• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.299-305
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• 2013

The complexity and severe nonlinearity of multi-machine power systems make it difficult to design a control input for voltage regulation using modern control theory. This paper presents a model-based PID control scheme for the regulation of the bus voltage to a desired value. To this end, a fourth-order linear system is constructed using input and output data obtained using the TSAT (Transient Security Assessment Tool); the input is assumed to be applied to the grid through the STATCOM (STATic synchronous COMpensator) and the output from the grid is a bus voltage. On the basis of the model, it is identified as to which open-loop poles of the system make the response to a step input oscillatory. To reduce this oscillatory response effectively, a model-based PID control is designed in such a way that the oscillatory poles are no longer problematic in the closed loop. Simulation results show that the proposed PID control dampens the response effectively.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.55-57
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• 2007

A Power control and Distribution Unit (PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU for the small Low Earth Orbit (LEO) Satellite applications. The main constitutes of the PCDU are the battery interface module, solar array regulators with maximum power point tracking (MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation, power distribution modules of unregulated and regulated primary bus, and instrument power distribution modules.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.629-638
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• 2005

In the System on a Chip design, the on chip bus is one of the critical factors that decides the overall system performance. Especially, in the case or reusing the IPs such as processors, DSPs and multimedia IPs that requires higher bandwidth, the bandwidth problems of on chip bus are getting more serious. Recently ARM proposes the Multi-Layer AHB BusMatrix that is a highly efficient on chip bus to solve the bandwidth problems. The Multi-Layer AHB BusMatrix allows parallel access paths between multiple masters and slaves in a system. This is achieved by using a more complex interconnection matrix and gives the benefit of increased overall bus bandwidth, and a more flexible system architecture. However, there is one clock cycle delay for each master in existing Multi-Layer AHB BusMatrix whenever the master starts new transactions or changes the slave layers because of the Input Stage and arbitration logic realized with Moore type. In this paper, we improved the existing Multi-Layer AHB BusMatrix architecture to solve the one clock cycle delay problems and to reduce the area overhead of the Input Stage. With the elimination of the Input Stage and some restrictions on the arbitration scheme, we tan take away the one clock cycle delay and reduce the area overhead. Experimental results show that the end time of total bus transaction and the average latency time of improved Multi-Layer AHB BusMatrix are improved by $20\%\;and\;24\%$ respectively. in ease of executing a number of transactions by 4-beat incrementing burst type. Besides the total area and the clock period are reduced by $22\%\;and\;29\%$ respectively, compared with existing Multi-layer AHB BusMatrix.

• Journal of the Korea Society of Computer and Information
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• v.26 no.6
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• pp.81-88
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• 2021

In this paper, we design and implement a bus information notification application based on the GPS sensor of a smartphone. This application provides the ability to check bus stops within a radius of 200m based on the current user's location using the smartphone's GPS sensor, Google Map, and open API. In addition, if you click the marker of the desired stop, you can see the name of the stop, and click the view arrival information button to check the detailed bus arrival information of the stop. In addition, it provides a function to check the location information of pharmacies, nonghyups, and post offices that sell public masks, the names of public mask stores, and mask inventory through the public mask store button. Each icon was used differently to make visual differences in order to easily indicate the difference between the times of public mask sales and bus stops. In addition, if you want to know the information of other bus stops and the route of the desired bus, not around the user's location, click the bus stop search button. Finally, after storing the destination stop or location, it implements a function that provides an alarm when it approaches the location.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.425-430
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• 2016

This study is to improve the design of bus transfer information that can be substantially used. This study has been processed using the following steps. First, I tried to define the information design and way-finding information design. Secondly, I have researched several case studies, and considered solutions. Finally, I evaluated way-finding maps through pair-wise comparisons, and drew needs through an interview. As the result of this research, there were some problems in font size, improper space between letters and non-consistent information. To solve these problems, the information has to be clear using easy symbols to be well-recognized by citizens. Also, the font size needs to be decided by a calculation of minimum legible size of letters. Lastly, a value contrast between a background color and a letter color needs to be applied more than 70 percent for better visibility. The study is expected to be used as a reference which helps informational design to be developed.

• Design Convergence Study
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• v.13 no.5
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• pp.131-145
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• 2014

Considering the number of population commuting from Gyeonggi to Seoul, the development of the bus system is relatively slow. There are many problems to be solved but it has been overlooked, leaving the users in discomfort. The goal of this research is to improve the current system to satisfy the unmet needs, using HCI methods, which is composed of five steps, including Define, Find, Analyze & Synthesize, Ideation, Develop. In Define, we recruited the interviewees using the extreme user method to find their needs. In Find, we proceeded 'be the customer', shadowing for background research and in-depth interview. In Analyze & Synthesis, we analyzed the customer needs and clustered to similar needs to draw useful ideas. After that we suggested sophisticated ideas based on design principles from previous stage and visualized in user scenarios and mock-ups. Overall, the research suggests with text message service, informative light service and mobile application to improve the existing bus station.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2348-2356
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• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2515-2517
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• 1999

In this paper we analysis DC bus voltage stress at high line voltage and light load in $S^4$-PFC Isolated AC/DC converter with DC bus voltage feedback using coupling in transformer. In this converter, the principle of operation and the practical problems in the design are considered. Simulation and experimental results are presented to verify the operation and performance of the $S^4$-PFC converter with DC bus voltage feedback. Experimental sets are performed in the conditions; switching frequency 100 kHz, output of 5 V, 60W, and universal line input voltage.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.569-570
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• 2008

This paper proposed a new arbitration method in arbiter which is one of bus system components for the design of SoC. Considering compatibility between IP and bus system, the performance of bus system can change the performance of SoC chip. The proposed arbitration method achieved the performance improvement with high efficiency depending on the environment in use.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.1013-1013
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• 2004

Soundscape design is applied for the purpose of expressing the characteristics of places, by supplying suitable background sound for various places expressing their identity. Bus stations are a place for aggregating people using transportation. That is, people go into a station, buy a ticket, and wait for departure or for other passengers. Therefore, they need to create a more comfortable sound environment. This study aims to make bus stations a comfortable place acoustically for users. In this study, analysis on behavior at various locations in the space was performed. Measurements were taken on the approaching path, waiting place, departure and arrival platforms for sound levels and frequency characteristics. In addition, on acoustic specialists evaluation, using questionnaires, was also performed ambient noise, information broadcasting and users dialogue.