• Journal of the Institute of Convergence Signal Processing
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• v.2 no.4
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• pp.53-58
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• 2001

In this paper to develop objective speech quality measure for CDMA telephone network environments, recent developed measures are investigated first. But those measures show low performances in CDMA telephone networks. To solve this problem, new objective speech quality measure adopting noise masking threshold is proposed and studied. To acquire better performance, scaled noise masking threshold calculation for speech signals is employed instead of conventional tone signals. To verify effectiveness of proposed method performance comparison experiments are carried out for CDMA telephone network speech databases, for the results proposed methods show improved performances compared to existing meaures.

• Journal of Korean Society for Quality Management
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• v.46 no.1
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• pp.153-168
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• 2018

Purpose: The balanced scorecard (BSC) has been adopted to evaluate factors affecting performances in organizational dealer marketing in Chinese cosmetics market. Four performance measures in BSC: learning & growth, internal business processes, customer performance, and financial performance are employed in our empirical study. Methods: We conducted surveys of dealers in a Chinese cosmetics company and used total 463 samples for analysis. Confirmatory factor analysis and structural equation model analysis were employed using AMOS 20.0. Results: This study found that internal business process had a positive relation with customer performance and learning and growth. Also, customer performance and learning & growth positively affected financial performances. Conclusion: This study has some academic and practical contributions in that the revised BSC model reflects the special aspects of Chinese cosmetics market and it can be used as a guide for companies in the Chinese cosmetics market to understand which factors are affecting performances.

• Journal of the Korea Society for Simulation
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• v.3 no.2
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• pp.27-36
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• 1994

In many real-world simulation studies the several measures of performance are of interest simultaneously. There exist very limited number of studies that explain and suggest the methods or procedures of inferencing the system performances at the same time. This study presents a procedure for determining the number of simulation observations required to achieve the prespecified confidence level for several measures of system performance. Mean values are selected as the measures, for instance, expected ordering cost, expected holding cost, and expected shortage cost for a given period of time in the study of inventory problems. Basically, the batch means approach is applied and extended to develop an algorithm to carry out the procedure handling more than single parameter. The efficacy of the presented method is assessed through the experiments. The empirical results based on some stochastic systems such as queues and inventory problems show that the suggested method produces as excellent result in terms of the precision of estimated means and the number of observations required.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.225-233
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• 2012

The research discusses interrelationship of structural and reliability importance measures which used in the probabilistic safety assessment. The most frequently used component importance measures, such as Birnbaum's Importance (BI), Risk Reduction (RR), Risk Reduction Worth (RRW), RA (Risk Achievement), Risk Achievement Worth (RAW), Fussel Vesely (FV) and Critically Importance (CI) can be derived from two structure importance measures that are developed based on the size and the number of Minimal Path Set (MPS) and Minimal Cut Set (MCS). In order to show an effectiveness of importance measures which is developed in this paper, the three representative functional structures, such as series-parallel, k out of n and bridge are used to compare with Birnbaum's Importance measure. In addition, the study presents the implementation examples of Total Productive Maintenance (TPM) metrics and alternating renewal process models with exponential distribution to calculate the availability and unavailability of component facility for improving system performances. System state structure functions in terms of component states can be converted into the system availability (unavailability) functions by substituting the component reliabilities (unavailabilities) for the component states. The applicable examples are presented in order to help the understanding of practitioners.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.11
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• pp.1369-1380
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• 2005

