• Journal of Korean Society for Quality Management
• /
• v.17 no.2
• /
• pp.17-26
• /
• 1989

This paper is concerned with forecasting the existing number of errors in the computer software and optimizing the stopping time of the software test based upon the forecasted number of errors. The most commonly used models have assessed software reliability under the assumption that the software failure late is proportional to the current fault content of the software but invariant to time since software faults are independents of others and equally likely to cause a failure during testing. In practice, it has been observed that in many situations, the failure rate decrease. Hence, this paper proposes a mathematical model to describe testing situations where the failure rate of software limearly decreases proportional to testing time. The least square method is used to estimate parameters of the mathematical model. A cost model to optimize the software testing time is also proposed. In this cost mode two cost factors are considered. The first cost is to test execution cost directly proportional to test time and the second cost is the failure cost incurred after delivery of the software to user. The failure cost is assumed to be proportional to the number of errors remained in the software at the test stopping time. The optimal stopping time is determined to minimize the total cost, which is the sum of test execution cast and the failure cost. A numerical example is solved to illustrate the proposed procedure.

• Journal of Distribution Research
• /
• v.1 no.1
• /
• pp.239-258
• /
• 1996

This study deals with the measurement of relational norms, a safeguard for sustained exchange relationshipsim marketing channel systems. Here, the relational norm items are hypothesized to have a second-order factor model, in which mine observed items originate from the three first-order factors and the first order factors in turn originate from a second-order factor. The three first order construe comprising a higher order norm are mutuality(equity in the distribution of benefits and burdens over the course of the exchange on a long term basis), flexibility(expectation of friendly adaption for possible circumstance changes), and solidarity (the degree to which the preservation of the unique and continuing relationship is internalized by the exchange partners as being important in and of itself). 113 research questionnaires are obtained from four industries such as construction, telecommunication, iron, and electric ＆ electronic industries, Reliability and nomological. discriminant validity are tested, and in using the confirmatory factor analysis of Lisrel 7.16, and the chi-square difference test it is tested which has a better satisfactory fit to the data, the first-order model or the second-order one. The results of this study indicates that relational norms have a second order construct. In the electric and electronic industry the model as a while has a satisfactory fit to the data and the relevant first- and second-order factor loading to the mutuality is not significant. Same Results are happened to the flexibility in the telecommunication industry and to the mutuality and flexibility in the inn industry. In sum, the model lends support to our construct, but it is difficult to apply the measurement model to all kinds of industries.

• Health Policy and Management
• /
• v.13 no.2
• /
• pp.23-43
• /
• 2003

The purpose of this study was to explore the determinants of induced abortions of married women in Korea, with focus on the socioeconomic factors including fertility behaviors and ideation regarding family values. Data from the 2000 Korea National Fertility Survey by Korea Institute of Health and Social Affairs were used for the research. In particular, the women´s fertility history from 1998 to 2000 was served as the main data for this study. Among 1,901 pregnancies in total, 1,612 pregnancy outcomes were selected for the final analysis. Chi-square test, Wilcoxon rank sum test and multivariate logistic regressions were employed to identify influential factors on induced abortions. According to the results, working women was more likely than those who did not work to terminate their pregnancy by an induced abortion. Women´s religion did not show any significant impact on an induced abortion. A pregnant woman already having more than or equal to two children was very likely to choose an induced abortion. Likewise, those in unwanted pregnancy showed high probability of induced abortions. However, contrary to what we believe, it turned out that the number of sons did not affect the choice of induced abortions.

• Korean Journal of Computational Design and Engineering
• /
• v.4 no.3
• /
• pp.173-179
• /
• 1999

In reverse engineering, when a shape containing multi-patched surfaces is digitized, the boundaries of these surfaces should be detected. The objective of this paper is to introduce a computationally efficient segmentation technique for extracting edges, ad partitioning the 3D measuring point data based on the location of the boundaries. The procedure begins with the identification of the edge points. An automatic edge-based approach is developed on the basis of local geometry. A parametric quadric surface approximation method is used to estimate the local surface curvature properties. the least-square approximation scheme minimizes the sum of the squares of the actual euclidean distance between the neighborhood data points and the parametric quadric surface. The surface curvatures and the principal directions are computed from the locally approximated surfaces. Edge points are identified as the curvature extremes, and zero-crossing, which are found from the estimated surface curvatures. After edge points are identified, edge-neighborhood chain-coding algorithm is used for forming boundary curves. The original point set is then broke down into subsets, which meet along the boundaries, by scan line algorithm. All point data are applied to each boundary loops to partition the points to different regions. Experimental results are presented to verify the developed method.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.7C
• /
• pp.562-568
• /
• 2008

This paper proposes the scheme which obtain the coefficients of TDL filter and two normalization algorithms among methods which get solution of equivalent Wiener-Hopf Equation in Gram-Schmidt algorithm. Compared to the conventional NLMS algorithm, normalizes with sum of power of inputs, the presented algorithms normalize using sums of eigenvalues. Using computer simulation, we perform an system identification in an unstable environment where two poles are located in near position outside unit circle. Consequently, the proposed algorithms get the coefficients of TDL filter in Gram-Schmidt algorithm recursively and show better convergence performance than conventional NLMS algorithm.

