• Journal of Power System Engineering
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• v.14 no.1
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• pp.40-46
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• 2010

This paper shows the development process for measuring three-dimensional flow velocity components in a web-browser. The system is developed in an embeddable C/C++ interpreter Ch and Ch-CGI toolkit. The interface for the web-based measurement system consists of a set of web HTML files and Ch files for CGI. All of data in web browser are passed to Ch-CGI script to generate the output of new HTML file. PC-Server and PC-Client can submit measurement parameters and receive the text/graphical results each other. PC-Client can control the test equipment by using a parameters that received from PC-Server. It also can pass the test results between the web-based measurement system. In summary, the designed measurement system is evaluated, the outputs shown well on the web browser.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.377-384
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• 1999

In this paper, client/server model for remote conveyor control and monitoring system is designed and implemented to simulate the product line of vehicles. The client system located at the monitoring office is using a web applet based system, and sends some commands to the server system which guards and controls the conveyer system directly. And server system is implemented as the web based system by using Java programming language too. The system has a distributed database system environments to manage and maintain the product line of conveyor system.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.63-66
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• 2022

The article discusses the application of the IoT concept in the sensitive field of medical devices on the example of a developed prototype of a mechanotherapeutic simulator. Mechanotherapy is a complex of therapeutic, preventive, and restorative exercises conducted using simulators, specially designed for developing movements in individual joints. Mechanotherapy is used for the early and painless restoration of joint mobility, to prevent complications associated with prolonged immobilization of the injured area of extremities. Using the mechanotherapy simulator allows developing the joint painlessly, which accelerates the metabolism in the injured area, and soft tissues are restored to normal. The article provides information about the electronic components that ensure the wireless operation of the device and describes in detail the applied software as well as the client application for a mobile device.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.128-135
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• 2003

A fairness control method for Distributed-Queue Dual-Bus(DQDB) has been studied under specific traffic types such as equal probability traffic, symmetric traffic and asymmetric traffic. To distribute DQDB network bandwidth fairly to all stations under general traffic such as a client-server traffic that differs from specific traffic types, we propose an effective fairness control method. Based on an access limit, the proposed mechanism applies two bandwidth control mechanisms to DQDB networks. One is the mechanism that is called APS(Access Protection Scheme) for servers. And another is the mechanism that controls the allocation of bandwidth only using an access limit lot clients. Simulation results show that it outperforms other mechanisms.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1212-1220
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• 2010

The technologies of domestic user programs are not enough to convert address convert information, which was collected via port redirection server, to user traffic. Generally traffic redirection technology is a special purpose technology for I/O traffic via network device. L4 switch needs various additional costs and devices to achieve this special purpose. To solve this problem, there appears need for a central management of control and monitoring by centralizing traffic at one position regardless of network structure and it is necessary to realize redirection function of switch at network layer. Therefore this study offer development of traffic central control system through protocol redirection of client-side.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2512-2531
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• 2014

We propose a new Distributed Denial of Service (DDoS) defense mechanism that protects http web servers from application-level DDoS attacks based on the two methodologies: whitelist-based admission control and busy period-based attack flow detection. The attack flow detection mechanism detects attach flows based on the symptom or stress at the server, since it is getting more difficult to identify bad flows only based on the incoming traffic patterns. The stress is measured by the time interval during which a given client makes the server busy, referred to as a client-induced server busy period (CSBP). We also need to protect the servers from a sudden surge of attack flows even before the malicious flows are identified by the attack flow detection mechanism. Thus, we use whitelist-based admission control mechanism additionally to control the load on the servers. We evaluate the performance of the proposed scheme via simulation and experiment. The simulation results show that our defense system can mitigate DDoS attacks effectively even under a large number of attack flows, on the order of thousands, and the experiment results show that our defense system deployed on a linux machine is sufficiently lightweight to handle packets arriving at a rate close to the link rate.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.250-252
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• 2006

Web technologies are gaining increased importance in automation and control systems. However, the choice of Web technologies depends on the use cases in the application environment. In industrial systems, the data can be got not only from many different field systems and devices but also from different OPC (OLE for Process Control) Servers. Current OPC Client might be able to read simple data from OPC Server, but there are some problems to get structured data and to exchange structured information between collaborating applications. Therefore, OPC Foundation has defined interfaces to OPC XML-DA (OPC XML Data Access) and OPC Complex Data that aim to solve those problems. The OPC XML-DA can facilitate the exchange of plant data across the internet, and upwards into the enterprise domain. In addition, the OPC Complex Data will extend the OPC DA specification to allow the OPC Client to read and decode any type of data from measurement and control systems on the plant floor. This paper will describe the concept of OPC XML-DA and OPC Complex Data. And then it proposes a mechanism to implement the OPC Complex Data into OPC XML-DA Server. Additionally, the paper also discusses the security aspects.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.270-274
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• 2002

This paper presents a teleoperation system that combines computer network and an autonomous mobile robot. We control remotely an autonomous mobile robot with vision over the Internet to guide it under unknown environments in the real time. The main feature of this system is that local operators need a web browser and a computer connected to the communication network and so they can command the robot in a remote location through the home page. The hardware architecture of this system consists of an autonomous mobile robot, workstation, and local computers. The software architecture of this system includes the client part for the user interface and robot control as well as the server part for communication between users and robot. The server and client systems are developed using Java language which is suitable to internet application and supports multi-platform. Furthermore. this system offers an image compression method using JPEG concept which reduces large time delay that occurs in network during image transmission.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.435-446
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• 2001

In this paper, a new fairness control method is proposed to distribute DQDB-SR (Distributed-Queue Dual-Bus with Slot Reuse) network bandwidth fairly to all stations on client-server environments. By using an access limit that follows a characteristic of client-sever load patterns and a bandwidth borrowing and returning mechanism, the proposed mechanism imparts fairness bandwidth control capability to DQDB-SR. To implement the proposed mechanism, we find the optimal placement of erasure nodes that maximizes network capacity for DQDB-SR, and calculate the access limit. At overload conditions, simulation results show that the proposed mechanism does not deteriorate network throughput, and outperforms other fairness control mechanisms in a success rate and an average packet transfer delay.

• Journal of Power Electronics
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• v.14 no.5
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• pp.1069-1078
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• 2014

This study presents the design and implementation of a web-based remote laboratory for a multi-mode single-leg power converter, which is a topic in advanced power electronics course. The proposed laboratory includes an experimental test rig with a multi-mode single-leg power converter and its driver circuits, a measurement board, a control platform, and a LabVIEW-based user interface program that is operated in the server computer. Given that the proposed web-based remote laboratory is based on client/server architecture, the experimental test rig can be controlled by a client computer with Internet connection and a standard web browser. Although the multi-mode single-leg power converter can work at four different modes (main boost, buck-boost, boost-boost, and battery boost modes), only the buck-boost mode is used in the experiment because of page limit. Users can choose the control structure, control parameters, and reference values, as well as obtain graphical results from the user interface software. Consequently, the feedbacks received from students who conducted remote laboratory studies indicate that the proposed laboratory is a useful tool for both remote and traditional education.