This study suggests a strategy of providing apparel product information from the wearers' perspective on Internet shopping malls, as a way of compensating for the lack of opportunities to try on the actual product. On an actual Internet shopping mall that sells apparel product, the 'trial-experience information' (the experiential information provided by the fit models who tried on the products) was provided for 83 different items from four women's wear brands. The traffic and sales performances (number of visitors, page view, gross sales of goods, conversion rate, and the numbers of customer transactions) of the apparel product websites that contain trial-experience information were compared to the performances of the brand's websites before this information was implemented. The changes in percent contribution of these brands in women's wear category were also noted. The specific results are as follows: First, all the four performance measures as well as the percent contribution of the experiment products in women's wear category increased noticeably throughout the experiment period (11 to $103\%$). Second, when the percent contribution of these brands in women's wear category in terms of traffic and sales performances were compared to the previous year, these measures increased between $497\%\;and\;2851\%$. Third, the amount of customer transactions also increased after the trial-information was provided, yet to a relatively smaller extent $(29.04\%\;to\;55.25\%)$. The findings showed that trial-experience information provided on the Internet shopping malls may reduce customers' risk perception and lead to increased sales of apparel product and improve the site use ratio.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.629-635
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• 2012

This paper presents a performance analysis of the GPS(Global Positioning System) receiver on board in LEO satellites, based on the comparison of its in-orbit performances and corresponding ground test results. An extensive ground tests on the subject GPS receiver has been performed in diverse conditions under the right frame of ground test environments and the analysis of in-orbit performances has also been performed with the huge amount of accumulated GPS data which has been in operation for 6 years since its launch on 2006. For this analysis, we chose three sets of in-orbit data; the data during the early mission period, the data at the 3-year mission completion time, and the most recent in-orbit data. As the performance measures, we selected the position and time synchronization accuracy, and the comparative analysis shows the concurrency between the in-orbit performances and the ground test results with in these performance measures, verifying the validity of the ground test. It is expected that the test configuration and analysis method presented in this paper can be applied to developing and verifying the future Koreanized satellite GPS receivers.

• International Commerce and Information Review
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• v.9 no.2
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• pp.65-86
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• 2007

This paper reviews the properties and application methods of widely used types of risk measures, identifies the rationale and business-side effects of hedging, derives the theoretical formula of optimal hedging ratio, and analyzes the various functional aspects of VaR(Value-at-risk) as a risk measure and a hedging tool. Especially this paper focuses on the characteristics of VaR compared with other risk measures in terms of their own principal determinants and identifies its stronger aspects in the dimension of hedging strategy tools. As well, this paper provides the detailed processes deriving the optimal hedge ratios based on the distributional parameters and risk factors. In addition, this paper presents the detailed and substantial processes of estimating the minimum variance hedge ratio and minimum-VaR hedge ratio using the actual data and shows that the minimum variance hedge ratio proves helpful for many cases although it is not appropriate for the non-linear portfolio including the option contracts. We demonstrate the trade-off relationship between the minimum variance hedge strategy and the minimum-VaR hedge strategy in their hedging costs and performances through calculation of the respective VaRs and variances of unhedged and hedged portfolios and the optimal hedge ratio and hedging effectiveness values for the given long position in US Dollar with the short position in Euro.

• Korean Journal of Human Ecology
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• v.20 no.4
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• pp.871-884
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• 2011

This study was conducted to analyze job importance, performance level, and job satisfaction of school and office foodservice dietitians. Self-administered questionnaires were collected from 181 dietitians in the Chungnam area. Statistical data analysis was completed using SPSS v. 14.0. School dietitians were 55% and office dietitians were 45%. Of both, age of 20s and 30s scored 85%; the age of 30s of schools dietians scored 70% while those in office dietians 20s scored 79%. More than 84% of school and office dietitians were university graduates. Total average of job importance of school dietitians was 4.24 and job performance was 3.97 while that of office dietitians was 4.15 and job performances was 3.69. A duty that had a big difference in job importance and performances as a dietitian was 'education of nutrition' (p<.001) and 'self-improvement' (p<.001). According to the meal service except, importance and performances of duties showed a significantly high level (p<.001) for office dietitians, but most measures of job importance and performances showed a high level at school. Therefore, in order to improve job performances and satisfaction for school dietitians, it is necessary to develop systematic and professional education programs for qualification improvement and to grow pride and improve treatment as a nutrition teacher through expansion of appointment. Meanwhile, for office dietitians, it is required to strengthen duty education of 'human resource management' and 'meal service management' through education and supplementary training in companies, on which personal characteristics are reflected.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.438-441
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• 2004

