• Title/Summary/Keyword: Missing Values

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Development of A Performance Model of the Foodservice Industry

  • Seo, Kyung Hwa;Jeon, Yu Jung Jennifer;Lee, Soo Bum
    • Culinary science and hospitality research
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    • v.22 no.6
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    • pp.132-144
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    • 2016
  • This study reviewed previous researches about the competence selection of foodservice firms, and shows firm's performance model through the results. The study classified factors according to core competence, differentiation strategy, and management performance. Out of 400 survey responses from by the firm's executive and employees who had worked for over three years at the headquarters (sales, financial, marketing/plan, R & D, etc.), a total of 302 questionnaires were used for the final analysis due to missing values and biased responses (response rate: 75.5%). As the results of analyzing final research model of this study, it appeared that ${\chi}^2(df=170)=384.88$, ${\chi}^2/df=2.26$, GFI=0.90, NFI=0.92, CFI=0.95, RMSEA=0.07. The results indicated that the CEO leadership, organizational culture, and human resource competencies are a driving force in all aspects of competitive advantage differentiation strategies. In addition, the R & D innovation, service, and marketing differentiation strategies are positively related to performance. The results validate the fact that foodservice firms could reinforce strategic decisions through a variety core competencies and achieve continuous performance through competitive strategies.

The Effects of Authentic Leadership on Service-Oriented Organizational Citizenship Behaviors: The Role of Goal Commitment as a Mediator - A Case of Five Star Deluxe Hotel Employees -

  • Kwon, Yong-Joo;Kim, Ji-Eun
    • Culinary science and hospitality research
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    • v.22 no.6
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    • pp.33-51
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    • 2016
  • The hotel industry needs to make the competitive advantage difficult to be imitated in order to remain sustainable in competitive business circumstances. Front-line employees' service-oriented citizenship behaviors(OCBs) can be such a strength from the perspective of organizational system. With an aim of investigating the antecedents of the hotel front-line employees' service-oriented OCBs, this study proposed a theoretical framework linking authentic leadership to service-oriented OCBs with goal commitment as a mediator. A total of 260 cases without missing values have been used for the final analysis and structural equation modeling (SEM) is employed using the SPSS and AMOS 7. It was first found that self-awareness and relational transparency of authentic leadership made a significant impact on their goal commitment while balanced processing and moral perspective failed to influence them. Second. goal commitment influenced all sub-factors of service-oriented OCBs. Third, moral perspective and relational transparency of authentic leadership significantly influenced service-oriented OCBs while self-awareness and relational transparency failed to make it. Finally, goal commitment significantly makes an intervening effect for the relationship between self-awareness & service-oriented OCBs and relational transparency & service-oriented OCBs but failed to intervene the other relationships. The results provide theoretical and practical implications regarding directions of leadership styles and HR management in the hotel industry and suggestions for the further extended studies.

Statistical Method of Ranking Candidate Genes for the Biomarker

  • Kim, Byung-Soo;Kim, In-Young;Lee, Sun-Ho;Rha, Sun-Young
    • Communications for Statistical Applications and Methods
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    • v.14 no.1
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    • pp.169-182
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    • 2007
  • Receive operating characteristic (ROC) approach can be employed to rank candidate genes from a microarray experiment, in particular, for the biomarker development with the purpose of population screening of a cancer. In the cancer microarray experiment based on n patients the researcher often wants to compare the tumor tissue with the normal tissue within the same individual using a common reference RNA. Ideally, this experiment produces n pairs of microarray data. However, it is often the case that there are missing values either in the normal or tumor tissue data. Practically, we have $n_1$ pairs of complete observations, $n_2$ "normal only" and $n_3$ "tumor only" data for the microarray. We refer to this data set as a mixed data set. We develop a ROC approach on the mixed data set to rank candidate genes for the biomarker development for the colorectal cancer screening. It turns out that the correlation between two ranks in terms of ROC and t statistics based on the top 50 genes of ROC rank is less than 0.6. This result indicates that employing a right approach of ranking candidate genes for the biomarker development is important for the allocation of resources.

