• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.141-144
• /
• 2006

The deviations in the injection orbital parameters, resulting from launcher dispersions, need to be estimated and used for autonomous satellite operations. For the proposed small satellite mission of the university there will be two GPS receivers onboard the satellite to provide the instantaneous orbital state to the onboard data handling system. In order to meet the power requirements, the satellite will be sun-tracking whenever there is no imaging operation. For imaging activities, the satellite will be maneuvered to nadir-pointing mode. Due to such different modes of orientation the geometry for the GPS receivers will not be favorable at all times and there will be instances of poor geometry resulting in no output from the GPS receivers. Onboard the satellite, the orbital information should be continuously available for autonomous switching on/off of various subsystems. The paper presents the strategies to make use of small arcs of data from GPS receivers to compute the mean orbital parameters and use the updated orbital parameters to calculate the position and velocity whenever the same is not available from GPS receiver. Thus the navigation message from the GPS receiver, namely the position vector in Earth-Centered-Earth-Fixed (ECEF) frame, is used as measurements. As for estimation, two techniques - (1) batch least squares method, and (2) Kalman Filter method are used for orbit estimation (in real time). The performance of the onboard orbit estimation has been assessed based on hardware based multi-channel GPS Signal simulator. The results indicate good converge even with short arcs of data as the GPS navigation data are generally very accurate and the data rate is also fast (typically 1Hz).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.5
• /
• pp.667-679
• /
• 2015

The bearer of the power sector's ETS compliance cost is power consumer for the following reasons. Firstly, power companies are constrained in establishing appropriate strategies to comply with ETS regulations due to the structural differences between the domestic power market and emission trading system. In other words, because power companies do not have a right to determine price and production of electricity, they have to compete with other companies under disadvantaged conditions in the emission trading market. Secondly, because ETS compliance cost is part of power production costs as it is also clearly written in the national greenhouse gas reduction road-map and the second energy supply plan, the cost should be included in power price following the power market operation rule. Thirdly, the most effective method to reduce carbon emissions in power sector is to reduce power demand, which is efficiently achieved through raising power price to a realistic level. Low power price in Korea is the major cause of rising power demand which is also the major cause of rising GHG emission. Therefore, power sector's ETS compliance cost should be included in power price to encourage power consumers' actions on reducing power consumption. Fourthly, when externality cost occurs in the process of delivering public services, usually beneficiary pay principle is applied to identify the cost bearer. Since electricity is one representative public good, the bearer of power sector's ETS compliance cost is power consumer.

• Korean Institute of Interior Design Journal
• /
• no.9
• /
• pp.77-85
• /
• 1996

The purpose of this study is to examine losely how the Rococo style, which reached its summit in the history of French furniture, was realized in its social background and mode of life. Based ion this examination , this study will explore desirable directions for developing our domestic furniture design. For this purpose , existing literature will be referred to and analyzed to arrange into a new system. Rococo furniture style was the product of joyous and aristocratic living . This was based upon the historical development of French interior design, established by the national mode of Versailles Palace. Hereafter, royal style came into fashion paralleled with the luxuries of the court. Pursuit of new , interesting or beyond-expectation fashions encouraged the creation of new and imaginative forms and designs . The elegnant taste of customers, the new techniques of furniture manufacturing , and the unique sales strategies of merchants were social phenomena which contributed to the development of Rococo furniture. Furthermore , Louis XV`s private and personal life led to society`s pursut of comfortable and convenient living . Under these circumstances, small and cozy rooms for various uses came into the interior. Accordingly, the scales of furniture became smaller and any types of furniture with their own uses and feminine nature were manufactured , especially by the bnistes. Rococo furniture with fmine beanty and refined line, beatifil proportion and elegant sculpture, and solidity and clarity in general , is not only furniture for the use of man, but also furniture in harmony with man. As we see the stages of development and the characteristics of Rococo furniture, development of Korean furniture is a common task which can be accomplished through the participation of the designer, manufacturer, seller and consumer. Based on this co-operation , the furniture industry must make an improvement in furmture design, lestablish a permanent store in which new works are displayed. publicize activities and sales, promote exhibitions and seminars, and encourage technical development through the government and other interested organizations.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.127-129
• /
• 2007

Since the competitive market environment was introduced into the electric power industry, the structure of the industry has been changing from vertically integrated system to functionally unbundled and decentralized system composed of multiple (decision-making) market participants. So the market participants such as Gencos or LSE (load serving entity) need to forecast the market clearing price and thus build their offer or bidding strategies. Not just these market players but also a market operator is required to perform market analysis and ensure simulation capability to manage and monitor the competitive electricity market. For fulfilling the demand for market simulation, many global venders like GE, Henwood, Drayton Analytics, CRA, etc. have developed and provided electricity market simulators. Most of these simulators are based on the optimization formulation which has been used mainly for the least cost resource planning in the centralized power system planning and operation. From this standpoint, it seems somehow inevitable to face many challenges on modeling competitive market based on the method of traditional market simulators. In this paper, we propose a kind of new method, which is MAS based market simulation. The agent based model has already been introduced in EMCAS, one of commercial market simulators, but there may be various ways of modeling agent. This paper, in particular, seeks to introduce an model for MAS based market simulator.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.5
• /
• pp.3525-3534
• /
• 2015

