• KIPS Transactions on Computer and Communication Systems
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• v.3 no.5
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• pp.141-150
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• 2014

In recent years, because of the development of ubiquitous technology in healthcare research is actively progress. Especially, healthcare service area is change to home for the elderly or patients from hospital. The technology to identify residents in a home is crucial for smart home application services. However, existing researches for resident identification have several problems. In this case, residents are needed to attach of various sensors on their body. Also relating private life, it is difficult to apply to resident's environment. In this paper, we used constraint-free sensor and unconscious sensor to solve these problems and we limited using of sensor and indoor environment in the way of working economical price systems. The way of multi-resident identification using only these limited sensors, we selected elements of personal identifications and suggested the methods in giving the weight to apply these elements to systems. And we designed the SABA mechanism to tract their location and identify the residents. It mechanism can distinguish residents through the sensors located each space and can finally identify them by using the records of their behaviors occurred before. And we applied the mechanism designed for applications to approve this location tracking system. We verified to the location tracking system performance according to the scenario.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.43-53
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• 2023

In this detailed and comprehensive study, our primary focus has been placed on accurately gauging the number of visitors and their real-time locations in commercial spaces. Particularly, in a real cafe, using security cameras, we have developed a system that can offer live updates on available seating and predict future congestion levels. By employing YOLO, a real-time object detection and tracking algorithm, the number of visitors and their respective locations in real-time are also monitored. This information is then used to update a cafe's indoor map, thereby enabling users to easily identify available seating. Moreover, we developed a model that predicts the congestion of a cafe in real time. The sophisticated model, designed to learn visitor count and movement patterns over diverse time intervals, is based on Long Short Term Memory (LSTM) to address the vanishing gradient problem and Sequence-to-Sequence (Seq2Seq) for processing data with temporal relationships. This innovative system has the potential to significantly improve cafe management efficiency and customer satisfaction by delivering reliable predictions of cafe congestion to all users. Our groundbreaking research not only demonstrates the effectiveness and utility of indoor location tracking technology implemented through security cameras but also proposes potential applications in other commercial spaces.

• Korean Management Science Review
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• v.29 no.2
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• pp.79-90
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• 2012

Focusing on the rapid market penetration of smart phones, the importance of LBS (Location Based Service) is drastically increased. However, traditional GPS method has critical weakness caused by limited availability, such as indoor environment. WPS is newly attractive method as a widely applicable positioning method. In WPS, RSSI (Received Signal Strength Indication) data of all Wi-Fi APs (Access Point) are measured and stored into a huge database. The stored RSSI data in database make single radio fingerprint map. By the radio fingerprint map, we can estimate the actual position of target point. The essential factor of radio fingerprint database is data integrity of RSSI. Because of millions of APs in urban area, RSSI measurement data are seriously contaminated. Therefore, we present the unified filtering method for RSSI measurement data. As the results of filtering, we can show the effectiveness of suggested method in practical positioning system of mobile operator.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.53-59
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• 2005

It is very dongerous for ship‘s fire which occurs from navigating because of it will not be able to expect fire fighting from land so that handle with the oneself to control. Additionally, in the case of passenger ship is more serious for the reason of not only the property damage but also large life accident can be occurred continuously. When the fire occurs, the many smoke to occur simultaneously as well as the heat from combustion process and the poisonous smoke is brought the life damage as the death from suffocation The purpose of this study is to examine the smoke movement characteristics in the ship's indoor spaces with fire size and location An experimental study was carried out with two sized of fires and three typed of fire source locations. As the results, the smoke and heat diffusion characteristics Ms been showed the most quick rise curve in the case of comer type fire.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.167-173
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• 2005

It is very dangerous for ship‘s fire which occurs from navigating because of it will not be able to expect fire fighting from land so that handle with the oneself to control. Additionally, in the case of passenger ship is more serious for the reason of not only the properly damage but also large life accident can be occurred continuously. When the fire occurs, the many smoke to occur simultaneously as well as the heat from combustion process and the poisonous smoke is brought the life damage as the death from suffocation. The purpose of this study is to examine the smoke movement characteristics in the ship's indoor spaces with fire size and location An experimental study was carried out with two sized of fires and three typed of fire source locations. As the result of it, the smoke and heat diffusion characteristics has been showed the most quick rise curve in the case of comer type fire.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3858-3874
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• 2021

As an essential part of the urban transportation system, precise perception of the traffic flow parameters at the traffic signal intersection ensures traffic safety and fully improves the intersection's capacity. Traditional detection methods of road traffic flow parameter can be divided into the micro and the macro. The microscopic detection methods include geomagnetic induction coil technology, aerial detection technology based on the unmanned aerial vehicles (UAV) and camera video detection technology based on the fixed scene. The macroscopic detection methods include floating car data analysis technology. All the above methods have their advantages and disadvantages. Recently, indoor location methods based on wireless signals have attracted wide attention due to their applicability and low cost. This paper extends the wireless signal indoor location method to the outdoor intersection scene for traffic flow parameter estimation. In this paper, the detection scene is constructed at the intersection based on the received signal strength indication (RSSI) ranging technology extracted from the wireless signal. We extracted the RSSI data from the wireless signals sent to the road side unit (RSU) by the vehicle nodes, calibrated the RSSI ranging model, and finally obtained the traffic flow parameters of the intersection entrance road. We measured the average speed of traffic flow through multiple simulation experiments, the trajectory of traffic flow, and the spatiotemporal map at a single intersection inlet. Finally, we obtained the queue length of the inlet lane at the intersection. The simulation results of the experiment show that the RSSI ranging positioning method based on wireless signals can accurately estimate the traffic flow parameters at the intersection, which also provides a foundation for accurately estimating the traffic flow state in the future era of the Internet of Vehicles.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.273-279
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• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.95-100
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• 2008

Conventional Earth Leakage Circuit Breakers (ELCBs) have defects of a breaking failure or a long breaking-time against parallel arc current. In this paper, breaking characteristics of conventional ELCBs were analyzed by simulation of parallel arc in a low-voltage indoor wiring system, and an air-core current sensor and a signal converter being most available for parallel arc detection were developed and applied to a conventional ELCB. The proposed tripped the ELCB regardless of the location of parallel arc. The breaking-time was in ranges of $1.74{\sim}8.3[ms]$ depending on the phase of arc generation, which is about 5 times as fast as conventional ELCBs with the breaking-time of 50[ms].

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.10
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• pp.920-929
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• 2014

Recently, embedded system which demand is explosively increasing in the fields of communication, traffic, medical and industry facilities, expands to cyber physical system (CPS) which monitors and controls the networked embedded systems. In addition, internet of things(IoT) technology using wearable devices such as Google Glass, Samsung Galaxy Gear and Sony Smart Watch are gaining attention. In this situation, Samsung Smart Home and LG Home Chat are released one after another. However, since these services can be available only between smart phones and home appliances, there is a disadvantage that information cannot be passed to other terminals without commercial global messaging server. In this paper, to solve above issues, we propose the structure of an indoor location network based on unit space, which prevents the information of the devices or each individual person from leaking to outside and can selectively communicate to all existent terminals in the network using IoT chatting. Also, it is possible to control general devices and prevent external leakage of private information.