• Hwankyungkyoyuk
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• v.25 no.1
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• pp.15-24
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• 2012

The goal of this study, as an effort to reduce national greenhouse gas (GHG) emissions, is to calculate the carbon footprint of students based on the commute pattern of high school students in big (Seoul), middle (Suwon) and small (Icheon) size city. By conducting a survey, the commute pattern and method of students as well as students' carbon footprint were evaluated. As a result, the carbon footprint of the high school student in Icheon ($1.698kgCO_2$) had 2~3 times higher than student's carbon footprint in Seoul ($0.623kgCO_2$) and Suwon ($0.699kgCO_2$). One of the reasons for the different carbon footprint result between big and small city was whether the public pedestrian facilities and a bicycle path or not. Based on our research results, we pointed out the problems and suggested some ways to reduce carbon footprint of students.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.146-154
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• 2016

This paper presents methods to analyze the topological structures of the spaces composed of patches extracted from waveform signals, which can be applied to the classification of signals. Commute time embedding is performed to transform the patch sets into the corresponding geometries, which has the properties that the embedding geometries of periodic or quasi-periodic waveforms are represented as closed curves on the low dimensional Euclidean space, while those of aperiodic signals have the shape of open curves. Persistent homology is employed to determine the topological invariants of the simplicial complexes constructed by randomly sampling the commute time embedding of the waveforms, which can be used to discriminate between the groups of waveforms topologically.

• Journal of the Korean Mathematical Society
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• v.53 no.5
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• pp.1037-1056
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• 2016

In this paper, we define the concepts of commute proximally, dominate proximally, weakly dominate proximally, proximal generalized ${\varphi}$-contraction and common best proximity point in probabilistic Menger space. We prove some common best proximity point and common fixed point theorems for dominate proximally and weakly dominate proximally mappings in probabilistic Menger space under certain conditions. Finally we show that proximal generalized ${\varphi}$-contractions have best proximity point in probabilistic Menger space. Our results generalize many known results in metric space.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.291-299
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• 2016

This paper raises a question of whether a simple periodic phenomenon is associated with the topology and provides the convincing answers to it. A variety of music instrumental sound signals are used to prove our assertion, which are embedded in Euclidean space to analyze their topologies by computing the homology groups. A commute time embedding is employed to transform segments of waveforms into the corresponding geometries, which is implemented by organizing patches according to the graph-based metric. It is shown that commute time embedding generates the intrinsic topological complexities although their geometries are varied according to the spectrums of the signals. This paper employs a persistent homology to determine the topological invariants of the simplicial complexes constructed by randomly sampling the commute time embedding of the waveforms, and discusses their applications.

• Kyungpook Mathematical Journal
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• v.11 no.2
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• pp.173-183
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• 1971

• Communications of the Korean Mathematical Society
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• v.13 no.2
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• pp.317-336
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• 1998

We study real hypersurfaces of a complex space form such that the Jacobi operator with respect to the structure vector field and the structure tensor $\phi$ on the real hypersurface commute.

• Kyungpook Mathematical Journal
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• v.59 no.2
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• pp.203-207
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• 2019

The commutativity degree of a finite group is the probability that two randomly chosen group elements commute. In this paper we give a sharp upper bound of commutativity degree of nonabelial groups in terms of their order.

• Bulletin of the Korean Mathematical Society
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• v.58 no.1
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• pp.47-58
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• 2021

In this article, we completely determine the rings for which every element is a sum of a nilpotent and three tripotents that commute with one another. We discuss this property for some extensions of rings, including group rings.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.2
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• pp.1-9
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• 2018

Currently, the record of part-timer is mainly written in handwriting or using excel work schedule, paper work recorder, and time attendance program using POS program. And, work table, commute records, paycheck are managed separately. Time-attendance information is not linked and is managed separately, and payment of wages is often not done accurately. And, it is difficult to pay the wages because it is not able to accurately grasp the state of attendance of part-timer. Therefore, it is necessary to have a transparent wage and work management system based on the trust between the owner and the part-timer. In this paper, we design a system that can perform real-time commute check using beacon, transparent wage management, wage calculation by automatic calculation, and smooth communication between owner and the part-timer. We have also implemented a store management mobile application using Android Studio 2.3, Eclipse, Android 5.1 and Beacon devices in a MySQL environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.857-865
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• 2016

This study analyzes 'willingness to have passenger cars' through perception survey about car use and possession. Social problems caused by increasing car use are serious. Because of the fact that 78.9% of registered vehicles are passenger cars and 75.3% of passenger cars are private cars, passenger cars are main reason of Social problems caused by using a car. So, we need to analyze the reason why people possess cars and need additional cars. Also we need to study about 'willingness to possess additional cars' through analysis of perception about car use and ownership. According to survey results, most households possess cars as means of commute, and most households need additional cars as means of commute to office, leisure, kids' commute to school and academy. Also we used Structural Equation Model to analyze car use and 'willingness to possess additional cars' according to ownership. Analysis results showed that car use is positively impacted by driving and usage perception, and negatively impacted by social problems such as parking, traffic congestion, traffic environment, and etc. Also, results showed that the number of car is positively impacted by usage perception, and negatively impacted by expenses. In case of 'willingness to have additional cars', is positively impacted by intention to use cars and negatively impacted by car ownerships. We think research results can be used as basic data to manage traffic demand.