One of the most important requirements in the development of asset management system of wastewater facilities is to determine the level of management of the service related to supply of wastewater. After the sewage facilities were built, many parts of the replacement or repair items will be occurred by the requests of the users on the way of operation and management. To manage the level of those services, where site and which complains is occurred have to be searched, and have to setting the aim of managing the service for objects to improvement. In this study, the complaints related with the sewage of S-area were analyzed, in which is progressed the domestic asset management development for the facilities and pipes related to wastewater. Based on these complaints data, the regional characteristics of S-area by causes and subject of complaints is analysed, and developed more detail management standard than current level. And also service level management strategies of advanced asset management benchmark agency for improving to service level management standard is compared and constructed basement for building the best practice of S area.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.2078-2087
• /
• 2009

The Air and Correspondence High School (ACHS) has played a key role as an organization of lifelong learning since 1974. However, extra-curriculum in ACHS has not been operated successfully due to lacks of educational supports and on-line contents. So we surveyed demands of the ACHS teachers and students for successful operation of extra-curriculum, found four subjects that students preferred in the developing activity area which is one of extra-curricular activities, and experimentally developed four on-line contents for extra-curriculum. And we also applied the developed on-line contents to the students of Chongju H.S. After the application, another survey and interview were carried out to measure learner's satisfaction, find out problems of learning with on-line contents and suggest the ways of improving extra-curriculum learning system.

• Journal of KIISE:Information Networking
• /
• v.36 no.3
• /
• pp.163-172
• /
• 2009

Various terminals equipped with multiple interfaces may receive services from wireless networks when they pass through the overlaid heterogeneous networks, and thus the vertical handovers across the wireless networks increases, which will become a big problem in the network resource management. This problem can be efficiently solved by common radio resource management (CRRM). In this paper, we propose two operation algorithms based on network selection jointly with vertical handover as the key CRRM strategies. When a new user tries to get services, the CRRM can choose the best target network according to the proposed Integrated Network Selection Algorithm. When the network cannot satisfy the request from the new users, the proposed Integrated Vertical Handover Algorithm moves existing users to neighborhood networks to accommodate new users. The performance of the proposed algorithms has been validated through extensive simulations.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.8
• /
• pp.401-410
• /
• 2017

This paper proposes a method to generate test cases in an automatic manner, based on checklist containing test cases used for testing embedded systems. In general, the items to be tested are defined in a checklist. However, most test case generation strategies recommend to test a system with not only the defined test items but also various mutated test conditions. The proposed method parses checklist in Korean file and figures out the system inputs and outputs, and operation information. With the found information and the user defined test case generation strategy, the test cases are automatically generated. With the proposed method, the errors introduced during manual test case generation may be reduced and various test cases not defined in checklist can be generated. The proposed method is implemented and the experiment is performed with the checklist for an medical embedded system. The feasibility of the proposed method is shown through the test cases generated from the checklist. The test cases are adequate to the coverages and their statistics are correct.

• Journal of Information Processing Systems
• /
• v.14 no.1
• /
• pp.162-175
• /
• 2018

Currently, electricity consumption and feedback mechanisms are being widely researched in Internet of Things (IoT) areas to realise power consumption monitoring and management through the remote control of appliances. This paper aims to develop a smart electricity utilisation IoT platform with a deep belief network for electricity utilisation feature modelling. In the end node of electricity utilisation, a smart monitoring and control module is developed for automatically operating air conditioners with a gateway, which connects and controls the appliances through an embedded ZigBee solution. To collect electricity consumption data, a programmable smart IoT gateway is developed to connect an IoT cloud server of smart electricity utilisation via the Internet and report the operational parameters and working states. The cloud platform manages the behaviour planning functions of the energy-saving strategies based on the power consumption features analysed by a deep belief network algorithm, which enables the automatic classification of the electricity utilisation situation. Besides increasing the user's comfort and improving the user's experience, the established feature models provide reliable information and effective control suggestions for power reduction by refining the air conditioner operation habits of each house. In addition, several data visualisation technologies are utilised to present the power consumption datasets intuitively.

• Journal of Power Electronics
• /
• v.18 no.1
• /
• pp.212-224
• /
• 2018

For maintaining a reliable and secure power system, this paper describes the design and implement of a single-phase grid-connected inverter with an enhanced phase-locked loop (PLL) and excellent power control performance. For designing the enhanced PLL and power regulator, a full-bridge voltage-controlled inverter (VCI) is investigated. When the grid frequency deviates from its reference values, the output frequency of the VCI is unstable with an oscillation of 2 doubling harmonics. The reason for this oscillation is analyzed mathematically. This oscillation leads to an injection of harmonics into the grid and even causes an output active power oscillation of the VCI. For eliminating the oscillation caused by a PLL, an oscillation compensation method is proposed. With the proposed method, the VCI maintains the original PLL control characteristics and improves the PLL robustness under grid frequency deviations. On the basis of the above analysis, a power regulator with the primary frequency and voltage modulation characteristics is analyzed and designed. Meanwhile, a small-signal model of the power loops is established to determine the control parameters. The VCI can accurately output target power and has primary frequency and voltage modulation characteristics that can provide active and reactive power compensation to the grid. Finally, simulation and experimental results are given to verify the idea.