• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.619-625
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• 2007

As low power, low cost wireless communication technology like Bluetooth, Zigbee, RFID has been put to practical use together with the wellbeing trend, the concern about ubiquitous health care has been greatly increased and u-Health is becoming one of the most important application in the sensor network field. Especially, development of the medical services to be able to cope with a state of emergency for solitary senior citizens and the aged in silver town is very meaningful itself and their needs are also expected to continuously increase with a rapid increase in an aging population. In this paper we demonstrate the feasibility of extracting accurate heart rate variability (HRV) measurements from photoelectric plethysmography(PPG) signals gathered by a ring type pulse oximeter sensor attached to the finger. For this, we made 2 types of ring sensor, that is reflective and pervious type, and developed the remote monitoring system which is able to collect HR data from ring sensor, analyze and cope with a state of emergency.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.4
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• pp.1914-1920
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• 2019

Background: Mobilization and cranio-cervical flexion exercise has been reported in reducing pain from cervical part and improving its motor function; also, has been represented that alleviate of neck pain and recover of neck muscles improve the normal gait performance. However, few studies have identified the effects of mobilization and exercise on pain and gait parameters with preceding issues. Objective: To examine the effects or changes of pressure pain threshold (PPT) and gait parameters in patients with chronic neck pain. Design: Cross-Sectional Clinical Trials Methods: Twenty patients with the history of neck pain (>3 months) performed the cervical mobilization and cranio-cervical flexion exercise. Gait parameters were assessed with wireless device and collected data were transmitted to the personal computer via Bluetooth. The PPT was measured posteroanterior direction at the prone position and the mean of subsequent three PPT measurements was used for the final analysis. Results: Both cervical central posteroanterior mobilization (CCPAM) (p<.000) and sling-based cranio-cervical flexion exercise (SBCCFE) (p<.000) group showed a significant increase in the PPT and the gait parameters, cadence (p<.023), was significantly increased in the CCPAM group, however slightly increased in the SBCCFE group. The comparison between the CCPAM and the SBCCFE groups after treatment did not show significant differences for the score on the PPT and gait parameters. Conclusions: This study suggests that CCPAM and SBCCFE increase PPT, cadence, and gait speed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.377-386
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• 2009

IPTV technology for providing multimedia content with high-speed is the network which combines existing network, multimedia and internet technology etc. But internet, broadcasting and web technologies which is now being used is not optimized to IPTV because the security problem between user who gets content service through mobile units and content server is not guaranteed. This paper proposes user certification mechanism between mobile device and content server to receive the service which the user for the content chooses by mobile device safely. The proposed mechanism uses the random number which user creates and certification token for preventing illegal user who uses other's service that already paid. Also the proposed protocol encrypts the delicate data like user's information or profile using shared-key between java card attached on user's mobile device and grant sewer and then prevents reply attack which happens often in wireless section and man-in-the-middle attack by MAC.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.118-129
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• 2008

This paper describes an IEEE 802.15.4-based hierarchical sensor network model for a VAWS(Vehicle Approach Warning System) which provides the drivers of vehicles approaching a sharp turn with the information about vehicles approaching the same turn from the opposite end. In the proposed network model, a tree-structured topology, that can prolong the lifetime of network is formed in a self-organizing manner by a topology control protocol. A simple but efficient routing protocol, that creates and maintains routing tables based on the network topology organized by the topology control protocol, transports data packets generated from the sensor nodes to the base station which then forwards it to a display processor. These protocols are designed as a network layer extension to the IEEE 802.15.4 MAC. In the simulation, which models a scenario with a sharp turn, it is shown that the proposed network model achieves a high-level performance in terms of both energy efficiency and throughput simultaneously.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.104-111
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• 2012

It is advantageous to avoid the handover to cell whose dwell time is short or can be ignored in terms of service continuity and average throughput. This paper proposes the handover scheme that is suitable for vehicle in order to improve the wireless Internet service quality. In the proposed scheme, the handover process continues to be learned before being modeled to Discrete-Time Markov Chain (DTMC). This modeling reduces the handover frequency by preventing the handover to cell that could provide service sufficiently to passenger even when vehicle passed through the cell but there was no need to perform handover. In order to verify the proposed scheme, we observed the average number of handovers, the average RSSI and the average throughput on various moving paths that vehicle moved in the given urban environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1207-1213
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• 2007

This paper has researched water supply facilities management using real-time water utility monitoring system based on USN(Ubiquitous Sensor Network) which is consisted of wireless sensors transferring waterworks facilities md treatment information about a valve-room and flowmeter-room of water supply installation. In the manholes, it was installed with flowmeter, pressure sensors, vibration sensors, Co-sensors, and hydro-thermograph sensors. These measurement values which are received by PDA are used for facilities operation on the spot safely and conveniently. It has also provided safe installation management via CDMA(Code Division Multiple Access) network which transfers data to remote servers to monitoring at a distance place. With safety management system of water supply facilities on USN technology convenience and safety is increased in real situation, and it is expected that we can supply clean water to people as much safer and more effective water supply installation management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2119-2124
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• 2008

An information-oriented basis in today's society has been changing fast, and the desire for connectivity has caused an exponential growth in wireless communication and sensor network. Sensor networks using RFID, in particular, have led this trend due to the increasing exchange of data in Ubiquitous such as the home RF, access control system, U-Healthcare, and Logistics information Systems. Also, the RFID when it applies a technique, is able to raise the stability of shipping as controling the mobile course and an entrance and exit of the crews an well as previously preventing an accident from shipping. In this paper, we designed and implemented personnel control system using UHF-RFID in vessels which shows through host PC reading and writing tag.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1665-1671
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• 2007

Mobile Ad hoc Networks (MANETs) refer to autonomous networks in which wireless data communications are established between multiple nodes in a given coverage area without a base station or centralized administration. Because of node mobility and limited battery life, the network topology may changes frequently. Selecting the most reliable path during route discovery process is important to improve performance in ad-hoc networks. In this study, we proposed an enhanced routing protocol based on AODV by monitoring variation of receiving signal strength. New metric function that consists of node mobility and hops of path is used for routing decision. From extensive experiments by using NS-2, The performance of the proposed routing scheme has been imp개ved by comparison to AODV protocol.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.9-17
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• 2019

As the IoT environment becomes more popular, the safety of the M2M environment, which establishes the communication environment between objects and objects without human intervention, becomes important. Due to the nature of the wireless communication environment, there is a possibility of exposure to security threats in various aspects such as data exposure, falsification, tampering, deletion and privacy, and secure communication security technology is considered as an important requirement. In this paper, we propose a new method for group key generation and exchange using trap hash collision hash in existing 'M2M communication environment' using hash collision, And a mechanism for confirming the authentication of the device and the gateway after the group key is generated. The proposed method has attack resistance such as spoofing attack, meson attack, and retransmission attack in the group communication section by using the specificity of the collision message and collision hash, and is a technique for proving safety against vulnerability of hash collision.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.728-737
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• 2019

In this study, the minimized on-board computer (OBC) module for integrated navigation is developed, which provides satellites' relative position information in formation flying and cluster operation situations. The scalability is considered to apply the user-selected wireless communication module and Global Positioning System (GPS) receiver for navigation, while considering to meet the structural design standard of nano-satellites. As a result of the product development and production, the processing speed of integrated navigation and real-time data synchronization is satisfied for cluster operation nano-satellites by using micro controller unit (MCU). From a heat/vacuum, vibration and radiation test, the OBC was confirmed to be operated in space environments. From these results, a mass production system of OBC was made which is a key part of development on satellite formation flying and cluster/constellation missions that the community demands are increasing.