• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.2
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• pp.116-120
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• 2008

Clustering is a method for unsupervised learning. General clustering tools have been depended on statistical methods and machine learning algorithms. One of the popular clustering algorithms based on machine learning is the self organizing map(SOM). SOM is a neural networks model for clustering. SOM and extended SOM have been used in diverse classification and clustering fields such as data mining. But, SOM has had a problem determining optimal number of clusters. In this paper, we propose an improvement of SOM using gap statistic and probability distribution. The gap statistic was introduced to estimate the number of clusters in a dataset. We use gap statistic for settling the problem of SOM. Also, in our research, weights of feature nodes are updated by probability distribution. After complete updating according to prior and posterior distributions, the weights of SOM have probability distributions for optima clustering. To verify improved performance of our work, we make experiments compared with other learning algorithms using simulation data sets.

• The Korean Journal of Applied Statistics
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• v.32 no.3
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• pp.331-348
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• 2019

Understanding the tumor heterogeneity due to differences in the growth pattern of metastatic tumors and rate of change is important for understanding the sensitivity of tumor cells to drugs and finding appropriate therapies. It is often possible to test for differences in population means using t-test or ANOVA when the group of N samples is distinct. However, these statistical methods can not be used unless the groups are distinguished as the data covered in this paper. Statistical methods have been studied to test heterogeneity between samples. The minimum combination t-test method is one of them. In this paper, we propose a maximum combinatorial t-test method that takes into account combinations that bisect data at different ratios. Also we propose a method based on the idea that examining the heterogeneity of a sample is equivalent to testing whether the number of optimal clusters is one in the cluster analysis. We verified that the proposed methods, maximum combination t-test method and gap statistic, have better type-I error and power than the previously proposed method based on simulation study and obtained the results through real data analysis.

• Journal of Korea Port Economic Association
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• v.28 no.4
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• pp.231-255
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• 2012

This study examined the communication and conflict between ship prganization and ship management team. Those are measured and analyzed about both groups, and then the relationships would be investigated objectively and synthetically. Especially, this relationships are enlightened by measuring the level and gap of the communication and group conflict between ship organization and ship management team. The effect of that conflict is analyzed on the organization commitment and job satisfaction of ship organizations. As a result, this study demonstrates the communications have a negative influence on group conflict with statistic significance, also the conflicts effect negatively on the organization commitment and job satisfaction. In the analysis of gaps about the communication and conflict between groups, the level of group conflict is lowest in the group whose gap of communication is small and both communications are activated, and the organization commitment and job satisfaction are highest in the group whose gap of group conflicts is small and both level of the conflicts are low. To conclude, the ship organization and ship management teams in the shipping company have to lessen their conflict each other and heighten the organization commitment and job satisfaction through their smooth communication.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.613-618
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• 2005

When a large peripheral nerve defect occurs, an autologous nerve graft is the most ideal method of recinstruction. But an autologous nerve graft has many limitations due to donor site morbidities. Many previous focused on finding the ideal nerve conduit. Among them, $Gore-Tex^{(R)}$ has several advantages over other conduits. It can be manipulated to a suitable size, does not collapse easily, and it is a semi- permeable material that contain pores. A round shaped nerve can be newly formed because of its smooth inner surface. The purpose of this study was to evaluate the availability of $Gore-Tex^{(R)}$ tube as a nerve conduit at the peripheral nerve defect in the rat sciatic nerve. The 10 mm nerve gap was made in each group. A $Gore-Tex^{(R)}$ tube filled with skeletal muscle was inserted and autologous nerve graft was harvested, respectively. In the experimental group, we placed a 0.5 mm thickness, $30{\mu}m$ pored, 1.8 mm in diameter and 14 mm length tube with skeletal muscle inserted inside. In the control group, the nerve gap was inserted with a rat sciatic nerve. We estimated the results electrophysiologically and histologically to 16 weeks postoperatively. Results in the nerve conduction velocity, total myelinated axon count, myelin sheath thickness and mean nerve fiber diameter, the experimental group was substantially lower than that of the control group, but the statistic difference was not significant (p<0.05). The morphology was very similar in both groups, microscopically. From the above results, We conclude that $Gore-Tex^{(R)}$ qualifies as an ideal nerve conduit. It is suggested that $Gore-Tex^{(R)}$ tube filled with skeletal muscle may, substitute for an autologous nerve graft.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.85-93
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• 1980

