• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.6
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• pp.287-293
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• 2017

Sometimes, it is impossible to install a sensor on a certain location of a structure due to the size of a structure or poor surrounding environments. Even if possible, sensors can be frequently malfunctioned or improperly operated due to lack of adequate maintenance. These kind of problems are solved by the virtual sensing methods in various engineering fields. Virtual sensing technology is a technology that can measure data even though there is no physical sensor. It is expected that this technology can be also applied to the construction field effectively. In this study, a virtual sensing technology based on ARX model is proposed. An ARX model is defined by using the simulated data through a structural analysis rather than by actually measured data. The ARX-based virtual sensing model can be applied to estimate unmeasured response using a transfer function that defines the relationship between two point data. In this study, a simulation and experimental study were carried out to examine the proposed virtual sensing method with a laboratory test on a cable-stayed model bridge. Acceleration measured at a girder is transformed to estimate a cable tension through the ARX model-based virtual sensing.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.849-851
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• 2003

A location-based service or LBS in a cellular telephone network is a service provided to the subscriber based on his current geographic location. This position can be known by user entry or a GPS receiver that he carries with him, but most often the term implies the use of a function built into the cell network that uses the known geographic coordinates of the base stations through which the communication takes place. One implication is that knowledge of the coordinates is owned and controlled by the network operator, and not by the end user. Location utility service provides two kinds of functions, geocoder and reverse geocoder. Geocoder converts an address into a coordinate and reverse geocoder changes a coordinate into an address. Because location utility service is the first step to progress LBS, various servises such as directory, routing, presentation, and etc require to access that. In this paper, we will describe the architecture of LBS platform and the concept and the role of location utility service.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.659-662
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• 2005

Recently, the need for LBS (Location Based Services) is increasing with the rapid growth of the location measurement units, mobile devices, and communication technologies. Especially, wireless carriers are concentrating on LBS since it is regarded as so-called 'killer application' among wireless data services. Although LBS give us convenience and useful information, its use also raises privacy issues. There are quite possibilities that the people's locations are tracked by location measurement units while people do not recognize the existence of the units. To protect a person's location information, lawful and technical aspects should be considered. In this paper, we explain issues, regulations, standards, and platforms related to the protection of the location information. Finally, we suggest the architecture of a platform complying with the regulations and standards. It considers various issues not covered in other studies.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.67-73
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• 2014

When a mobile robot performs in unknown environments, a location identification is an essential task. In this paper, we propose a location identification system that uses a sensor space without additional devices on the robot. Also the sensor space consists of a matrix of CDS sensor; when a robot was positioned on the CDS sensor, we can estimate the coordinate of the location by sensing a light. Based on KS illumination standard, experiments are performed in various environments. By evaluating the experimental results, we can show that the proposed system can be applicable to the location identification system of a moving robot.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.555-557
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• 2003

Location-based services allow consumers to receive services based on their geographic location data. For example, businesses can provide information to find traffic facility, public restaurant, a hospital, and a station based on the consumer’s location at a particular moment. Also, they wish to grasp a accurate location based service in mobile device or PDA. So, this paper shows that presentation service offers a base-map to be overlaid OpenLS (Open Location Services)’s directory service, route determination service, geocode and reverse-geocode service. The presentation service is the portrayal of a map and portrayal of feature as map overlays.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2038-2057
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• 2017

Gaussian learning is a new technology in the computational intelligence area. However, this technology weakens the learning ability of a particle swarm and achieves a lack of diversity. Thus, this paper proposes a vector Gaussian learning strategy and presents an effective approach, named particle swarm optimization based on vector Gaussian learning. The experiments show that the algorithm is more close to the optimal solution and the better search efficiency after we use vector Gaussian learning strategy. The strategy adopts vector Gaussian learning to generate the Gaussian solution of a swarm's optimal location, increases the learning ability of the swarm's optimal location, and maintains the diversity of the swarm. The method divides the states into normal and premature states by analyzing the state threshold of the swarm. If the swarm is in the premature category, the algorithm adopts an inertia weight strategy that decreases linearly in addition to vector Gaussian learning; otherwise, it uses a fixed inertia weight strategy. Experiments are conducted on eight well-known benchmark functions to verify the performance of the new approach. The results demonstrate promising performance of the new method in terms of convergence velocity and precision, with an improved ability to escape from a local optimum.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.120-127
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• 2019

Medium-scale levee experiments were performed to monitor the infiltration and failure of levee body by applying fiber optic temperature sensing. In this study, bio-polymer soil was spread in the levee slope to increase the strength and intensity. Therefore, the infiltration and failure by overflows were produced in a different way compared to general soil type of levees. This was also observed in the experiment data for temperature changes monitored by fiber-optic distributed temperature sensing system. Through the analysis of temperature changes at specific location by time, the location and initiation time for physical changes and infiltration in levee body could be identified based on temperature variation. In this experiment, the time of rapid changes in temperature was ahead in the inland slope rather than the forceland slope. It was corresponding to the levee failure sequence of first inland slope failure and then the forceland slope failure.

• Journal of Information Processing Systems
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• v.14 no.4
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• pp.948-960
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• 2018

Many mobile sensing frameworks have been developed to help researcher doing their mobile sensing research. However, energy consumption is still an issue in the mobile sensing research, and the existing frameworks do not provide enough solution for solving the issue. We have surveyed several mobile sensing frameworks and carefully chose one framework to improve. We have designed an adaptive sampling module for a mobile sensing framework to help solve the energy consumption issue. However, in this study, we limit our design to an adaptive sampling module for the location and motion sensors. In our adaptive sampling module, we utilize the significant motion sensor to help the adaptive sampling. We experimented with two sampling strategies that utilized the significant motion sensor to achieve low-power consumption during the continuous sampling. The first strategy is to utilize the sensor naively only while the second one is to add the duty cycle to the naive approach. We show that both strategies achieve low energy consumption, but the one that is combined with the duty cycle achieves better result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8C
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• pp.713-719
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• 2010

Collaborative spectrum sensing has been found to be an effective means for detecting the activity of primary users in a fading environment. Most previous works on collaborative spectrum sensing are based on the assumption that the local spectrum sensing decisions of secondary users are statistically independent. However, it may not hold in some practical situations. In this paper, we consider a cognitive radio network where the local spectrum sensing decisions of secondary users are statistically correlated with the same level of correlation if they are next to each other in location and statistically independent, otherwise. Then, for the system, we analyzed the performance of the collaborative spectrum sensing with the AND and the OR fusion rules and found that the scheme with the AND fusion rule performs better than the one with OR fusion rule when the degree of correlation is significant.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.163-167
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• 2002

Recently, owing to performance elevation of telecommunication technology, increase of wireless internet's subscriber and diffusion of wireless device, Interest about LBS (Location Based Service) which take advantage of user's location information and can receive information in concerning with user's location is increasing rapidly. So, MOMS (Moving Object Management System) that manage user's location information is required compulsorily to provide location base service. LBS of childhood such as service to find a friend need only current location, but to provide high-quality service in connection with Data Mining, CRM, We must be able to manage location information of past. In this paper, we design distributed manage system to insert and search Moving Object in a large amount. It has been consisted of CLIM (Current Location Information Manager), PLIM (Past-Location Information Manager) and BLIM (Distributed Location Information Manager). CLIM and PLIM prove performance of searching data by using spatiotemporal-index. DLIM distribute an enormous amount of location data to various database. Thus it keeps load-balance, regulates overload and manage a huge number of location information efficiently.