• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.4
• /
• pp.601-608
• /
• 2023

Mobile robots are widely used in industries because mobile robots perform tasks in various environments. In order to carry out tasks, determining the precise location of the robot in real-time is important due to the need for path generation and obstacle detection. In particular, when mobile robots autonomously navigate in indoor environments and carry out assigned tasks within pre-determined areas, highly precise positioning performance is required. However, mobile robots frequently experience data missing in wireless communication environments. The robots need to rely on predictive techniques to autonomously determine the mobile robot positions and continue performing mobile robot tasks. In this paper, we propose an extended Kalman filter-based algorithm to enhance the accuracy of mobile robot localization and address the issue of data missing. Trilateration algorithm relies on measurements taken at that moment, resulting in inaccurate localization performance. In contrast, the proposed algorithm uses residual values of predicted measurements in data missing environments, making precise mobile robot position estimation. We conducted simulations in terms of data missing to verify the superior performance of the proposed algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.556-558
• /
• 2022

This paper proposes a CanSat system with a vehicle tracking function based on Jetson Nano, a high-performance small computer capable of operating artificial intelligence algorithms. The CanSat system consists of a CanSat and a ground station. The CanSat falls in the atmosphere and transmits the data obtained through the installed sensors to the ground station using wireless communication. The existing CanSat is limited to the mission of simply transmitting the collected information to the ground station, and there is a limit to efficiently performing the mission due to the limited fall time and bandwidth limitation of wireless communication. The Jetson Nano based CanSat proposed in this paper uses a pre-trained neural network model to detect the location of a vehicle in each image taken from the air in real time, and then uses a 2-axis motor to move the camera to track the vehicle.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.12
• /
• pp.1201-1208
• /
• 2016

Radio Frequency Identification (RFID) technology has a significant attraction throughout various industry sites, along with the development of wireless communication technologies. The typical applications of RFID include medical, logistics, and distribution, and, specially, it is effectively applied to non-contact environments, because it employs radio waves. Although, recently, construction cases of the RFID management systems for the inventory management of the construction materials have been increased, the related researches and experiments for the reused materials are not actively performed. In this paper, we propose the RFID system with the localization function for effectively managing the reuse of the construction materials, adding to the conventional inventory management system. The proposed system consists of a RFID reader unit and a receiver unit, and the location information of the material with the attached RFID tag is obtained by estimating the position of a RFID reader. The distance value for estimating the reader position is calculated using the Received Signal Strength Indicator (RSSI) value of Zigbee, and the performance evaluation of the proposed system is performed in the indoor space of $5m{\times}5m$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.4
• /
• pp.1849-1856
• /
• 2012

This paper proposes a method to track the center of pupil and perform the remote control for interface based on the substituted commands according to movements of pupil under smart phone environment. The proposed method, which is a remote control through the movement of eyes, may be helpful for the handicapped people or users who want a more convenient input method. A method based on webcam, which is representative one among the previous methods to track pupil of user, has a few limitations on distance and angle between location of user and webcam. However, this paper uses smart phone that is convenient to carry. The proposed method can perform the remote control through tracking of pupil using wireless network without any restriction on the location of users. Thus, the method is effectively applied for controlling the smart TV that should be controlled on the distance as well as the remote control for PC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.8C
• /
• pp.605-612
• /
• 2008

This paper researches the estimating location using repeater effect adjustment method in CDMA based system. Repeaters are commonly used by commercial and amateur radio operators to extend signals in the radio frequency range from one receiver to another. The repeater signals are increasing arrival time from base station to mobile station. So if we calculates the mobile station using repeater signals, the estimating position error is increased. However nobody researched about adjusting repeater effects. This paper proposes repeater effect adjustment algorithm. For adjusting repeater effects, we make the triangle using mobile station, reference base station and neighbor base station, and then detect the repeater effects using the triangle characteristic. The proposed method system showed the improved performance in estimating parameters and locating positions by computer simulations.

