• Journal of the Korea Society of Computer and Information
• /
• v.29 no.5
• /
• pp.155-164
• /
• 2024

This study proposes an unsupervised learning-based clustering model to estimate the ESG ratings of domestic public institutions. To achieve this, the optimal number of clusters was determined by comparing spectral clustering and k-means clustering. These results are guaranteed by calculating the Davies-Bouldin Index (DBI), a model performance index. The DBI values were 0.734 for spectral clustering and 1.715 for k-means clustering, indicating lower values showed better performance. Thus, the superiority of spectral clustering was confirmed. Furthermore, T-test and ANOVA were used to reveal statistically significant differences between ESG non-financial data, and correlation coefficients were used to confirm the relationships between ESG indicators. Based on these results, this study suggests the possibility of estimating the ESG performance ranking of each public institution without existing ESG ratings. This is achieved by calculating the optimal number of clusters, and then determining the sum of averages of the ESG data within each cluster. Therefore, the proposed model can be employed to evaluate the ESG ratings of various domestic public institutions, and it is expected to be useful in domestic sustainable management practice and performance management.

• Journal of the Korean Society for Library and Information Science
• /
• v.52 no.1
• /
• pp.313-340
• /
• 2018

The purpose of this study was to design a PCSI model that can be applicable to measurement of library user satisfactions, which can be used in evaluating organizational performance. The National Assembly Library (NAL) was selected as a case to design a PCSI-based model and to test the model by conducting a self-administered survey of 341 internal and external library users. The model was validated to have a satisfactory model fit. Fitting the model, the study confirms that the service qualities of the NAL affect user satisfactions, which in turn affects organizational performances. The PCSI score of the library was 80.4, which can be used as a useful index that can compare the library's performance with other organizations in the similar public domain. Major contributions of this study are two-fold: the PCSI-based model proposed in this study provides a theoretical basis that assesses organizational performance of libraries via user satisfaction; and libraries can utilize the model as a management tool to assess the organizational performance from the user perspective.

• Current Optics and Photonics
• /
• v.7 no.4
• /
• pp.398-407
• /
• 2023

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

• Health Policy and Management
• /
• v.3 no.1
• /
• pp.84-101
• /
• 1993

The current method of rate adjustment is based on the evaluation of the financial performance of hospitals. The method has the disadvantages such as too complicated, expensive process as well as low reliability due to small sample size. This study, therefore, develops a new model for the rate adjustment with the use of the composite index. In addition to that, it examines the validity of the model by comparing the result of the new method with that of the conventional method. The idea of the new model comes from the Medicare Economic Index(MEI) on which physician fees for the Medicare patients are adjusted periodically in the United States. Medical costs are classified into three groups : labor costs, materials and other expenses. Labor costs are subdivided into physicians and other personnels. Materials are subdivided into drugs and others. Other expenses are subdivided into 5 items. Macro economic indices are selected for each cost item in order to reflect the cost inflation during the specific period. Then the composite index which integrate all items according to the ration of each item in the total costs is calculated. The result from the application of empirical data to the new model is very similar to that of the current method. Furthermore, this method is very simple and also to easy to get social concensus. This model can be replaced the current method based on the analysis of the financial performance for the adjustment of medical fees.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.3_4
• /
• pp.412-421
• /
• 2002

The main purpose of this study was to examine whether there exist physical attractiveness stereotype, ‘what is beautiful is good’on the evaluation of stimulus person’s task performance in present Korea. This study also examine the effects of the appropriateness of the stimulus person’s clothing and subjects’sexes on the task performance evaluation. The index of the physical attractiveness of this study was the facial attractiveness judged by 30 female university students. The appropriateness of clothing was manipulated by 4 types of clothing perceived appropriate for two assumed situations by female university students. Three female faces having high, medium, and low attractiveness were simulated with the same body dressed four types of clothing using CAD system, and a total of 12 stimulus persons were created. A total of 524 male and female(262 of male, 262 of female) university students from 3 universities in Kwangju, Korea were participated as subjects in this study. The design for the experiment was a $3\;{\times}\;4\;{\times}\;2$ randomaized factorial, with three levels of facial attractiveness (high, medium, low), and four types attire(formal-masculine, formal-feminine, casual-masculine, casual-feminine), two kinds of context (job interview, dating) in which perceptions were occurred. The data were analysed using MANOVA, Duncan test and F-test. The results were as fellows: 1. The stimulus person’s facial attractiveness exerted significant positive effects on the evaluation of task performance in both of two assumed situations (p<.001, respectively). 2. The appropriateness of stimulus person’s clothing did not influence on the task evaluation in both of two assumed situations. 3. The gender of subjects did not influenced the task performance evaluation in both of two assumed situations.

