• Journal of the Korean Mathematical Society
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• v.60 no.6
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• pp.1255-1302
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• 2023

We study various aspects of the structure and representation theory of singular Artin monoids. This includes a number of generalizations of the desingularization map and explicit presentations for certain finite quotient monoids of diagrammatic nature. The main result is a categorification of the classical desingularization map for singular Artin monoids associated to finite Weyl groups using BGG category 𝒪.

• Bulletin of the Korean Mathematical Society
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• v.61 no.3
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• pp.867-873
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• 2024

A pseudo-Riemannian solvmanifold is a solvable Lie group endowed with a left invariant pseudo-Riemannian metric. In this short note, we investigate the nilpotency of the Ricci operator of pseudo-Riemannian solvmanifolds. We focus on a special class of solvable Lie groups whose Lie algebras can be expressed as a one-dimensional extension of a nilpotent Lie algebra ℝD⋉n, where D is a derivation of n whose restriction to the center of n has at least one real eigenvalue. The main result asserts that every solvable Lie group belonging to this special class admits a left invariant pseudo-Riemannian metric with nilpotent Ricci operator. As an application, we obtain a complete classification of three-dimensional solvable Lie groups which admit a left invariant pseudo-Riemannian metric with nilpotent Ricci operator.

• Asia pacific journal of information systems
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• v.30 no.2
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• pp.228-251
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• 2020

This study attempts to examine the importance of social capital in customer service organizations and clarifies how translates into organizational performance through knowledge management activities. A survey was conducted with the customer service employees, and 256 questionnaires were used for an empirical analysis with smart partial least squares (PLS). The analysis found that relational capital had a positive effect on both the knowledge management components of knowledge sharing and knowledge conversion, while structural capital significantly influenced knowledge sharing. In addition, human capital positively affected knowledge conversion. Both knowledge sharing and knowledge conversion significantly influenced organizational performance. This study proposed a conceptual framework of social capital that influences organizational performance mediated by an organization's knowledge management activities. Based on the results, we suggest practical guidelines for managing social capital and recommend areas of improvement for customer organization's managers and employees.

• Journal of Fashion Business
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• v.12 no.2
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• pp.87-99
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• 2008

This study aims to classify lower trunk body types of Chinese men in their middle age (30s and 40s) and suggest the standard for them to design slacks pattern. Mollison's relation deviations were used to analyze the direct measurement items in this research compared to those of Size Korea 2004. Though Korean middle-aged men were higher in most items than Chinese counterparts, all items except mid-thigh circumference and side hip length were merely within the range of ${\pm}1\sigma$. According to the results of size classification by absolute values, factor analysis extracted to 2 factors(horizontal size of lower body and vertical size of lower body), and cluster analysis brought about 3 types(type1: tall and thin trunk (36.9%), type 2 : normal height and thick trunk(45.5%), and type 3 : short and normal trunk(17.6%) with some significant differences among them. Also, the results of shape classification by index values, they were extracted 4 factors (waist-hip flatness, waist-hip cross section, vertical waist-groin and hip-surface length) by factor analysis and revealed 3 types(type 1: different waist-hip width, thick, long waist, long upper hip, and short hip-surface length(27.8%), type 2 : different waist-hip width, flat, short upper hip, high hip and groin, and average hip-surface length(29.4%), and type 3: small waist-hip width, thick, average upper hip, and short hip-surface length (42.8%)) with significant differences among them by cluster analysis. The results of standard body types by shape-size combination, 19subjects(10.16%) under these values are regarded as standard body types. Significance was not seen in all items in the t-test results between the total group and the standard group. The latter had lower variation coefficients and smaller individual differences than the former. However, in-depth research is required for generalization since this research is limited to a small number of subjects in Ningbo of Zhejiang.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.53-82
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• 2012

The purpose of this paper is to show the clustering trend by using the context-dependent and measure-specific models for 38 Asian ports during 10 years(2001-2009) with 4 inputs and 1 output. The main empirical results of this paper are as follows. First, clustering results by using context-dependent and measure-specific models are same. Second, the most efficient clustering was shown among the Hong Kong, Singapore, Ningbo, Guangzhou, and Kaosiung ports. Third, Port Sultan Qaboos, Jeddah, and Aden ports showed the lowest level clustering. Fourth, ranking order of attractiveness is Guangzhou, Dubai, HongKong, Ningbo, and Shanghai, and the results of progressive scores confirmed that low level ports can increase their efficiency by benchmarking the upper level ports. Fifth, benchmark share showed that Dubai(birth length), and HongKong(port depth, total area, and no. of cranes) have affected the efficiency of the inefficient ports.

• Journal of Korea Port Economic Association
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• v.34 no.2
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• pp.97-114
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• 2018

The East Asian region, an important part of Korea's imports and exports, is expected to grow further driven by the geographical, political, economic, social, and cultural complementarity. With the recent increase in imports and exports, the port trade volume between Korea and East Asian countries is also growing. However, due to various factors, such as economic size, growth rate, port infrastructure level, and geographical location of these countries, the volume of traffic with these ports is fluctuating. Despite much research on the volatility of port trade volume and changes in port network, this study tries to supplement the gap in a more detailed study of ports in Korea and East Asia since these kinds of studies are limited. The purpose of this study is to analyze the trend of distribution routes of export container cargo among ports in Korea and to present policy and practical implications of Korean trading companies, shipping companies, logistics companies, and port authorities. This study analyzes the variability of the trade volume between Korea's major ports and Daedong. Results show that Shanghai, Ningbo, Ho Chi Minh, and Haiphong were the most important factors in terms of size and volume increase. In terms of ports, the Busan port is the port responsible for trades with Yantai, Weihai, Hakata, Kobe, Ho Chi Minh, and Haiphong; Incheon port deals with Lianyungang, Tianjin, Osaka, Kobe, Ho Chi Minh, Haiphong; Gwangyang port trades with Tianjinxingang, Weihai, Yokohama, Mihn and Tanjong, and Ulsan port is strategically important for the Yantai, Lianyungang, Nagoya, Kobe, Ho Chi Minh and Portkelang ports. Therefore, the Korean government, port authorities, and shipping and logistics companies need to strengthen logistic network cooperation with these ports and actively promote investments in them.