Modified BLS Weight Adjustment (수정된 BLS 가중치보정법)

  • Park, Jung-Joon;Cho, Ki-Jong;Lee, Sang-Eun;Shin, Key-Il
    • Communications for Statistical Applications and Methods
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    • v.18 no.3
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    • pp.367-376
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    • 2011
  • BLS weight adjustment is a widely used method for business surveys with non-responses and outliers. Recent surveys show that the non-response weight adjustment of the BLS method is the same as the ratio imputation method. In this paper, we suggested a modified BLS weight adjustment method by imputing missing values instead of using weight adjustment for non-response. Monthly labor survey data is used for a small Monte-Carlo simulation and we conclude that the suggested method is superior to the original BLS weight adjustment method.

Effects of Normalization and Aggregation Methods on the Volatility of Rankings and Rank Reversals (정규화 및 통합 방법이 순위의 변동성과 순위 역전에 미치는 영향)

  • Park, Youngsun
    • Journal of Korean Society for Quality Management
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    • v.41 no.4
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    • pp.709-724
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    • 2013
  • Purpose: The purpose of this study is to examine five evaluation models constructed by different normalization and aggregation methods in terms of the volatility of rankings and rank reversals. We also explore how the volatility of rankings of the five models changes and how often the rank reversals occur when the outliers are removed. Methods: We used data published in the Complete University Guide 2014. Two universities with missing values were excluded from the data. The university rankings were derived by using the five models, and then each model's volatility of rankings was measured. The box-plot was used to detect outliers. Results: Model 1 has the lowest volatility among the five models whether or not the outliers are included. Model 5 has the lowest number of rank reversals. Model 3, which has been used by many institutions, appears to be in the middle among the five in terms of the volatility and the rank reversals. Conclusion: The university rankings vary from one evaluation model to another depending on what normalization and aggregation methods are used. No single model exhibits clear superiority over others in both the volatility and the rank reversal. The findings of this study are expected to provide a stepping stone toward a superior model which is both reliable and robust.

Process Conditions Optimizing the Yield of Power Semiconductors (전력반도체의 수율향상을 위한 최적 공정조건 결정에 관한 연구)

  • Koh, Kwan Ju;Kim, Na Yeon;Kim, Yong Soo
    • Journal of Korean Society for Quality Management
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    • v.47 no.4
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    • pp.725-737
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    • 2019
  • Purpose: We used a data analysis method to improve semiconductor manufacturing yield. We defined and optimized important factors and applied our findings to a real-world process. The semiconductor industry is very cost-competitive; our findings are useful. Methods: We collected data on 15 independent variables and one dependent variable (yield); we removed outliers and missing values. Using SPSS Modeler ver. 18.0, we analyzed the data both continuously and discretely and identified common factors. Results: We optimized two independent variables in terms of process conditions; yield improved. We used DS Leak software to model netting and Contact CD software to model meshes. DS Leak shows smaller the better characterisrics and Contact CD shows normal the best characteristics Conclusion: Various efforts have been made to improve semiconductor manufacturing yields, and many studies have created models or analyzed various characteristics. We not only defined important factors but also showed how to control processing to improve semiconductor yield.

The Development of Meta-Information System for Microbial Genome Resources (미생물 게놈자원을 위한 메타정보 시스템의 개발)

  • Chung, Won-Hyong;Yu, Jae-Woo;Sohn, Tae-Kwon;Park, Yong-Ha;Kim, Hong-Ik
    • Proceedings of the Korean Society for Bioinformatics Conference
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    • 2003.10a
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    • pp.245-250
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    • 2003
  • There are currently about 6000 bacterial species with validly published names, but scientists assume that these may be less than 1% of bacterial species present on the earth. Microbial resource is one of the most important bioresources in bioinderstry and provides us with high economic values. To find missing ones, the studies of metagenome, metabolome, and proteome about microbes have started recently in developed countries. We construct the information system that integrates information on microbial genome resources and manages the information to support efficient research of microbial genome application, and name this system 'Bio-Meta Information System (Bio-MIS)'. Bio-MIS consists of integrated microbial genome resources database, microbial genome resources input system, integrated microbial genome resources search engine, microbial resources on-line distribution system, portal service and management via internet. In the future, we will include public database connection and implement useful bioinformatics software for analyzing microbial genome resources. The web-site is accessible at http://biomis.probionic.com

