• Journal of the Korean Mathematical Society
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• v.60 no.1
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• pp.143-165
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• 2023

For each connected and simply connected three-dimensional non-unimodular Lie group, we classify the left invariant Lorentzian metrics up to automorphism, and study the extent to which curvature can be altered by a change of metric. Thereby we obtain the Ricci operator, the scalar curvature, and the sectional curvatures as functions of left invariant Lorentzian metrics on each of these groups. Our study is a continuation and extension of the previous studies done in [3] for Riemannian metrics and in [1] for Lorentzian metrics on unimodular Lie groups.

• Korean journal of communication and information
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• v.27
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• pp.183-212
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• 2004

Mobile phone media have extended the terrain of human communication. Starting from the notion of McLuhan, this study suggests that the extension of human communication is a concept of multiple dimension, such as 'extension of function' and 'extension of ego' Mobile phone speed the pare and efficiency of life, but also allow more flexibility at business and professional levels as well as family and personal life. On the other hand, mobile phone is also conceived as a personality kit, that is as a symbol of user's identity. So we ran classify the mobile phone users as a typology of motivation. Group I, entitled 'hyper-coordination', has high instrumental and high expressive motivation. Group II(='instrumental') is high instrumental but low expressive. Group III(='expressive') is low instrumental and high expressive, and Group IV(='minimal') is low in both instrumentality and expressiveness of mobile phone use. Then would the hyper-coordination group have different usage pattern with the other groups? A sample of 482 university students completed survey questionnaire. , which states hyper-coordination group would most frequently make calls and text, and have largest extensity and variety of usage, is supported statistically. states that hyper-coordination group would have larger and deeper social network than the other groups. This hypothesis is also supported with statistics.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.388-395
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• 2013

PURPOSE. The purpose of this study was to estimate the effects of occlusal stability to identify action mechanisms of mouthguards, known to have a modulatory effect on limb muscle function. MATERIALS AND METHODS. This study included 20 male subjects to perform the isokinetic muscle tests and the Wingate anaerobic power test on both knee joints under five closed-mouth conditions: without or with 4 types of mouthguards with thickness of 2 mm based on premolar area: (1) full-coverage, (2) anterior partial-coverage, (3) right posterior partial-coverage, and (4) left posterior partial-coverage. The obtained results were subjected to One-way ANOVA with repeated measures, followed by post hoc test of the contrast method (${\alpha}$=.05). RESULTS. There was no significant difference between the closed position with and without a full-coverage mouthguard in all variables. However, significant differences were observed between with and without a partial-coverage mouthguard in muscular endurance during extension of the left knee, muscular power and endurance during flexion of the right knee. Additionally, significant differences were found between occlusal states with full- and partial-coverage mouthguards in muscular power and endurance during extension of the left knee. CONCLUSION. These findings indicate the elevation of vertical dimension by 2 mm or the inducement of occlusal stability had little effect on isokinetic muscle strength and anaerobic performance, while uneven distribution of occlusal force might have some positive effects.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.169-178
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• 2010

Objective. This study was conducted to observe the effect on appendage muscle strength according to increase in occlusal vertical dimension. Materials and methods. Ten males with a mean age of 21 were selected. The tested occlusal splints were made at the position of increased occlusal vertical dimension of 2mm,3.5mm and 5mm from the intercuspal position. Before and after wearing occlusal splints, the appendage muscle strength were tested by Cybex II dynamometer (Lumex Inc., Ronkonkoma, NY, USA). Results. Statistical analysis using the paired t-test revealed significant differences for flexion and extension of the hip, pronation of the forearm, internal rotation of the shoulder, external and internal rotation of the knee, and dorsiflexion and plantarflexion of the ankle (p<0.05). Conclusions. As the result of this study, we conclude that when occlusal vertical dimension was increased, most of mean muscular strength values were increased. Especially at the position of 3.5mm increased vertical dimension displayed the highest mean muscular strength value than other positions.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.79-87
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• 2011

Spatial perception and spatial structure that focus on psychological effects produce a real force through the medium of space that can control human actions, even their psychology. The job of understanding the characteristics and effects of architectural spaces that recognize the relationship between architecture and human beings, including the psychological dimension, is an alternative search for quality spaces that can increase the mutual relationship between space and human beings. This paper introduces two propositions called "space" and "psychology" in order to discover a meta-pattern connecting space and the human mind with the aim of systematizing that internal network and establishing a new architectural system concerning space and human beings. This paper also proposes a method of accessing physical spaces that can affect psychological states through a conceptual substitution called "extension," with the aim of discovering the implications inherent in such extensive relationships and proposing a methodology of organizing psychological spaces based on the characteristics of that extensive connection. The means of extensively connecting psychological spaces were classified into the three categories of memory system, sensory system, and motor system, and their corresponding extensive connection characteristics called "simultaneous relativity," "non-mediated immediacy," and "purification process" were also derived. These characteristics accelerate the changes in psychological intensity and function as principles that organize psychological space.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3E
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• pp.109-117
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• 2009

