• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.750-757
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• 2011

Wireless Sensor Network is composed of a lot of sensor nodes that are densely deployed in a field. So generally this sensor nodes are spreaded using Helicopter or Fixed wing. Each node delivers own location and acquired information to user when it detects specific events. In this paper, we propose localization algorithm without range information in wireless sensor network using helicopter. Helicopter broadcasts periodically beacon signal for sensor nodes. Sensor nodes stored own memory this beacon signal until to find another beacon point(satisfied special condition). This paper develops a localization mechanism using the geometry conjecture(perpendicular bisector of a chord) to know own location. And the simulation results demonstrate that our localization scheme outperforms Centroid, APIT in terms of a higher location accuracy.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.257-263
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• 2012

Smart phones become popular all over the world recently. At the same time, demand of various additional services, such as SNS by utilizing low-cost reliable Wi-Fi network and position information, is expected to keep growing. In this paper, Implementation of SNS based on an Open Wi-Fi & Position Information was proposed. This service is achieved by constructing an Open Wi-Fi network based on a built AP access information database. And in order to provide durable connection in mobile environment, RSS detect AP switching module and mobile IP are utilized in the proposed service. Furthermore, with the utilization of GPS information of AP, AP providers could delivery various information such as advertisements, promotion events. In addition, it is possible for AP users to communicate with each other, thus a position information based SNS was also proposed in this paper.

• Particle and aerosol research
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• v.7 no.1
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• pp.21-30
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• 2011

The spatial distributions of air pollutants, in particular, ultrafine particles near traffic congestion roads at urban areas need to reduce human exposure levels for protecting public health. In this study, the number concentrations of ultrafine particles larger than 5 nm were measured every second during driving on the major roads of Nowon-gu, Seoul for 1.6 h using a mobile emission laboratory on October 5, 2010. The ultrafine particle number concentrations ranged from 7,009 to $265,600particles/cm^3$ with an average of $55,570particles/cm^3$, and these levels were comparable to concentrations of ultrafine particles larger than 3 or 7 nm on the arterial roads at urban areas in Los Angeles, USA and Zurich, Switzerland. It was frequently observed that the ultrafine particle number increased rapidly when vehicle speed was accelerated and it decreased sharply when vehicle speed was decelerated. The high peak events of ultrafine particle concentration larger than $200,000particles/cm^3$ were observed seven times during the measurement period. From the three repeated measurements during the short period of 50 min, it was concluded that the ultrafine particle number concentration on the road was significantly time-dependent. This on-road measurement approach can be utilized to manage vehicle-related air pollution in urban.

• KIISE Transactions on Computing Practices
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• v.21 no.4
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• pp.320-326
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• 2015

With the growing concern over frequent occurrences of criminal events, help-requesting mobile applications have drawn attention. However, existing applications solely focus on providing help-requesting services. Therefore, in this paper, we design and implement a help request and response process which allows users to request help by sending messages and locating their friends, acquaintances and even near-by application users, and to allow help be reached by forwarding messages. This application is composed of three parts: help-requesting, help-responding, and checking-status. This application is developed on the Android platform where we exchange users' longitude and latitude through web server communication. We conducted test to verify the effectiveness of the forwarding function, and it has been confirmed that 93.33% of subjects used the forwarding function to help users at risk.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.963-973
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• 2021

Based on the TPB(Theory of Planned Behavior), this study explores the physical education perceived by college students by applying the causal relationship (SEM) to life sports, participation intention, and participation behavior perceived by college students in the Covid-19 environment, and to provide basic data for predicting life sports events. For this, a total of 267 people were analyzed using the mobile program "Survey Monkey" according to the sample plan from December 1, 2020 to May 1, 2020. As a result of the study, it was found that the planned behavior theory had a statistically significant positive(+) correlation with the intention to participate in physical education. The planned behavior theory showed that there was a statistically significant positive(+) correlation with the life sports participation behavior. Lastly, the intention to participate in physical sports was found to have a statistically significant positive(+) correlation with participation in physical sports.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.3-13
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• 2006