• Journal of Korean Public Health Nursing
• /
• v.23 no.2
• /
• pp.153-161
• /
• 2009

Purpose: This study was done to evaluate the differences between an experimental group and a control group of nursing students for their knowledge of CPR and their practical ability after undergoing CPR training. Method: This experiment was done with nursing students, who are divided into the experimental group (20 students) and the control group (23 students) in Chunbuk C city. The data were analyzed using the SPSS PC+ 12.0 program for the Chi-square tests, t-tests and Wilcoxon rank sum tests. Results: The 1st hypothesis, that the CPR knowledge scores for the experimental group will be higher than the scores for the control group (t=-3.934, p=<.001), was supported. On the other hand, the control group showed a conspicuous and meaningful improvement (t=-3.932, p=<.001). The 2st hypothesis, that the practical ability scores for the experimental group will be higher than the scores for the control group (t=-3.926, p=<.001), was supported. Conclusion: The CPR training in combination with theory and clinical placement is seen as a means to effectively develop the knowledge and practical ability of CPR.

• Journal of muscle and joint health
• /
• v.20 no.2
• /
• pp.122-130
• /
• 2013

Purpose: The purpose of this study was to investigate differences in vaccination status and awareness between influenza and pneumococcal vaccinations in the elderly. Methods: This cross-sectional study was used with a questionnaire. Data were collected from 107 older people over 65 years registered at one community center in December, 2012. The data were analysed with Chi-square, Fisher's exact-test, Wilcoxon Signed rank sum test, Mann-Whitney U test, and Kruskall-Wallis test. Results: There were significant differences in the experiences of vaccination and reason for unvaccination by vaccine types. The mean scores for awareness of vaccination were 1.81 (range 0~3) in influenza and 1.50 in pneumococcus (range 0~3). There was a significant difference in awareness by vaccine types (Z=6.12, p<.001). There was a positive association between influenza and pneumococcal vaccination awareness (rho=.236, p=.014). Conclusion: This study showed different vaccination status and awareness in vaccine types. It is necessary to consider vaccination status and awareness by vaccine types of the target population in the education program related to vaccination.

• Research in Community and Public Health Nursing
• /
• v.21 no.2
• /
• pp.252-262
• /
• 2010

Purpose: Designed to examine the effects of aerobic exercise therapy on elders' physical functions. Methods: Selected from an elderly welfare center in an agricultural district located in N City. Thirty seven elders were selected in the experimental group and 38 in the control group, and all the subjects aged over 65. Collected data were statistically analyzed by SPSS/PC 12.0 Win. Detailed data analysis methods were Chi-square, Fisher's exact test, Kolmogorov-Smirnov test, t-test, Mann-Whitney u-test, paired t-test, and Wilcoxon's rank sum test. Results: The first hypothesis "The experimental group who had the aerobic exercise therapy will have greater development in lower leg muscular strength compared to the control group" was supported (t=8.95, p<.001). The second hypothesis "Aerobic exercise therapy participants will show greater development in lower leg endurance" was supported (t=6.12, p<.001). The third hypothesis "Aerobic exercise therapy participants will show greater development in flexibility" was supported (U=49.00, p<.001). The forth hypothesis "Aerobic exercise therapy participants will show greater development in balance" was supported (U=322.00, p<.001). Conclusion: The aerobic exercise therapy showed positive effects on physical functions of the elderly in a rural area.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.38 no.1
• /
• pp.69-87
• /
• 2013

Recently a large number of people have been using social networking and microblogging services such as Facebook and Twitter. These mediums play a pivotal communication channel in a business-to-customer (B2C) relationship. Given its importance in today's business, companies have invested in the strategic application of social network services to reach out to customers. This study provides a blueprint for mechanisms for successful execution of social network services in the context of developing an effective B2C relationship, such as customer participation behavior. The S-O-R(Stimulus-Organism-Response) framework lays out the foundation for developing our research model and provides a structured view for understanding customer participation behavior on brand loyalty. For the methodology, this study employed a mixed-method approach. Additionally, in order to provide empirical evidences, a total of 121 respondents have completed the survey. All the data were compiled and analyzed through structural equation modeling and were implemented in partial least square (PLS). To sum up, this study presented theoretical and practical implications by providing the effect of customer participation behavior on brand loyalty through B2C microblogging.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.21 no.9
• /
• pp.828-833
• /
• 2011

A reaction wheel assembly(RWA) is the largest disturbance source that can induce high frequency micro-vibration on an optical payload of satellites. To ensure a tight pointing-stability budget of satellites, the RWA disturbance effect on spacecraft should be accurately analyzed and evaluated for whole design phases. For this purpose, the micro-vibration disturbance of RWA should be precisely measured. In the present study, two measurement methods on RWA micro-vibration disturbances are compared and investigated. One is a free run-down speed test and the other is a constant speed test. The micro-vibration data measured by the two methods are analyzed in terms of spectrum characteristics, static and dynamic imbalance values, and root sum square(RSS) values. The analysis results show that both methods can measure very similar results in time and frequency domains and that the free run-down speed method is more adequate in respects to wheel friction modeling, noise rejection of imbalance and RSS peak evaluation.