• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.304-309
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• 2009

We tested the feasibility of measuring fat thickness using a miniaturized chip LED sensor module, testing 12 healthy female subjects. The module consisted of a single detector and four sources at four different source-detector distances (SD). A segmental curve-fitting procedure was applied, using an empirical algorithm obtained by Monte-Carlo simulation, and fat thicknesses were estimated. These thicknesses were compared to computed-tomography (CT) results; the correlation coefficient between CT and optical measurements was 0.932 for bicep sites. The mean percentage error between the two measurements was 13.12%. We conclude that fat thickness can be efficiently measured using the simple sensor module.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.149-151
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• 1998

Speed and position sensors require the additional mounting space, reduce the reliability, and increase the cost of motor. Various control algorithms have been proposed for the elimination of speed senor. This paper compares several schemes of MRAC for field-oriented control of induction motor without speed and flux sensors. These schemes are based on observing the fluxes, the counter EMF, and the instantaneous reactive power of motor. A review of these schemes of MRAC is presented. Then sensorless drives using each estimation method are compared through simulation and experiment.

• Convergence Security Journal
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• v.8 no.2
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• pp.27-34
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• 2008

In this paper, we designed and implemented mobile object automatic system based on senor networks for telematics. For developing this system, we gather the various sensing data through wireless communication method using zigbee sensor networks and analyze them in monitoring equipment. And we enable the driver to recognize the car state information on the whole by interfacing analyzed data to telematics unit. And, we implemented automatic controller that can control temperature and humidity in car automatically by actuating air conditioner based on the data that was monitored throughout temperature sensor, humidity sensor and brightness sensor based on sensor networks.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.17-24
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• 2016

In this paper, we introduce indoor localization technologies categorizing them into ON/OFF switch and senor based, wireless communication based, and image based technologies. Then we describe several representative techniques for each of them, emphasizing their strengths and weaknesses. We define important performance issues for indoor localization technologies and analyze recent technologies according to the performance issues. Our analyses show that ON/OFF switch based technologies are difficult to install, but accurate and not limited by light. Wireless communication technologies are not limited by light nor distance (space) and do not need additional device. Image based technologies do not need additional device but are limited by light, and their accuracies are affected by light. We believe that this paper provide wise view and necessary information for recent indoor localization technologies.

• Journal of Information Processing Systems
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• v.8 no.4
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• pp.589-602
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• 2012

With the increasing demand for real time applications in the Wireless Senor Network (WSN), real time critical events anticipate an efficient quality-of-service (QoS) based routing for data delivery from the network infrastructure. Designing such QoS based routing protocol to meet the reliability and delay guarantee of critical events while preserving the energy efficiency is a challenging task. Considerable research has been focused on developing robust energy efficient QoS based routing protocols. In this paper, we present the state of the research by summarizing the work on QoS based routing protocols that has already been published and by highlighting the QoS issues that are being addressed. The performance comparison of QoS based routing protocols such as SAR, MMSPEED, MCMP, MCBR, and EQSR has also been analyzed using ns-2 for various parameters.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.177-180
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• 2008

There are many application areas of sensor networks, such as surveillance, hospital monitoring, and home network. These are dependent on the secure operation of networks, and will have serious outcome if the networks is injured. An adversary can inject false data into the network through the compromising node. Ye et al. proposed a statistical en-route filtering scheme (SEF) to detect such false data during forwarding process. In this scheme, it is important that the choice of the threshold value since it trades off security and overhead. This paper presents an adaptive threshold value determining method in the SEF using fuzzy logic. The fuzzy logic determines a security distance value by considering the situation of the network. The Sensor network is divided into several areas by the security distance value, it can each area to uses the different threshold value. The fuzzy based threshold value can reduce the energy consumption in transmitting.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.387-389
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• 2003

Rational function model (RFM) is a universal sensor model for remote sensing image restitution. It is able to substitute for models of all known sensors. In this paper, RFM generation by CCD linear image models is described in detail. A principle of RFM-based 3D reconstruction and its implementation in JX4 DPW is also described. Experiments using IKONOS and SPOT5 images are carried out on JX4 DPW. Results show that RFM generated is feasible for photogrammetric restitution of CCD linear images.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.11-17
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• 2019

In this paper, we propose a method to recognize the moving direction in the indoor environment by using the sensing system equipped with passive infrared (PIR) sensors and a deep learning algorithm. A PIR sensor generates a signal that can be distinguished according to the direction of movement of the user. A sensing system with four PIR sensors deployed by $45^{\circ}$ increments is developed and installed in the ceiling of the room. The PIR sensor signals from 6 users with 10-time experiments for 8 directions were collected. We extracted the raw data sets and performed experiments varying the number of sensors fed into the deep learning algorithm. The proposed sensing system using deep learning algorithm can recognize the users' moving direction by 99.2 %. In addition, with only one PIR senor, the recognition accuracy reaches 98.4%.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.498-500
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• 2013

This paper presents a system design which allows monitoring and control of office electrical equipments and devices using senor network through the use of 3G network. The system uses SMS and Email protocols by smart phones to pass information and can be utilized in many scenarios and variety of parameters in which monitoring is desired. The combination of sensors, algorithms and web service are used to generate useful information efficiently and at low cost for the user connected to internet. The information passed is independent of the location of the office users and therefore effective information transfer is achieved from which users can monitor and perform necessary actions to the situations back in the office.

• Journal of Sensor Science and Technology
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• v.30 no.1
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• pp.36-41
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• 2021

The motivation of this paper is to easily analyze the properties of nondispersive infrared gas sensor that has more than two different optical path length and to suggest the criterion and definition of infrared light absorbance in order to minimize the measurement errors. With the output voltage ratios and the normalized derivatives of infrared ray (IR) absorbance, when the normalized derivatives of IR absorbance decreases from 0.28 to 0.10, the lower and higher limits of errors were decreased from -5.62% and 2.39% to -4.27% and 2.78%. When the normalized derivatives of IR absorbance were 0.10, the output voltage could be partitioned into two regions with one exponential equation and the temperature compensation error was less than 5%.