• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.82-86
• /
• 2001

This papers deals with feasibility study of wireless motion control. Wireless telecommunication advances with development of IT technology and extends more and more areas. So we selected Bluetooth out of the technologies(Bluetooth, SWAP(SharedWireless Access Protocol), IrDA(Infra Red Data Association), WLAN(Wireless Local Area Network)) which was developed for local data communication and set up simple experimental system for wireless data transfer and server and client program for wireless data transfer was wrote. We successfully transferred some data wirelessly with this program.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.1 s.45
• /
• pp.137-144
• /
• 2007

Advances in networking technology digital media, and codecs have made it possible for the Internet evolves into a Broadband convergence Network (BcN) and provides various services including Voice over Internet Protocol (VoIP) and IPTV over their high-speed IP networks. In order for the Internet to make a profit as traditional Public Switched Telephone Network (PSTN), it must provide high qualify VoIP services. Therefore, real time qualify measurement framework is the most important requisite to provide VoIP service. For this, IETF (Internet Engineering Task Force) defined RTCP-Extended Reports (RTCP-XR) that extend RTCP (Real-Time Transport Protocol Control Protocol). However, procedure and method tot actually VoIP qualify measurement did not recommended nothing but defined item to measure voice quality. Our objective in this paper is to describes a practical measuring framework for end-to-end QoS of switched voice packet in an IP environment. It includes concepts as well as step-by-step procedures for measuring packetized voice streams. It also proposes new formats that extend RTCP-XR's concept.

• ETRI Journal
• /
• v.26 no.1
• /
• pp.27-37
• /
• 2004

The architecture in a differentiated services (DiffServ) network is based on a simple model that applies a per-class service in the core node of the network. However, because the network behavior is simple, the network structure and provisioning is complicated. If a service provider wants dynamic provisioning or a better bandwidth guarantee, the differentiated services network must use a signaling protocol with QoS parameters or an admission control method. Unfortunately, these methods increase the complexity. To overcome the problems with complexity, we investigated scalable dynamic provisioning for admission control in DiffServ networks. We propose a new scalable $qDPM^2$ mechanism based on a centralized bandwidth broker and distributed measurement-based admission control and movable boundary bandwidth management to support heterogeneous QoS requirements in DiffServ networks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.1
• /
• pp.113-120
• /
• 2015

Network type distributed control system uses a communication line which is named the BUS to exchange a data among the sub-systems. Usually, on the bus, only one data must be exited at one time, so the control algorithm to prevent collision or to manage a priority of data is important. Including CAN Protocol, many kind of FieldBus which are used for distributed control system, prevent data collision by controlling transmission time. But, a system which have to make a control signal or get a data from a sensor at fixed time will be met a problem when it is composed by using a network type distributed control structure. In this paper, some of these cases will be discussed and solutions be proposed for preventing a data collision. Also, using Arago Disk System which have a structure for inner loop control, the validity of the proposed methods will be verified.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.3
• /
• pp.196-203
• /
• 2003

Recent increase in accessibility to the internet makes it easy to use the internet-connected devices. The internet could allow any user can reach and command any device that is connected to the network. But these teleoperation systems using the internet connected device have several problems such as the network time delay, data loss and development cost of an application for the communication with each other. One feasible solution is to use local and external network line for the network time delay, transmission control protocol for data loss and Java language to reduce the development period and cost. In this study, web-based remote control system using Java language is newly proposed and implemented to a pneumatic servo control system to solve the time delay, data loss and development cost. We have conducted several experiments using pneumatic rodless cylinder through the internet and verified that the proposed remote control system was very effective.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.11a
• /
• pp.413-418
• /
• 2000

For Pneumatic system control, we need a data transmission system with high speed and high realibility for information interchange between main computer and solenoid valves and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition we developed a communication protocol for construction of RS-485 based multidrop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is possible up to 1,000m without using repeater. In addition, the system developed in this research is proved to be used easily for extension of a communication network because of its module structure.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.2
• /
• pp.123-131
• /
• 2009

Process Control Systems (PCSs) or Supervisory Control and Data Acquisition (SCADA) systems have recently been added to the already wide collection of wireless sensor networks applications. The PCS/SCADA environment is somewhat more amenable to the use of heavy cryptographic mechanisms such as public key cryptography than other sensor application environments. The sensor nodes in the environment, however, are still open to devastating attacks such as node capture, which makes designing a secure key management challenging. Recently, Nilsson et al. proposed a key management scheme for PCS/SCADA, which was claimed to provide forward and backward secrecies. In this paper, we define four different types of adversaries or attackers in wireless sensor network environments in order to facilitate the evaluation of protocol strength. We then analyze Nilsson et al. 's protocol and show that it does not provide forward and backward secrecies against any type of adversary model.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1127-1131
• /
• 2005

One of problems in industries is an installation for an automation system device such sensor, transducer, controller, and so on those are located in different areas. Such problem makes a difficulty for maintenance and installation. The aim of this research attempts to design a high performance controller with remote devices. One attractive is to group near devices in near place together to centralizes control. This paper presents network device groups distributed through digital and analog Remote Terminal Unit (RTUs). Such devices are centralized by computer or PLC control and communicated with similar protocol through serial bus. Our scheme, there are many advantages such as, saving both time and cost,convenience compared to other ways.

• The KIPS Transactions:PartC
• /
• v.9C no.4
• /
• pp.523-530
• /
• 2002

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. PON architecture is very simple but it requires MAC protocol for control of upstream traffic. This paper proposes a MAC protocol for a broadband access network using an ATM Passive Optical Network supporting CBR/rtYBR, nrtYBR, UBR and ABR traffic. For the proposed MAC scheme, we present grant field format, minislot format, and bandwidth allocation algorithm. From the simulation result, we have confirmed that our proposed scheme can reduce the average cell delay in comparison to that of conventional MAC schemes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.353-356
• /
• 2001

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. PON architecture is very simple but it requires MAC protocol for control of upstream traffic. This paper proposes a MAC protocol for a broadband access network using an ATM Passive Optical Network supporting CBR/rtVBR, nrtVBR, UBR and ABR traffic. For the proposed MAC scheme, we present grant field format, minislot format, and bandwidth allocation algorithm. from the simulation result, we have confirmed that our proposed scheme ran reduce the average tell delay in comparison to that of conventional MAC schemes.