• Journal of Electrical Engineering and Technology
• /
• v.8 no.5
• /
• pp.1212-1220
• /
• 2013

In general, for a large power system like DC distribution system for buildings, several power converters are modularized for parallel operation. However, in parallel operation, inconsistency of parameters in each module causes circulating current in the whole system. Circulating current is directly related to loss, and, therefore, it is most important for the safety of the power system to supply the suitable current to each module. This paper proposes a control method to reduce circulating current caused during parallel operation. Accordingly, the validity of parallel operation system including response characteristics and normal state was verified by simulation and experiment result.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.5
• /
• pp.1516-1539
• /
• 2022

This article shows a set of physical information fusion IoT systems that we designed for smart buildings. Its essence is a computer system that combines physical quantities in buildings with quantitative analysis and control. In the part of the Internet of Things, its mechanism is controlled by a monitoring system based on sensor networks and computer-based algorithms. Based on the design idea of the agent, we have realized human-machine interaction (HMI) and machine-machine interaction (MMI). Among them, HMI is realized through human-machine interaction, while MMI is realized through embedded computing, sensors, controllers, and execution. Device and wireless communication network. This article mainly focuses on the function of wireless sensor networks and MMI in environmental monitoring. This function plays a fundamental role in building security, environmental control, HVAC, and other smart building control systems. The article not only discusses various network applications and their implementation based on agent design but also demonstrates our collaborative information fusion strategy. This strategy can provide a stable incentive method for the system through collaborative information fusion when the sensor system is unstable in the physical measurements, thereby preventing system jitter and unstable response caused by uncertain disturbances and environmental factors. This article also gives the results of the system test. The results show that through the CPS interaction of HMI and MMI, the intelligent building IoT system can achieve comprehensive monitoring, thereby providing support and expansion for advanced automation management.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.6
• /
• pp.1343-1355
• /
• 1997

Full motion video data is the most effective data type that transmits information in multimedia enviornment. VOD service is system that uses network to transmit full motion video data interactively. Therefore VOD service system must satisfy the following requirements. First, it should transmit high quality full motion video. Second, it should be able to control a large quantity of full motion video. Third, a user should be able to retrieve the full motion vide effectively. However the existing VOD service system is established based n file system that not only does it have disadvantages in managment such as transaction control but also it is not suitable for distributed multimedia environment. The goal of this research is to build a VOD service system that provides high-quality full motion video assuming information retrieval. In order to mainly search video data's bibliographical information and to manage related information, VOD service system and DBMS system are to be closely related. Also, to transmit high quality full motion video data, we use MTP$^{TM}$(Media Transfer Protocol) developed by StarLight. MTP$^{TM}$ guarantees high bandwidth that is necessary to tansmit high quality full motion video data effectively. In other hand TCP/IP which is used for information search does not guarentee high bandwidth as that in MTP$^{TM}$. Therfore VOD service system that seraches information managed by DBMS and transmits requried full motion video data should control different kinds of protocol simultaneously. This paper describes the configuration of VODB system that has solved these problems, implementation and efficiency of data applied system.stem.

• Proceedings of the KIEE Conference
• /
• 2004.07d
• /
• pp.2383-2385
• /
• 2004

Network uncertainties can vary the stability property of networked control system. Therefore, the performance and the stability variation of networked control system due to network uncertainties must be considered first in designing networked control system. In this paper, we present a new stability analysis method of networked control system with data loss and time delay. The proposed method can determine maximum allowable time delay and allowable transmission rate that preserves stability performance of networked control system. The results of the simulation validate effectiveness of our stability analysis methods.

