matter, one of the important explanations to be considered would be a strong influence of 'the first settlement effect' in culture, as reviewed elsewhere. Sharing food means not only sharing food itself but also sharing communal solidarity. The latter was strongly emphasized in Korean food culture due to his own historical grounding. Some examples revealed in current Korea included sometimes too much generous treat when eating out, even saliva allowed food sharing, too much food provision, and too many restaurants. 'Dutch treat' observed in many occasions of food sharing in Korea was also viewed as a product of historical experience, which was related to the degree of traits of feudalism in modern societies as feudalism was based on a sort of a give and take contract. The association of the degree of traits of feudalism and communal solidarity was explored by comparing so called different meal treat manners between Koreans and Japanese, that is, more generous attitude among the former. The concept of communal solidarity was also examined with respect to Koreans' side dish sharing behaviors which sometimes accompanied seemingly insanitary saliva sharing. In addition, provision of too much food was analyzed by relating this manner to a traditional 'hand over dining table' custom. Traditionally, food on a dining table was not supposed to be only for those sitting on the table. Even though the 'hand over dining table' was no longer well preserved at present time, its cultural traits appeared to be well prevailed in the modern Korean society. Finally, an increase of restaurants as well as an increase of eating out occasions were postulated with respect to the notion that restaurants were the places for ascertaining communal solidarity while sharing foods. The above analyses suggest the importance of the influence of sharing originated from his/her own historical grounding for better understanding of modern Korean food culture.