• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.325-332
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• 2017

In this paper, a survey of test sequence generation methods for testing the conformance of a protocol implementation to its specification is presented. The best known methods proposed in the literature are called transition tour, distinguishing sequence, characterizing sequence, and unique input/output sequence. Also, several variants of the above methods are introduced. Applications of these methods to the finite state machine model are discussed. Then, comparative analysis of the methods is made in terms of test sequence length. Finally, conclusions are given as follows. The T-method produces the shortest test sequence, but it has the worst fault coverage. The W-method tends to produce excessively long test sequences even though its fault coverage is complete. The problem with the DS-method is that a distinguishing sequence may not exist. The UIO-method is more widely applicable, but it does not provide the same fault coverage as the DS-method.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1294-1303
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• 1999

The purpose of this study was to develop a tool to assess the powerlessness and to measure the powerlessness of elderly. From the result of pre-test, twenty seven items were finally selected to survey the elderly's powerlessness. The questionnaires on the elderly's powerlessness were drafted so that such tool may be evaluated in accordance with the four point Likert Scale. The number of subjects is 1,150 with ages of 60 years or more and who live in a large city, a small and middle-sized city and a rural area. The subjects of the test and retest were 85 elderlies. Collected data were analyzed by utilizing SAS program with Cronbach's $\alpha$ and Pearson's correlation, factor analysis method and known group techniques, descriptive statics, t-test and ANOVA. The results from this study were summarized below:1. When the factor analysis method was applied for validity, the tool for powerlessness of elderly was separated into 5 factors: loss of self-confidence to deal with physical, emotional, social aspects of life; expulsion by others from meaningful human relate; perception that life is meaningless and time passes quickly; falling behind young people; being rejected by other people, having no influence on others. An application of the known group technique showed a significant difference with the result of the degree of elderly's powerlessness tools developed by the two groups, with illness and without. 2. In testing reliability, it was found that coefficient of test-retest was .9435(P<.0001) when the test-retest method was used as a test of stability, and that the alpha coefficient of internal consistency was .9141 over all items within the tool of elderly's powerlessness 3. In powerlessness of elderly, total mean is 2.8493. And in factor of powerlessness, the highest factor is falling behind young people (M=3.1713), the lowest factor is loss of self- confidence to deal with physical, emotional, social aspects of life(M=2.6080). 4. The results from the test for the degree of powerlessness, according to the subject's demographic variables, showed that there were significant differences between age, sex, marital status, educational level, religion, possession of house, job, monthly pocket money, health status, illness and a place of residence.

• Journal of Korean Academy of Nursing
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• v.30 no.4
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• pp.1055-1065
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• 2000

The purpose of this study was to develop, through the integration of instructional theory, a Courseware and to investigate the effectiveness of a web-based computer assisted instruction(WBI) program for preventing drug abuse, a serious problem for youth problem. During the first stage of this study done "Drug Abuse Prevention" Courseware was developed based on, Gagn & Brigg's instructional design theory, Keller's ARCS theory and the CAI model of Hannafin & Peck. For the second stage, the courseware was used to provide education for students adolescents in drug abuse prevention. This study used an quasi-experimental, one-group pretest-posttest design with a convenience sample of 36 male high school students who were at one high school located in Seoul. Data were collected using self-reported questionnaires which included a learning achievement tool, the Keller's IMMS (Instructional Material Motivation Survey), on attitudes to drug use, and on responses to the WBI instruction. Prior to the experiment, the "drug abuse prevention" learning method and the procedures of the study were explained to the students, and then the learning achievement of the subjects was measured as a pretest. The students were then given 2 weeks WBI utilizing the courseware. A post-test which included the pre-test learning achievement questionnaire and a survey of learning motivation and attitudes toward drug were given two weeks after the education was completed. The data analysis was done using SPSS/PC. Paired t-test was used to analyze the differences between the pre-test and post-test scores for learning achievement. The results of the analysis are as follows: There were significant differences in learning achievement between the pre-test and post-test(t=-18.62, p=0.000). The hypothesis, that learning achievement will be higher, after the class has used the courseware, than before was supported. The scores for learning motivation and attitudes toward drugs were also higher than the results of existing studies. In conclusion, this study suggests that WBI is an effective learning method in the prevention of drug abuse for adolescents as it can be used for self-learning and repeated learning as assisted instruction. Recommendation would be given that further research needs to be develped in the courseware by cognitive learning style and by multimedia courseware and virtual reality system.

