• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.471-478
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• 2003

Traditionally,, analysis, simulation and measurement have all been used to evaluate the performance of network protocols and functional entities that support mobile wireless service. Simulation methods are useful for testing the complex systems which have the very complicate interactions between components. To develop a mobile call simulator which is used to examine, validate, and predict the performance of mobile wireless call procedures must have the teletraffic model, which is to describe the mobile communication environments. Mobile teletraffic model is consists of 2 sub-models, traffic source and network traffic model. In this paper, we analyzed the network traffic data which are gathered from selected Base Stations (BSs) to define the mobile teletraffic model. We defined 4 types of cell location-Residential, Commercial, Industrial, and Afforest zone. We selected some Base Stations (BSs) which are represented cell location types in Seoul city, and gathered real data from them And then, we present the call rate per hour, cail distribution pattern per day, busy hours, loose hours, the maximum number of call, and the minimum number of calls based on defined cell location types. Those parameters are very important to test the mobile communication system´s performance and reliability and are very useful for defining the mobile network traffic model or for working the existed mobile simulation programs as input parameters.

• Land and Housing Review
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• v.14 no.4
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• pp.111-120
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• 2023

Indoor air quality has become increasingly important with the increase in time spent in residential environments, impact of external fine dust, yellow dust, and the post-COVID 19 pandemic. Residential mechanical ventilation plays a key role in addressing indoor air quality. The legal standard for residential air changes per hour in Korea is 0.5 ACH. However, there are no standards for the location of supply and return vents. This study atempts to analyze the impact of ventilation performance based on the location of supply and return vents. An experiment was conducted using the CO₂ tracer gas concentration decay method in a mock-up house set inside a large chamber to minimize external influences. The experimental results indicated that the commonly used combination of 2 supply and 2 return vents in living room spaces had a lower mean age of air than the combination of 1 supply and 2 return vents. Using multiple supply and return vents had lower mean age of air than using just 1 supply and 1 return vent.

• Journal of the Korean association of regional geographers
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• v.8 no.2
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• pp.216-228
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• 2002

This study analyzes the decision-making processes for university students to choose the location of their future houses in metropolitan area. Based on their intuitive judgment, the university students prefer the general criteria, transportation, facility, education and society, and economy in order. The Kendall coefficient of concordance W which determines the association among the rankings of the students' judgement on the importance of the general criteria is so low. It means that the students highly disagree their rankings of the importance of the general criteria. The rankings of the importance of the criteria like as transportation and education society are concentrated on a mean value, but those of the criteria like natural environment and economy are relatively dispersed. The students prefer the area between the center of Taegu-si center and its outskirts, the outskirts of Taegu-si, and the center of Taegu'si in order as an alternative location of their future house. From the specific criteria like the price of land and house, the student's preferences on the alternative locations of future house are varied as compared with those of the general criteria. According to a sensitivity analysis, the student's preference on the center of Taegu-si is increased, but that on the the outskirts of Taegu-si is decreased as the importance of facility and transportation factor is increased. On the contrary, the student's preference on the outskirts of Taegu-si is increased, but that on the center of Taegu-si is decreased as the importance of natural environments is increased.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.113-123
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• 2012

Recently, various attempts have been made to apply Intelligent Transportation System under various environments and conditions. Consequently, an accurate license plate recognition regardless of vehicle location and viewing angle is required. In this paper, we propose a novel license plate recognition system which exploits a) the format of license plates to remove false candidates of license plates and to extract characters in license plates and b) the characteristics of Hangul for accurate character recognition. In order to eliminate false candidates of license plates, the proposed method first aligns the candidates of license plates horizontally, and compares the position and the shape of objects in each candidate with the prior information of license plates provided by Korean Ministry of Construction & Transportation. The prior information such as aspect ratio, background color, projection image is also used to extract characters in license plates accurately applying an improved local binarization considering luminance variation of license plates. In case of recognizing Hangul in license plates, they are initially grouped according to their shape similarity. Then a super-class method, a hierarchical analysis based on key feature points is applied to recognize Hangul accurately. The proposed method was verified with high recognition rate regardless of background image, which eventually proves that the proposed LPR system has high performance regardless of the vehicle location or viewing angle.