This paper presents the results of the experimental study on the performances of reinforced concrete beams rehabilitated by external unbonded high tension steel-bar. Design variables for the experiment in this study includes the position of anchorage zone of the high tension steel bar, the anchorage length of the reinforcing steel bar and the types of the shear strengthening measures. 5 specimens were tested with one point monotonically increased loads and structural performances such as strength capacities, ductility capacities and failure modes were analysed. It is found that the structural performance of the rehabilitated beams are strongly depended on the location of anchorage zone of the high tension steel-bars. In the case that anchorage zone is located near the critical shear zone, it is observed that the rehabilitated beam is failed in brittle failure mode and the additional shear strengthening is necessitated. But if anchorage zone is properly located or additional shear strengthening device is provided properly, it is also observed that the strength capacity of the rehabilitated beams could be increased more than $200\%$ by the proposed method.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.79-96
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• 2008

One of the roles of the Semantic Web services is to execute dynamic intra-organizational services including the integration and interoperation of business processes. Since different organizations design their processes differently, the retrieval of similar semantic business processes is necessary in order to support inter-organizational collaborations. Most approaches for finding services that have certain features and support certain business processes have relied on some type of logical reasoning and exact matching. This paper presents our approach of using imprecise matching for expanding results from an exact matching engine to query the OWL(Web Ontology Language) MIT Process Handbook. MIT Process Handbook is an electronic repository of best-practice business processes. The Handbook is intended to help people: (1) redesigning organizational processes, (2) inventing new processes, and (3) sharing ideas about organizational practices. In order to use the MIT Process Handbook for process retrieval experiments, we had to export it into an OWL-based format. We model the Process Handbook meta-model in OWL and export the processes in the Handbook as instances of the meta-model. Next, we need to find a sizable number of queries and their corresponding correct answers in the Process Handbook. Many previous studies devised artificial dataset composed of randomly generated numbers without real meaning and used subjective ratings for correct answers and similarity values between processes. To generate a semantic-preserving test data set, we create 20 variants for each target process that are syntactically different but semantically equivalent using mutation operators. These variants represent the correct answers of the target process. We devise diverse similarity algorithms based on values of process attributes and structures of business processes. We use simple similarity algorithms for text retrieval such as TF-IDF and Levenshtein edit distance to devise our approaches, and utilize tree edit distance measure because semantic processes are appeared to have a graph structure. Also, we design similarity algorithms considering similarity of process structure such as part process, goal, and exception. Since we can identify relationships between semantic process and its subcomponents, this information can be utilized for calculating similarities between processes. Dice's coefficient and Jaccard similarity measures are utilized to calculate portion of overlaps between processes in diverse ways. We perform retrieval experiments to compare the performance of the devised similarity algorithms. We measure the retrieval performance in terms of precision, recall and F measure? the harmonic mean of precision and recall. The tree edit distance shows the poorest performance in terms of all measures. TF-IDF and the method incorporating TF-IDF measure and Levenshtein edit distance show better performances than other devised methods. These two measures are focused on similarity between name and descriptions of process. In addition, we calculate rank correlation coefficient, Kendall's tau b, between the number of process mutations and ranking of similarity values among the mutation sets. In this experiment, similarity measures based on process structure, such as Dice's, Jaccard, and derivatives of these measures, show greater coefficient than measures based on values of process attributes. However, the Lev-TFIDF-JaccardAll measure considering process structure and attributes' values together shows reasonably better performances in these two experiments. For retrieving semantic process, we can think that it's better to consider diverse aspects of process similarity such as process structure and values of process attributes. We generate semantic process data and its dataset for retrieval experiment from MIT Process Handbook repository. We suggest imprecise query algorithms that expand retrieval results from exact matching engine such as SPARQL, and compare the retrieval performances of the similarity algorithms. For the limitations and future work, we need to perform experiments with other dataset from other domain. And, since there are many similarity values from diverse measures, we may find better ways to identify relevant processes by applying these values simultaneously.