This study was undertaken in order to observe the prevalence of congenital dental anomalies especially that of oligodontia and supernumerary teeth in 1024 children at age from 4 to 14 years, through history taking, oral examinations, roentgenographic observations of subjects, and statistic analysis was made. The following results were obtained: 1. The prevalence of oligodontia in 1024 children was $6.45{\pm}.8$ percent with a total of 122 teeth absent in sixty-six subjects, excluding 3rd molars, and most of children (86.4%) who have congenitally missing teeth showed abscence of one or two teeth individually. 2. The teeth most frequently absent were the mandibular second premolar, maxillary second premolar, maxillary lateral incisor, mandibular central incisor, and mandibular lateral incisor in order. 3. There was no statistically significant difference found in tooth abscence in the following comparisons; .Male vs Female .Bilateral vs Unilateral .Maxilla vs Mandible .Right vs Left 4. The prevalence of supernumerary teeth in 1024 children was $4.79{\pm}.67$ percent with a total of 59 supernumerary teeth in forty-nine subjects, all of children who have supernumerary teeth showed one or two supernumerary teeth individually. 5. Statistically significant difference was found in supernumerary teeth in the comparison of male vs female, and they were more frequent in male.

• The Korean Journal of Health Service Management
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• v.12 no.1
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• pp.13-22
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• 2018

Objectives : This study examines the voluntary participation of the members of an organization who maintain cordial and friendly relationships with their colleagues, so that the human resources department within a hospital can be used efficiently. Methods : A total of 600 copies of the questionnaire were distributed, and 524 copies were returned (88%). Of these, 518 copies were used to verify statistic results using IBM SPSS and AMOS Ver. 22.0, including factor analysis, path analysis, mediating effects, and moderating effects. Results : The effect of organizational trust on organizational citizenship behavior has shown that OCBI (Interpersonal) is highly affected at large hospitals. However, the effect of organizational trust on OCBO (Organizational) is highly affected at small hospitals. Conclusions : The results of a gap analysis indicated that among the different aspects of organizational justice, distributive justice and interactional justice have a positive effect on organizational trust in small hospitals. The results also revealed that organizational trust and organizational citizenship behavior in small hospitals are more strongly affected than they are in large hospitals. As a result, job efficiency is improved in smaller hospitals.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.1033-1039
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• 2020

Vietnam is conducting an export-led growth model and labour-intensive industries contributing majorly to the total export value. In the context of Industry 4.0, the labour-based industries are significantly affected; hence, enhancing productivity is the key measure to maintain these industries. The garment industry contributes significantly to the total export value of Vietnam. Based on meta-frontier framework, the approach of data envelopment analysis is used to measure technical efficiency of Vietnamese garment firms and the global Malmquist TFP index is utilised to identify productivity change and its components including efficiency, technology and technical gaps between different groups of firms. The data of Vietnamese garment firms from 2013 to 2018 collected from the Vietnam General Statistic Office is used in this study. The results show that: (i) The total factor productivity of Vietnamese garment firms growth, technical progress is the main contributor; (ii) The private garment sector is the leading group; (iii) There is a large technological gap among Vietnamese garment sectors. The private and FDI garment firms have experienced a growth in all components of total factor productivity change. Meanwhile, technological progress change is the main reason to constrain the productivity growth of state-owned garment firms.