• Proceedings of the IEEK Conference
• /
• 2002.06c
• /
• pp.37-40
• /
• 2002

Intelligent Wearable Module is intelligent system that arises when a human is part of the feedback loop of a computational process like a certain control system. Applied system is mobile robot. This paper represents the mobile robot control system remote controlled by Intelligent Wearable Module. So far, owing to the development of internet technologies, lots of remote control methods through internet have been proposed. To control a mobile robot through internet and guide it under unknown environment, We propose a control method activated by Intelligent Wearable Module. In a proposed system, PDA acts as a user interface to communicate with notebook as a controller of the mobile robot system using TCP/IP protocol, and the notebook controls the mobile robot system. Tlle information about the direction and velocity of the mobile robot feedbacks to the PDA and the PDA send new control method produced from the fuzzy inference engine.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1833-1837
• /
• 2004

The two-inertia system, which has the torsion vibration, is typically found in several industrial applications. This torsion vibration will effect the quality of the rolled material as well as the stability of the drive system. Thus the speed and torsion vibration of the system have to be properly controlled. This paper, I-PDA controller designed by Coefficient Diagram Method to control a two-inertia system is proposed. The experimental result shows that both of transient and steady state specification can be fulfilled but the transient response still has long rise time. In order to improve the speed of the system response, a phase lag structure of feedforward controller is introduced to I-PDA control system. It is shown that the performance of the I-PDA control system with suitable FFC has shorter rise and settling times, no overshoot and the torsion vibration can be suppressed.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.1
• /
• pp.100-111
• /
• 1999

This paper resents a discrete-time model of an edge-following with accommodation force control. Since an irregular workpiece shape causes disturbances to the system while following an edge, the use of preview control is proposed to improve the system performance. The preview control employs future information of the workpiece contour shape, and it can be developed by LQ-optimal control principles. This study provides a general method how to utilize the local future information obtained by the finite preview to minimize an optimality criterion evaluated over a problem duration. The force controller is designed based on the preview control scheme, and then implemented on a VME-based computer. Experimental results using an industrial robot show that the preview control system achieves faster tracking speed and better force regulation than the conventional nonpreview control system.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.15 no.3
• /
• pp.79-87
• /
• 2019

The system proposed in this paper is a fully automated parking control system that can even protect users' information through blockchain. Unlike conventional parking control systems, the system consists of a web page that is accessible to people of all ages and ages, directly to the parking lot. Such a system would also benefit managers in the parking lot business. This is because it can reduce soaring labor costs and maximize the sales it can generate by operating 24 hours a day. In order to implement these systems, the web page was first designed using HTML and the API was configured using JAX-RS to invoke the API required by the web page. As a result, it created a web page that was easily accessible to anyone, built a server that could be accessed by more than 200 people at the same time, focused on personal information protection by encrypting the information of users through blockchain grafts, and designed a system that enabled users to complete payments easily. It is planning to add QR codes and GPS functions in the future and implement a function that allows one-touch information on parking lots and their vehicle information.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.85-87
• /
• 2004

Supervisory control and data acquisition (SCADA) systems are essential parts of power system which employ a wide range of computers and communication technologies. The traditional SCADA system is mainly for information exchange in only one company, and the information is provided only to the operator or administrator. But in the deregulated environment, we need much more information, which can be exchanged among different companies. With the rapid development of internet, we can use it to access information easily. This paper proposes web technologies to be applied in power system in order to display some important information through accessing data from database, and to realize the real time control of the substation. The functions of SCADA system will be implemented by a set of Web-based components. The monitoring and control of standard 154[kV] substation model is already realized in the laboratory test. The Web-based SCADA system is able to provide sufficient information and control for pow or system through an efficient and economical way.

• Journal of Internet Computing and Services
• /
• v.19 no.2
• /
• pp.27-32
• /
• 2018

In industries that are operating various enterprise systems, new systems are integrated and operated in accordance with each period. In particular, when a new system is to be integrated, one of the major considerations is the single sign-on part for integrating and operating the authentication. To implement this authority system using role-based access control method, an extension method for access control method is needed. Therefore, in this paper, we design an extended role-based access control model for interworking with legacy authority system and provide its APIs. The extended role-based access control model is a model in which external authority information, which holds authority information in the authority information, is added. And we describe operations that the REST Web APIs are based on these models. In this paper, the method is described in the back-end APIs and can be implemented as an operation of an extended role-based access control system based on the method.