As computing devices become ubiquitous and increasingly mobile, it becomes obvious that a synchronous and direct peer-to-peer communication model is not sufficient in distributed computing environment. Using an indirect event service instead of other traditional communication model has an advantage of decreasing the coupling of applications in a distributed environment and removing the need for many static dependencies. In this paper, we design and implement the secure event service for providing secure ubiquitous computing environment. The Secure Event Service implemented enables users to perform content-based event retrieval, and supports only eligible event comsumer and event producer can publish and receive events through the secure event service. SPKI/SDSI certificate is used for supporting authentication and authorization in the secure event service. In order to provide a content-based event retrieval, an asynchronous communication between event producers and consumers, and a disconnectedness support for mobile devices, we modify and expand the Javaspace package.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.628-636
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• 2021

This paper contains the implementation and performance evaluation results of a system that collects environmental data at the time when the wild animal intrusion occurred at farms and then predicts future wild animal intrusions through a machine learning-based Vector Autoregression(VAR) model. To collect the data for intrusion prediction, an IoT-based hardware prototype was developed, which was installed on a small farm located near the school and simulated over a long period to generate intrusion events. The intrusion prediction service based on the implemented VAR model provides the date and time when intrusion is likely to occur over the next 30 days. In addition, the proposed system includes the function of providing real-time notifications to the farmers mobile device when wild animals intrusion occurs in the farm, and performance evaluation was conducted to confirm that the average response time was 7.89 seconds.

• Atmosphere
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• v.31 no.5
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• pp.525-537
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• 2021

Black ices on road surfaces in winter tend to cause severe and terrible accidents. It is very difficult to detect black ice events in advance due to their localities as well as sensitivities to surface and upper meteorological variables. This study develops a methodology to detect the road sections vulnerable to black ice with the use of road surface temperature data obtained from a mobile road weather observation vehicle. The 7 experiments were conducted on the route from Nam-Wonju IC to Nam-Andong IC (132.5 km) on the Jungang Expressway during the period from December 2020 to February 2021. Firstly, temporal road surface temperature data were converted to the spatial data with a 50 m resolution. Then, the spatial road surface temperature was normalized with zero mean and one standard deviation using a simple normalization, a linear de-trend and normalization, and a low-pass filter and normalization. The resulting road thermal map was calculated in terms of road surface temperature differences. A road ice index was suggested using the normalized road temperatures and their horizontal differences. Road sections vulnerable to black ice were derived from road ice indices and verified with respect to road geometry and sky view, etc. It was found that black ice could occur not only over bridges, but also roads with a low sky view factor. These results are expected to be applicable to the alarm service for black ice to drivers.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1269-1273
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• 2010

Typically users prefer to manage and access personal photo collections taken from a cell phone based on events. In this paper we propose an event clustering algorithm that requires low computation cost with high accuracy supporting incremental operation. The proposed method is based on the statistical analysis of the elapsed interval of intra-event photos on the real sample data for the decision of an event boundary. We then incorporate both location and visual information for the ambiguous range to split with only temporal cue. According to test results, we show higher performance compared to existing general clustering approaches.

• Genomics & Informatics
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• v.5 no.4
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• pp.179-187
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• 2007

An increasing number of primate genomes are being sequenced. A direct comparison of repeat elements in human genes and their corresponding chimpanzee orthologs will not only give information on their evolution, but also shed light on the major evolutionary events that shaped our species. We have developed REPEATOME to enable visualization and subsequent comparisons of human and chimpanzee repeat elements. REPEATOME (http://www.repeatome.org/) provides easy access to a complete repeat element map of the human genome, as well as repeat element-associated information. It provides a convenient and effective way to access the repeat elements within or spanning the functional regions in human and chimpanzee genome sequences. REPEATOME includes information to compare repeat elements and gene structures of human genes and their counterparts in chimpanzee. This database can be accessed using comparative search options such as intersection, union, and difference to find lineage-specific or common repeat elements. REPEATOME allows researchers to perform visualization and comparative analysis of repeat elements in human and chimpanzee.