• Korean Journal of Human Ecology
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• v.21 no.3
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• pp.597-609
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• 2012

The purpose of this study was to explore the characteristics, outcomes and successes associated with newly established rural villages founded by the Rural Village Development Policy in Korea. For this study, four operatives associated with development companies who successfully implemented rural villages with strong community function structures answered a semi-structured questionnaire on the developmental theme, location, preoperational resident meetings, and success factors of seven projects. The Questionnaire dealt with content analysis. The results of the study were as the follows. The operatives of the development companies identified locations, environments for economic activities, project themes and regular resident meetings as success factors. Barriers for successful rural village development policy were identified as inadequate regulation and lengthy administrative procedures. In particular, preoperational resident meetings were seen as an important success factor, requiring an organized and well-funded professional program.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.2
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• pp.106-116
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• 2012

The huge success of location-aware applications has called for the rapid development of an alternative positioning system to the global positioning system (GPS) for indoor localization based on existing technologies, such as 802.11 wireless networks. This paper proposes the Wireless MAC Processor Positioning System (WMPS), which is a localization system running on off-the-shelf 802.11 Access Points and based on the time-of-flight ranging of users' standard terminals. This paper proves through extensive experiments that the propagation delays can be measured with the accuracy required by indoor applications despite the different noise components that can affect the result: latencies of the hardware transreceivers, multipath, ACK jitters and timer quantization. Key to this solution is the choice of the Wireless MAC Processor architecture, which enables a straightforward implementation of the ranging subsystem directly inside the commercial cards without affecting the basic DCF channel access algorithm. In addition to the proposed measurement framework, this study developed a simple and effective localization algorithm that can work without requiring any preliminary calibration or device characterization. Finally, the architecture allows the measurement methodology to be adjusted as a function of the network load or propagation environments at the run time, without requiring any firmware update.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2193-2201
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• 2006

In related to mobile communication environment. Kesdogan and Pfitzmann[1,2,3] proposed solutions using temporary pseudonym identification, called TP(Temporary Pseudonym) to solve the problems concerning current locations of mobile users and exposure of their movements in the privacy aspect. After that, we proposed more improved method protecting mobile users from active attacks of network providers in [4]. But it is the case that mobile users are located in only home domain. As a more extended method. we propose new mobile terminated protocol protecting user privacy in case of moving from the home domain to the remote domain and analyze its security.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.1-6
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• 2017

Functionally Graded Materials (FGM) as advanced heterogeneous composite materials have a higher performance than a conventional composite or bimaterial composite under some severe environments. As a heterogeneous material, FGM is commonly used in spacecraft, defense, nuclear and automotive industries due to its excellent properties. The purposes of this study are to evaluate the stress distribution and crack behaviors by the multiscale simulation. FGM contains two or more than two materials that the composition is structured continuously. Two types of FGM model are suggested, which are created by arbitrary prediction of the volume fraction and the exponential function. Aluminum as the metal matrix constituent and silicon carbide as the ceramic particle constituent are structured gradually by two types and the three point bending test also estimated. Moreover, two kinds of crack location were introduced in order to get the influences of material property distribution on the stress intensity factor. From the results we found that the stress intensity factors are increased in the case from softer to stiffer material, while vice versa.

• Journal of the Korean Society for information Management
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• v.26 no.3
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• pp.169-188
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• 2009

The study proposed the algorithm for automatically summarizing the audio information from a video and then conducted an experiment for the evaluation of the audio extraction that was constructed based on the proposed algorithm. The research results showed that first, the recall and precision rates of the proposed method for audio summarization were higher than those of the mechanical method by which audio extraction was constructed based on the sentence location. Second, the proposed method outperformed the mechanical method in summary making tasks, although in the gist recognition task(multiple choice), there is no statistically difference between the proposed and mechanical methods. In addition, the study conducted the participants' satisfaction survey regarding the use of audio extraction for video browsing and also discussed the practical implications of the proposed method in Internet and digital library environments.

• Journal of the Korean housing association
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• v.28 no.1
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• pp.95-107
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• 2017

The purpose of the study is to analyze the planning characteristics of outdoor space in apartment complexes in terms of child-care environment. We selected 8 apartment complexes in Cheongju, within three years from construction, of small and medium-sized apartments ($60-85m^2$) where a large number of families with young children are presumed to reside in. As a result of the study, it was found that whereas the factors that can be quantified such as the floor height differences, the angles of ramps, and the number of the rest facilities are excellent, the qualitative part which cannot be easily quantified such as the location and direction of the rest facility and play materials should be improved a lot. And the following improvements were suggested; separating the pedestrian passage from the vehicle road in the main entrance of the complex, utilizing the piloti for infant caring, making the entrance area of apartment safe for pedestrians from vehicles, reallocating resting spaces, redesigning resting spaces safer to infants, building or reallocating existing booths at the stops of kindergarten buses, redesigning the square safer from vehicles with shades, making it possible for guardians to watch infants in playing field from the resting space, allocating natural environments essential for child development.