• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.5
• /
• pp.129-136
• /
• 2012

Temperature of fresh concrete can be effectively used to predict the strength of concrete being cured and make an informed decision for stripping the molds. A hygrothermograph and thermo-couple sensors that require an extensive wiring have been applied to measure a temperature of concrete at the early stage of the curing process on site. However, these methods have limits to provide the temperature data in real time due to harsh working environment including frequent cutting of wires. Therefore, this study is aiming at developing a device based on wireless sensor network to measure the temperature of concrete being cured in formwork. The result showed that the wireless sensor with probe type thermistor which is developed had the same temperature data compared to the existed wire type thermistor, and we confirmed the temperature history of concrete in real time for 28 days throughout the gateway by wireless network that collects the temperature data measured from specimens in laboratory. Also, the network device for transmission can be easily separated from the probe sensor part and reused consistently. If the wireless sensor network device developed uses in the field, the temperature management of concrete will be systematically conducted from at the early stage of the curing, and especially be effective for cold weather concrete construction. In addition, it will contribute to the establishment of advanced quality control system for concrete and productivity of supervisors on site will be increased in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.745-748
• /
• 2006

With a home network, a device can dynamically join a home network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices. Devices can subsequently communicate with each other directly. Device discovery protocol defines how network services can be discovered on the network. In this paper, we propose the secure discovery method of devices that uses mutual authentication with symmetric key between devices. This method that we present distributes symmetric-key to home network devices by the home server. Using this key, mutual authentication is performed between home appliances. It enables any appliance under any middleware's control to securely communicate any other appliances.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.12B
• /
• pp.779-789
• /
• 2007

This paper presents an architecture of UPnP Bridge for interconnecting Non-lP devices with heterogeneous network interfaces to UPnP devices on UPnP networks. The proposed UPnP Bridge provides a Virtual UPnP device that performs generic UPnP Device's functionalities on behalf of Non-lP device. This paper defines 3 types of descriptions, Device Description, Message Field Description, and Extended UPnP Service Description in order to reduce the amount of effort required to connect a non-lP device with a new interface or message format to UPnP network. By these three types of descriptions and Message conversion module, developers for Non-lP devices can easily connect the devices to UPnP network without additional programming. So UPnP control point controls Non-lP devices as generic UPnP device. Some experiments validate the proposed architecture, which are performed on a test bed consisting of UPnP network the proposed bridge, and non-lP devices with CAN and RS232 interfaces.

• Journal of the Korea Convergence Society
• /
• v.8 no.2
• /
• pp.15-20
• /
• 2017

In this paper, Esp8266, Node.js, and TCP / IP socket communication are used to design a compact data integration device. This device is designed to configure server and client using Esp8266 module that supports Wifi connection and to support bidirectional data transmission using TCP / IP socket communication. The server is configured using the Node.js operating system, and the database is integrated using Mysql. The network is designed to have a separate IP address by assigning a private IP address to the router, such as a home network. This device can transmit data bidirectionally, store individual client data on the server side, and can check the flow of data transmitted bidirectionally through wire-shark, so that it can be used as a compact real-time data integration and convergence device.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.11
• /
• pp.1511-1517
• /
• 2018

Mobile Device-to-Device (D2D) caching networks can transmit multimedia data to users directly without passing through any network infrastructure by storing popular multimedia contents in advance that are popular among many mobile users at caching server devices (CSDs) in distributed manners. Thus, mobile D2D caching networks can significantly reduce backhaul traffic in wired networks and service latency time of mobile users. In this paper, we propose an efficient transmission scheme that can enhance the transmission efficiency of mobile D2D caching networks by using multiple CSDs that are caching the contents that are popular among mobile users. By sorting the multiple CSDs that are caching a content that mobile users want to receive according to their channel gains, the proposed scheme can reduce the complexity of algorithm significantly, compared to an optimal scheme based on Brute-force searching, and can also obtain much higher network transmission efficiency than the existing Blanket and Opportunistic transmission schemes.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.3
• /
• pp.253-259
• /
• 2003

This paper aims at developing remote control system to control and monitor distributed various devices such as UPS through internet. TCP/IP(Transmission Control Protocol/Internet Protocol) and UPS operated in a row are adopted for the network management protocol and the application device, respectively. For controlling and monitoring distributed devices in realtime, java-environment software is constructed. Also, HelloDevice, general-use interface controller between network device and applied device is proposed. Finally, serial communication such as RS-232C is used between controller and applied device.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.11
• /
• pp.1500-1506
• /
• 2020

In this paper, we study a scheduling problem based on reinforcement learning for overlay device-to-device (D2D) communication networks. Even though various technologies for D2D communication networks using Q-learning, which is one of reinforcement learning models, have been studied, Q-learning causes a tremendous complexity as the number of states and actions increases. In order to solve this problem, D2D communication technologies based on Deep Q Network (DQN) have been studied. In this paper, we thus design a DQN model by considering the characteristics of wireless communication systems, and propose a distributed scheduling scheme based on the DQN model that can reduce feedback and signaling overhead. The proposed model trains all parameters in a centralized manner, and transfers the final trained parameters to all mobiles. All mobiles individually determine their actions by using the transferred parameters. We analyze the performance of the proposed scheme by computer simulation and compare it with optimal scheme, opportunistic selection scheme and full transmission scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.05a
• /
• pp.187-191
• /
• 2003

This paper pertains to the embodiment of the CATV network devices, and Automatically Centralized device was embodied in order to solve the inefficiency of the existing passive device. The frequency bandwidth, which don't use the part of CATV on signal of video, using frequency bandwidth of the control and systemize in automatic distributive system, the communication which depends on two way of forward/backward communication and backward communication/materialize in the system of unification management of 9600bps using RS-232.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.98-100
• /
• 2007

DC Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, DC arc detection device is designed for the display of DC arc fault current which is occurred in the local electric network with DC Power. This DC arc is one of the main causes of electric fire. Arc fault in electrical network has the characteristics of low current, high impedance and low frequency. DC Arc current detection device is designed for the display of arc fault current which has the modified arc characteristics.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.3
• /
• pp.315-320
• /
• 1998

In this paper, we present the PID control method for the controlling flow rate of highly complicated nonlinear Left Ventricular Assist Device(LVAD) with pneumatically driven mock circulatory system. Beat Rate (BR), Systole-Diastole Rate (SDR) and flow rate are used as the main variables of the LVAD system. System modeling is completed using the neural network with input variables (BR, SDR, their derivatives, actual flow) and an output valiable(actual flow). Then, as the basis of this model, we perform the simulation of PID control to predict the performance and tendency of the system and control the flow rate of LVAD system using the PID controller. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated through computer simulation and experiments.