• Korean Journal of Radiology
• /
• v.22 no.10
• /
• pp.1697-1707
• /
• 2021

The recent introduction of various high-dimensional modeling methods, such as radiomics and deep learning, has created a much greater diversity in modeling approaches for survival prediction (or, more generally, time-to-event prediction). The newness of the recent modeling approaches and unfamiliarity with the model outputs may confuse some researchers and practitioners about the evaluation of the performance of such models. Methodological literacy to critically appraise the performance evaluation of the models and, ideally, the ability to conduct such an evaluation would be needed for those who want to develop models or apply them in practice. This article intends to provide intuitive, conceptual, and practical explanations of the statistical methods for evaluating the performance of survival prediction models with minimal usage of mathematical descriptions. It covers from conventional to deep learning methods, and emphasis has been placed on recent modeling approaches. This review article includes straightforward explanations of C indices (Harrell's C index, etc.), time-dependent receiver operating characteristic curve analysis, calibration plot, other methods for evaluating the calibration performance, and Brier score.

• The Pure and Applied Mathematics
• /
• v.3 no.2
• /
• pp.141-154
• /
• 1996

A data-driven index of dimensionality for an educational or psychological test - DETECT, short for Dimensionality Evaluation To Enumerate Contributing Traits, is proposed in this paper. It is based on estimated conditional covariances of item pairs, given score on remaining test items. Its purpose is to detect whatever multidimensionality structure exists, especially in the case of approximate simple structure. It does so by assigning items to relatively dimensionally homogeneous clusters via attempted maximization of the DETECT over all possible item cluster partitions. The performance of DETECT is studied through real and simulated data analyses.

• Journal of KIISE:Databases
• /
• v.31 no.6
• /
• pp.675-683
• /
• 2004

In main-memory resident index structures, secondary cache misses considerably have an effect on the performance of index structures. Recently, several main-memory resident index structures that consider cache have been proposed to reduce the impact of secondary cache misses. However they still suffer from full secondary cache misses whenever visiting each level of a index tree. In this paper, we propose a new index structure that eliminates cache misses even when visiting each level of index tree. The proposed index structure prefetches the grandchildren of a current node. The basic structure of the proposed index structure is from CSB+-tree that uses the concepts of the node group to increase fan-out. However the insert algorithm of the proposed index structure reduces the cost of a split significantly. Also, we show the superiority of our algorithm through various performance evaluation.

• Journal of Internet Computing and Services
• /
• v.4 no.6
• /
• pp.75-86
• /
• 2003

In main-memory resident index structures, secondary cache misses considerably have an effect on the performance of index structures. Recently, several main-memory resident index structures that consider cache have been proposed to reduce the impact of secondary cache misses. However they still suffer from full secondary cache misses whenever visiting each level of a index tree, In this paper, we propose a new index structure that eliminates cache misses even when visiting each level of index tree. The proposed index structure prefetches the grandchildren of a current node. The basic structure of the proposed index structure is from CSB+-tree that uses the concepts of the node group to increase fan-out. However the insert algorithm of the proposed index structure reduces the cost of a split significantly, Also, we show the superiority of our algorithm through various performance evaluation.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.6
• /
• pp.13-21
• /
• 2010

Road Traffic Authority and National Police Agency is currently managing the "development of an integrated metropolitan traffic information infrastructure" that installs of facilities for a traffic information infrastructures, such as Local Traffic Information Center, UTIS(Urban Traffic Information System), CCTV, VMS and etc. CTIC was established in 2005 to act as an traffic information hub and to provide integrated UTIS traffic information without regional barriers. This study was carried out to seek for solution to improve quality of UTIS traffic information service for the Central Traffic Information Center(CTIC). In this study, the Evaluation index for UTIS traffic information service was developed and the implementation plan was established by using requirement analysis method, case study and AHP(Analytic Hierarchy Process) technique. The Evaluation index consist of 5 fields and 20 index, it make possible evaluation of direct/indirect effect for UTIS traffic information service. In conclusion, It is expected that quality of UTIS traffic information service will be improved by using developed evaluation index and also can be applied for performance evaluation of other traffic information systems.