Identity recognition in real environment with a reliable mode is a key issue in human computer interaction (HCI). In this paper, we present a robust person identification system considering score-based optimal reliability measure of audio-visual modalities. We propose an extension of the modified reliability function by introducing optimizing parameters for both of audio and visual modalities. For degradation of visual signals, we have applied JPEG compression to test images. In addition, for creating mismatch in between enrollment and test session, acoustic Babble noises and artificial illumination have been added to test audio and visual signals, respectively. Local PCA has been used on both modalities to reduce the dimension of feature vector. We have applied a swarm intelligence algorithm, i.e., particle swarm optimization for optimizing the modified convection function's optimizing parameters. The overall person identification experiments are performed using VidTimit DB. Experimental results show that our proposed optimal reliability measures have effectively enhanced the identification accuracy of 7.73% and 8.18% at different illumination direction to visual signal and consequent Babble noises to audio signal, respectively, in comparison with the best classifier system in the fusion system and maintained the modality reliability statistics in terms of its performance; it thus verified the consistency of the proposed extension.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.61-73
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• 2007

The purpose of this study was to investigate the influence of the muscular endurance on the kinematic factors during a prolonged run. Subjects, 12 males, who were divided into three groups(lower group, general group, and in higher group) after measuring the lower limb's muscular endurance previously. They were asked toe run on the treadmill at 7.4km/h of speed. To analyze the kinematics parameters of the trunk during running, the ProReflex MCU Camera(Qualisys, Sweden) were used. All parameters were sampled from 5 minute, 40 minute, and 60 minute moments during running. An ANOVA with Repeated Measure was used to test the statistic significance between and within groups for all parameters determined with SPSS 11.0. Significance was defined as p<.05. The conclusions were as follows; There was significantly difference within(lapse of running time) groups in the take-off and minimum knee angle event of swing phase of the trunk flexion and extension. In conclusion, the muscular endurance affected on movement of the trunk during a prolonged run. In addition, it showed that there was significant difference in the energy consumption by lapse of running time. Therefore, it seems to be relationships between the muscular endurance and running efficiency.

• The Transactions of the Korea Information Processing Society
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• v.5 no.9
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• pp.2281-2293
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• 1998

Spatial objects in the space II odd hale been changed bl eitber non-spiltial operations or spatial operations. For example, their states arc changed by the following operation: changing their owners, changing their owner's address, installing new constructions, changing precincts, splitting, and merging, The conventional geographic information system(GIS), however, did not also manage their histoncal information cecause it handles the snapshot image of spatial ohjects in the world. In this paper we therelore propose a spatiotemporal data model which is ahle to not un]y manage the historical information of spatial objects but also, support their historical intemlgation by extending a time dimension and a historical pointer for SDE(Spatial Database Engine) spatial data model. Finally, the proposed spatiotemporal data model using a layered time extension are going to contribute to manage the history of spatial objects in the world and retrieve them.

• Journal of Agricultural Extension & Community Development
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• v.4 no.1
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• pp.57-72
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• 1997

Korean agriculture and rural sector has undergone a wide range of reform after the Uruguay Round. Major policy measure is to put finances of huge budget from tax payers since 1994 in preparation of the Rural Development Strategy and Reform Program. Both in the total amount and individual size of the subsidy and loan for eligible farmers and farmers group are large and drastically enormous than any other programs in the past. The strategy adopted was a bottom-up approach, Particularly in selecting the project with local autonomy. However, it has been still criticized as the form of centralized control of budget and decsion. In terms of the program effectiveness too, it is doubtful to judge that Korean agriculture is in a road to getting the international competetiveness as targeted. Since the local autonomy was started in 1995, the political structure has been settling in a way to be more locally institutionalized. Rural development policy, as the key point of economic and industrial dimension of local autonomy, should be initiated and practiced in real term by the local government. This paper, in this concern, in reviewing the past rural development prolicy and programs, discussed the necessary issues relevant to legal bases of land uses in Korea. Further, the direction of increasing local automous power of local government was discussed in the senses of budgetary control and decision. The power and budget should be allocated more to the rural development plans of local government in order to fulfilize integrated rural spatial development in this new era of globalization.

• Journal of Agricultural Extension & Community Development
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• v.21 no.1
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• pp.117-142
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• 2014

This study aims to analyzing economy of agricultural investment to the Ukraine based on survey and analysis of environment of agricultural investment to the Ukraine. The Ukraine had been used as a grain belt for Russia for some 60 years among CIS nations so that agricultural environment is excellent and capital investment on agricultural field is on the rise every year. Accordingly, agricultural investment to the Ukraine should be approached not only in economy but also in the dimension of diversification of foreign agricultural investment area and food security. And it is necessary to seek measures for both government and private body to make inroads into the country together.