• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.151-156
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• 2020

A technology for calculating the position of a device is very important for users who receive positioning services, regardless of various indoor/outdoor or with/without any positioning infrastructure existence environments. One of the positioning resources widely used at present, LTE, is a typical infrastructure that can overcome the space limitation, however its positioning method based on the position of the LTE base station has low accuracy. A method of constructing a radio wave map of an LTE signal has been proposed as a method for overcoming the accuracy, but it takes a lot of time and cost to perform high-density collection in a wide area. In this paper, we describe a method of creating a high-density DB for the entire region by using vehicle-based partial collection data. To create a positioning database, we applied the idea of Generative Adversarial Network (GAN), which has recently been in the spotlight in the field of deep learning, and learned the collected data. Then, a virtually generated map which having the smallest error from the actual data is selected as the optimum DB. We verified the effectiveness of the positioning DB generation algorithm using the positioning data obtained from un-collected area.

• Journal of IKEEE
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• v.11 no.3
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• pp.100-107
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• 2007

One of the fundamental problems in wireless sensor networks is the efficient deployment of sensor nodes. The Fuzzy C-Means(FCM) clustering algorithm is proposed to determine the optimum location and minimum number of sensor nodes for the specific application space. We performed a simulation and a experiment using two rectangular and one L shape area. We found the minimum number of sensor nodes for the complete coverage of modeled area, and discovered the optimum location of each nodes. The real deploy experiment using sensor nodes shows the 94.6%, 92.2% and 95.7% error free communication rate respectively.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.2
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• pp.1-9
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• 2012

In this paper, we design and implement a DCS (Distributed Control System) based on dual field-bus for ship engine. For monitoring and controlling the condition of the ship engine, an implemented DCS is consisted of two-tier communication structure by using CAN (Controller Area Network) and MODBUS protocols. The first-tier is consisted of CAN protocol for sharing the condition of the ship engine by each implemented monitoring system. By using MODBUS protocol, the second-tier is used for communicating the monitoring data from an implemented DCS to AMS(Alarm Monitoring System). We verified and tested our scheme and implemented DCS by KR (Korea Register) technical rules through experimental tests.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.9-15
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• 2012

Multiple convenience features have been getting installed in recently released cars. However, the control of them has many uncomfortable matters yet. To resolve them, it is needed to study how to use easier the convenience features and control them remotely. Currently, wide range of convergence services are being released in various industries by using smartphone and smartphones with its state-of-the-art functions also are being released. In this paper, we design and implement smartphone-based applications for controling the vehicle's convenience features to control the vehicle convenience features with smartphone. To do this, we configure CAN (Controller Area Network) communication between the vehicle's various convenience features, and establish MCU (Micro Controller Unit) to control each feature. We also connect between the MCU and smartphones to make them available for the remote control. We can control lights, turn signals, audio, windows, air conditioner, and so on with the implemented smartphone-based control service of vehicle's convenience features using CAN remotely.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.91-96
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• 2005

Recetly, the term Personal Public Key Infrastructure (PKI) was introduced to supprot reliable and authenticated service in a Personal Area Network (PAN). However, traditional public key signature schemes and certificate status management are not suitable for a PAN environment since mobile devices that constitute the PAN have limited computing capability. In this paper, we propose a new scheme that efficiently provides signature generation and certificate status management for mobile devices. Based on hash chain technique, we intend to reduce computational overhead on signature generation, and further, to minimize communication overhead for managing certificate status.

• Journal of KIISE
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• v.45 no.3
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• pp.303-310
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• 2018

LoRaWAN(Long Range Wide Area Network) is a standard for low-power, long-range, low-speed communication as announced in the LoRa Alliance. LoRaWAN addresses the physical layer and medium access control layer and the technology used in the physical layer is referred to as LoRa. LoRa can be used for remote monitoring and remote control in maritime conditions. However, unlike land, marine environment is not only difficult to construct an infrastructure for service provision, but also difficult to analyze LoRa performance in maritime. In this study, we construct an infrastructure using cloud platform and analyze LoRa link performance in maritime conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1923-1930
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• 2012

'No-Automobile driving Day' is one of Special option of Automobile Insurance in Republic of Korea. It option is used a system for collect to automobile driving information. However, Its system gives discomfort to users of this system. A Discomfort of this system to users is the OBD device's(Personal Car Driving Check Device) installation. A frequent installation of this device provides this OBD device's breakage to the users of this system. In this paper, for a solve this problem, studied new system design to supplement the existing system using Smartphone and WPAN(Wireless Personal Area Network).

• Journal of Communications and Networks
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• v.13 no.2
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• pp.149-159
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• 2011

In this paper, we study the problem of how to design a medical-grade wireless local area network (WLAN) for healthcare facilities. First, unlike the IEEE 802.11e MAC, which categorizes traffic primarily by their delay constraints, we prioritize medical applications according to their medical urgency. Second, we propose a mechanism that can guarantee absolute priority to each traffic category, which is critical for medical-grade quality of service (QoS), while the conventional 802.11e MAC only provides relative priority to each traffic category. Based on absolute priority, we focus on the performance of real-time patient monitoring applications, and derive the optimal contention window size that can significantly improve the throughput performance. Finally, for proper performance evaluation from a medical viewpoint, we introduce the weighted diagnostic distortion (WDD) as a medical QoS metric to effectively measure the medical diagnosability by extracting the main diagnostic features of medical signal. Our simulation result shows that the proposed mechanism, together with medical categorization using absolute priority, can significantly improve the medical-grade QoS performance over the conventional IEEE 802.11e MAC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.872-875
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• 2005

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication, and can provides the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2(Privacy Key Management) protocol for authorization and key exchange between a MSS(Mobile Subscriber Station) and a BS(Base Station). This paper first reviews and studies overall security architecture of TTA HPi standard and IEEE 802.16e which supports mobility based on WMAN(Wireless Metropolitan Area Network) standard(IEEE 802.16)

• Journal of IKEEE
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• v.23 no.1
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• pp.159-163
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• 2019

The food service industry has been grown due to improvement of living standards. In addition, the demand for frozen food delivery is increasing day by day at online/offline and the refrigerated vehicles are used in most of these food distributions. One of the most important factors in a refrigerated car is to measure the temperature accurately. Conventional temperature recording systems are generally connected directly to temperature sensor modules. Since the temperature data are transmitted to the temperature recorder by using the electric wire, there is a disadvantage that the resistance error must be compensated according to the cable length. In this paper, we propose a method to correct errors due to cable resistance using digital processing and CAN (Controller Area Network) communication. We use PT-1000 platinum sensor to increase the accuracy of the temperature measurement.