• Journal of the Korean Society for Railway
• /
• v.15 no.1
• /
• pp.29-36
• /
• 2012

This paper includes ATP(Automatic Train Protection) simulator development and ATP algorithm verification to allocate wayside and train-borne and verify ATP functions of communications based train control system. The train control system has some characteristics such as simple structure and high safety when wireless communication technology is applied to the train control system. Especially, vital functions can be performed with in wayside and train-borne ATP. However, different system can be realized because I/F contents vary in accordance with vital functional allocation of ATP. Drawing characteristics in accordance with wayside and train-borne functional allocation and drawing I/F details affected by such characteristics are needed accordingly. This paper includes ATP simulator development creating train location information by direct activation of an electric motor, verifies train safety distance control algorithm of ATP by functional allocation such as train movement authority and train speed limit to ATP, and draws any supplementation needed. Appropriate simulated environment for verify ATP algorithm and main factors that affect to the ATP function were confirmed.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.4
• /
• pp.69-78
• /
• 2009

DV-Hop algorithm is not accurate in estimating geographic location of nodes because the average size for one hop is calculated without considering of the positioning error. In this paper, a novel algorithm based on DV-Hop algorithm is proposed for the approach to estimating the average size of a hop by minimizing anchor's positioning error using Least Square Error with other anchors. Moreover, unknown nodes have their own average size for one hop to compensate for the location error of the unknown occurring as more than the minimum hop counts to the distance. Simulation results show that the proposed algorithm has more accuracy than DV-Hop has in positioning.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.1
• /
• pp.25-31
• /
• 2017

The indoor location based service proposed in the study was assigned to target a moving user. Positioning in the outdoor environment is accurate while using GPS. However, in an indoor environment, positioning is inaccurate and difficult. In order to overcome this, studies of various techniques for positioning based on wireless communication such as Wi-Fi, Zigbee and Bluetooth are being performed. The RSSI value and the delivery signal of the bluetooth beacon are measured according to the distance, and to a database. It was applied calculating the value for the average RSSI and the RSSI filtering feedback. Filtering is used to reduce the error of the RSSI values that are measured at long distance. When average and feedback filtering coefficient are set with 0.5, irregular and highly RSSI values are decreased. As the distance increases, the range of error is confirmed to have a reduction when using a distance calculation correction algorithm. Finally, when using the RSSI measurement results filtering, it corrects an unstable signal. Also, the distance correction algorithm is used to reduce a range of errors.

• Fashion & Textile Research Journal
• /
• v.18 no.6
• /
• pp.755-765
• /
• 2016

Recently, interest in monitoring health and sports is growing because of the emphasis on wellness, which is accelerating the development and commercialization of smart clothing for biosignal monitoring. In addition to exerciseeffect monitoring clothing that tracks heart rate and respiration, recently developed clothing makes it possible to monitor muscle balance using electromyogram (EMG). The electrode for EMG have to attached to an accurate location in order to obtain high-quality signals in surface EMG measurement. Therefore, this study develops monitoring clothing suitable for different types of human bodies and aims to extract suitable range of EMG according to movements in order to develop self-fitness monitoring clothing based on EMG measurement. This study identified and attached electrodes on six upper muscles and two lower muscles of ten males in their 20s. After selecting six main motions that create a load on muscles, the 8-ch wireless EMG system was used to measure amplitude value, noise, SNR and SNR (dB) in each part and statistical analysis was conducted using SPSS 20.0. As a result, the suitable range for EMG measurement to apply to clothing was identified as four parts in musculus pectoralis major; three parts in muscle rectus abdominis, two parts each in shoulder muscles, backbone erector, biceps brachii, triceps brachii, and musculus biceps femoris; and four part in quadriceps muscle of thigh. This was depicted diagrammatically on clothing, and the EMG-monitoring sensing locations were presented for development of self-fitness monitoring.

• The Journal of the Korea Contents Association
• /
• v.5 no.5
• /
• pp.85-91
• /
• 2005

Recently, home network system is providing more various services as home robot applied. A home robot not only basically controls home device but also services prevention of crimes, prevention of disasters through home monitoring and various entertainments while it navigates the autonomously based home network system. However, for the existing home robot to it is not easy to install all functions because the size of robot device becomes larger and the management of contents and applications executed becomes uneasy and has difficulties in adding new functions. Moreover many improvements are necessary for functioning of robot's location awareness. In this paper, we propose a more improved home robot system which uses resources of the robot efficiently as it divides the complicated operation of the robot among external digital device and adds new functions easily and recognizes the location of the robot by RFID.