• Journal of Korea Port Economic Association
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• v.30 no.4
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• pp.151-168
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• 2014

The purpose of this paper is to show the brief efficiency and clustering measurement way by using the game cross-efficiency model which is newly introduced in this paper for 13 container ports during 3 years(2009, 2010, and 2013) with 3 input variables(depth, total area, and number of crane) and 1 output variable(container TEU). The main empirical results are as follows. First, the average rankings of game cross-efficiency model are Ningbo, Hongkong, Shanghai, Dubai, Singapore, Qingdao, Kaosiung, Busan, Tokyo, Incheon, Nagoya, Manila, Gwangyang ports in order. Second, according to ANOVA analysis, three models show the similar results in terms of the efficiency rankings. Third, in the clustering analysis using dendrogram, group A(Shangahi and Busan), group B(Ningbo and Nagoya), and group C(Incheon and Manila) show the common clustering ports during 3 or 2 years. The policy implication of this paper is that Korean port policy planner should introduce the game cross-efficiency method when measuring the individual port efficiency. Also port authority should consider the merits of the clustering ports for improving the port management and operations.

• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.23-55
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• 2014

The purpose of this paper is to show the clustering trend and to choose the clustering ports for 3 Korean ports(Busan, Incheon and Gwangyang Ports) by using the self organizing maps based on neural network(SOM) and Tier models for 38 Asian ports during 11 years(2001-2011) with 4 input variables(birth length, depth, total area, and number of crane) and 1 output variable(container TEU). The main empirical results of this paper are as follows. First, clustering results by using SOM show that 3 Korean ports[Busan(26.5%), Incheon(13.05%), and Gwangyang(22.95%) each]can increase the efficiency. Second, according to Tier model, Busan(Hongkong, Sanghai, Manila, and Singapore), Incheon(Aden, Ningbo, Dabao, and Bangkog), and Gwangyang(Aden, Ningbo, Bangkog, Hipa, Dubai, and Guangzhou) should be clustered with those ports in parentheses. Third, when both SOM and Tier models are mixed, (1) efficiency improvement of Busan Port is greater than those of Incheon and Gwangyang ports. (2) Incheon port has shown the slow improvement during 2001-2007, but after 2008, improvement speed was high. (3) improvement level of Gwangyang port was high during 2001-2003, but after 2004, improvement level was constantly decreased. The policy implication of this paper is that Korean port policy planner should introduce the SOM, and Tier models with the mixed two models when clustering among the Asian ports for enhancing the efficiency of inputs and outputs.

• Korea Trade Review
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• v.41 no.3
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• pp.27-42
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• 2016

This study is to investigate seaport clustering by using meta-frontier and cross-efficiency models. Data covers the 13 Asian ports during 2009, 2010 and 2013 with 3 inputs(depth, total area, and number of cranes) and 1 output(TEU). Correlations coefficient from cross-efficiency matrix are used for measuring clustering dendrogram. After that, meta-frontier analysis for investigating whether the clustering using cross-efficiency method increases the meta-efficiency. Empirical main results are as follows: First, group efficiencies of Busan, Incheon, and Gwangyang ports are increased. Second, meta and group efficiencies of China ports are greater than those of Korean ports. Third, distortion of technology gap of Gwangyang is lower than that of Busan and Incheon. Fourth, Gwangyang, clustering with Ningbo, Chingtao, Tokyo and Caosung ports in 2009 and with Dubai port in 2013 can increase the efficiency. Fifth, to enhance the efficiency, Busan port should be clustered to group 2 in 2010 and group 1 in 2013, and Incheon port clustered to group 2 in 2010 and 2013. Fifth, it is empirically investigated that Busan, Incheon and Gwangyang ports can increase the efficiency by using Cross-efficiency and Meta-frontier models. Port policy planner should promote the clustering policy for Busan with Hong Kong, Shanghai, and Singapore, Incheon and Gwangyang with Chingtao, Nagoya, Ningbo, Tokyo, and Kaoshung ports.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.237-244
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• 2020

To achieve a wide suction range, the low suction was imposed on compacted silt specimens by the axis translation technique and the high suction was imposed by the vapor equilibrium technique with saturated salt solutions. Firstly, the results of soil water retention tests on compacted silt show that the soil water retention curves in terms of gravimetric water content versus suction relation are independent of the dry density or void ratio in a high suction range. Therefore, triaxial tests on compacted silt with constant water content at high suctions can be considered as that with constant suction. Secondly, the results of triaxial shear tests on unsaturated compacted silt with the initial void ratio of about 0.75 show a strain-hardening behavior with a slightly shear contraction and then strain-softening behavior with an obviously dilation. As the imposed suction increases, the shear strength increases up to a peak value and then decreases when the suction is beyond a special value corresponding to the peak shear strength. The residual strength increases to fair value and those at high suctions are almost independent of imposed suctions. In addition, the contribution of suction to the strength of compacted silt would not diminish even in a high suction range.