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Evaluation of DNA Microarray Approach for Identifying Strain-Specific Genes

  • Hwang, Keum-Ok;Cho, Jae-Chang
    • Journal of Microbiology and Biotechnology
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    • v.16 no.11
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    • pp.1773-1777
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    • 2006
  • We evaluated the usefulness of DNA microarray as a comparative genomics tool, and tested the validity of the cutoff values for defining absent genes in test genomes. Three genome-sequenced E. coli strains (K-12, EDL933, and CFT073) were subjected to comparative genomic hybridization with DNA microarrays covering almost all ORFs of the reference strain K-12, and the microarray results were compared with the results obtained from in silico analyses of genome sequences. For defining the K-12 ORFs absent in test genomes (reference strain-specific ORFs), we applied and evaluated the cutoff level of -1. The average sequence similarity between ORFs, to which corresponding spots showed a log-ratio of>-1, was $96.9{\pm}4.8$. The numbers of spots showing a log-ratio of <-1 (P<0.05, t-test) were 90 (2.5%) and 417 (10.6%) for the EDL933 genome and the CFT073 genome, respectively. Frequency of false negatives (FN) was ca. 0.2, and the cutoff level of -1.3 was required to achieve the FN of 0.1. The average sequence similarity of the false negative ORFs was $77.8{\pm}14.8$, indicating that the majority of the false negatives were caused by highly divergent genes. We concluded that the microarray is useful for identifying missing or divergent ORFs in closely related prokaryotic genomes.

Development of a Robotic Manipulator for a Cucumber Harvester (오이 수확용 로봇 매니퓰레이터 개발)

  • 이대원;이원희;김현태;민병로;성시흥
    • Journal of Biosystems Engineering
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    • v.26 no.6
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    • pp.535-544
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    • 2001
  • This study developed a manipulator for robotic harvester to harvest cucumber. The manipulator was designed and built fur transferring an end-effecter from a fixed point to a specified cucumber. Its development involved the integration of a manipulating system with a PC compatible, DC motors, geared boxes, timing belts, and a motor controller board. Software, written in Quick basic. combined the functions of motor control with various circumstances. In order to move smoothly and rapidly the manipulator, it's shoulder link and elbow link were minimized by using rotational inertial moment without a motor and a geared box. After 30 replications of exercising the manipulator, it was concluded that the precision values of the X, Y and Z axes were less than 0.5mm, 7.25mm and 0.35mm, respectively. The precision data indicated the manipulator was not missing any steps fur the harvester to reach a target cucumber.

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An Efficient 3-D Deinterlacing Algorithm by Detecting Accurate Motions Using Adaptive-Thresholded Values (적응적인 임계값을 적용한 정확한 움직임 검출과 이를 이용한 효율적인 3-D 디인터레이싱 알고리즘)

  • Cho, Dae-Rim;Song, Jin-Mo;Lee, Dong-Ho
    • Journal of Korea Multimedia Society
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    • v.13 no.11
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    • pp.1610-1620
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    • 2010
  • This paper proposes a motion-adaptive 3-D deinterlacing algorithm based on an adaptive-thresholded motion detection and an interpolation method using binary patterns to compensate motion missing and false motion errors. For efficient motion detection, we adaptively decided a threshold value according to the complexity of image. Many edge-based interpolation algorithms have been proposed to improve the subjective quality. Recently, to efficiently interpolate low angle edge and line, a method using predefined binary patterns has been proposed. In this paper, we propose an improved method by modifying the binary patterns. Simulation results have shown that the proposed method provides better performance than the existing methods.