• Journal of Distribution Science
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• v.20 no.9
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• pp.47-59
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• 2022

Purpose: This study aims to analyze a triangulation model: 1) the effect of entrepreneurship education (EE) on entrepreneurship knowledge (EK) and entrepreneurship mindset (EM) and 2) the effect of EK on EM. Entrepreneurship education is a medium and pedagogical tool to cultivate EK and EM with the purpose enhancing of students who will be interested in entrepreneurial activities. Knowledge of adequate entrepreneurship is a stimulus strategic tool to develop the entrepreneurial mindset of students. Research design, data, and methodology: There were 278 respondents from Business and Non-Business both Indonesian and Malaysian students. The research design was quantitative and evaluated three hypotheses by PLS-SEM using WarpPLS v.7 software. Statistic descriptive for respondent used SPSS IBM v.26. Results: The results showed that the three hypotheses had supported with a significant level of p-value < 0.001. It's meant EE enhanced both EK and EM. Furthermore, increasing EM was not only by EE, but also EM could be increased through EK. Conclusions: The novelty of this research contributes to filling the knowledge gap in the development of pedagogy in the pursuit of entrepreneurship using a triangulation model of the relationship among EE, EK, and EM.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.5
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• pp.611-621
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• 2005

State of problem: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. Purpose: This study was to evaluate the at of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). Material and Method: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesio-distal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of $\times100$. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. Results and Conclusion: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia$(81.9{\mu}m)$ and metal $(81.3{\mu}m)$ framework and internal marginal gaps of zirconia $(44.6{\mu}m)$ were smaller than those of metal framework $(58.6{\mu}m)$. 2. Internal axial gaps of zirconia framework$(96.7{\mu}m)$ were larger than those of metal frame-work$(78.1{\mu}m)$ significantly and adversely, internal occlusal gaps of zirconia frame-work$(89.4{\mu}m)$ were smaller than those of metal framework $(104.9{\mu}m)$ significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.6
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• pp.545-559
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• 2002

There has been increasing use of IPS Empress $2^{(R)}$ owing to easy fabrication method, high esthetics similar to natural teeth, good marginal accuracy, and sufficient fracture strength. However, in clinical application, although a luting agent and the tooth cementation bonding procedure influence the marginal accuracy and fracture strength restoration, there has been a controversy in the selection of proper luting agent. This study was to measure the marginal fidelites and fracture strength of IPS Empress crowns according to three cement types, Protec $cem^{(R)}$, Variolink $II^{(R)}$ and Panavia $21^{(R)}$. After construction of 12 experimental dies for each group, IPS Empress $2^{(R)}$ crowns were fabricated and luted the metal master die prepartion of the maxillary right premolar. Marginal gaps before cementation and after cementation were measured. Buccal incline on the functional cusp of specimens were loaded until the catastrophic failure and fracture strength was measured. The results of this study were as follows: 1. The range of gap was $34.04{\pm}4.84{\mu}m$ before cementation and $37.88{\pm}5.00{\mu}m$ after cementation, which showed significant difference by paired t-test (p<0.05). The difference in the results from marginal accuracy according to measuring point proved to be not statistically significant by two-way ANOVA test (p>0.05). 2. The difference in the results from marginal accuracy according to three cement types Proved that The Variolink $II^{(R)}$ cement group had the least gap, $35.43{\pm}5.03{\mu}m$, and showed superior marginal accuracy while there existed statistic significance in Protec $cem^{(R)}$ cement group, $39.06{\pm}4.41{\mu}m$ or Panavia $21^{(R)}$ cement group, $39.16{\pm}4.39{\mu}m$ by two-way ANOVA test & multiple range test (p<0.05). 3. The difference in the results from fractures strength testing according to three cement type groups proved to be statistically significant (p<0.05). The Variolink $II^{(R)}$ cement group shows highest fracture strength of $1257.33{\pm}226.77N$, Panavia $21^{(R)}$ cement group has $1098.08{\pm}138.45N$, and Protec $cem^{(R)}$ cement group represents the lowest fracture strength of $926.75{\pm}115.75N$. 4. Three different cement groups of different components showed acceptable marginal fidelity and fracture strength. It is concluded that IPS Empress $2^{(R)}$ crowns luted using Variolink $II^{(R)}$ cement group had stronger fracture strength and smaller marginal gap than the other cement groups. Although Variolink $II^{(R)}$ resin cement seemed acceptable to clinical applications in IPS Empress $2^{(R)}$ system, the IPS Empress $2^{(R)}$ system still requires long-term research due to the lack of data in clinical applications.