• Journal of the Korean Society of Earth Science Education
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• v.17 no.2
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• pp.168-180
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• 2024

In this study, we developed a STEAM program based on digital astronomical and space resources and applied it to 167 randomly selected elementary school students to examine the effectiveness of the STEAM program in enhancing creative problem solving skills. The results of this study are as follows: first, the statistical analysis of pre-test and post-test scores for creative problem-solving skills related to the STEAM program showed significant results (p<.05). This suggests that the STEAM program contributed to improving creative problem-solving skills through the procedural process involved in generating ideas and convergent thinking during the digital problem-solving. Second, the paired sample t-test based on the pre-test and post-test of the STEAM attitude test also showed significant results (p<.05). Analyzing digital materials and presenting pixel art projects positively influenced STEAM attitudes in terms of interest, communication, and usefulness. This underscores the need for developing integrative education programs utilizing advanced technologies in the future. Third, in the class satisfaction test conducted after the application of the STEAM program, the satisfaction factor scored an average of 3.55, interest scored 3.35, and overall class difficulty scored 3.46. The main difference from traditional classes was the focus on 'acquisition of future career information.' However, given the slight decrease in interest during the digital transformation and interpretation process, it is recommended that future classes allocate sufficient time for experiential activities. To generalize the developed program, future studies should consider various school levels, implementation periods, and difficulty levels.

• Composites Research
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• v.33 no.3
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• pp.115-124
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• 2020

Laminate composites, especially Carbon fiber-reinforced composites are wide used in various industry such as aerospace and automotive industry due to their high specific strength and specific stiffness. However, the laminate composites has a big disadvantage that delamination occurs because the arrangement of the fibers is all arranged in the in-plane direction, which limits the field of application of the laminate composites. In this study, we first developed a laminate composites T-beam in which π-beam and flat plate were combined and optimized the design parameters through structural analysis and mechanical tests. Afterwards, 3D weave preform T-beam was developed by applying the same design parameters of laminate composites T-beams, and improved mechanical strength was achieved compared to laminated structures. These findings are expected to be applicable to existing laminated composite structures that require increased strength.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.514-521
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• 2018

COSPAS-SARSAT 406 MHz emergency beacons include ELTs for aviation, EPIRBs for maritime, and PLBs for individuals in distress. They are used to sending messages encoded on 406 MHzdistress frequency and sending alertsfor search and rescue in distress. C/S T.001 and T.018 are COSPAS-SARSAT technical documents. They include basic technical information needed for developing beacons, howmessages are constructed, and test methods for type approval. COSPAS-SARSAT systems that use existing low earth orbit (LEO) and geostationary earth orbit (GEO) satellites do not have a return link service (RLS). So, the survivors could not confirm whether the distress signal was sending or not. However, a new medium earth orbit (MEO)satellite system has been added to thissystem, allowing confirmation through the RLS function. This paper analyzed C/S T.001 and T.018 needed to develop navigation structuresthat incorporated improved PLB of 406 MHz, a homing signal generator of 121.5 MHz, and a VHF AM transmitter for aviation of 243 MHz.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.3
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• pp.1-15
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• 2016

This study has analyzed predication capabilities leveraging multi-variate model, logistic regression model, and artificial neural network model based on financial information of medium-small sized companies list in KOSDAQ. 83 delisted companies from 2009 to 2012 and 83 normal companies, i.e. 166 firms in total were sampled for the analysis. Modelling with training data was mobilized for 100 companies inlcuding 50 delisted ones and 50 normal ones at random out of the 166 companies. The rest of samples, 66 companies, were used to verify accuracies of the models. Each model was designed by carrying out T-test with 79 financial ratios for the last 5 years and identifying 9 significant variables. T-test has shown that financial profitability variables were major variables to predict a financial risk at an early stage, and financial stability variables and financial cashflow variables were identified as additional significant variables at a later stage of insolvency. When predication capabilities of the models were compared, for training data, a logistic regression model exhibited the highest accuracy while for test data, the artificial neural networks model provided the most accurate results. There are differences between the previous researches and this study as follows. Firstly, this study considered a time-series aspect in light of the fact that failure proceeds gradually. Secondly, while previous studies constructed a multivariate discriminant model ignoring normality, this study has reviewed the regularity of the independent variables, and performed comparisons with the other models. Policy implications of this study is that the reliability for the disclosure documents is important because the simptoms of firm's fail woule be shown on financial statements according to this paper. Therefore institutional arragements for restraing moral laxity from accounting firms or its workers should be strengthened.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.167-172
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• 1999

Purpose : To evaluate the detection rate of hyperacute intracerebral hemorrhage in echo planar imaging (EPI) and other MR sequences. materials and Methods : Intracerebral hemorrhage was experimentally induced in ten rats. EPI, fast spin-echo (FSE) T2 weighted images, fluid attenuated inversion recovery (FLAIR), spin-echo (SE) T1 weighted images and gradient echo (GE) T1 weight ed images of rat's brains were obtained 2 hours after onset of intracerebral hemorrhage. EPI and FSE T2 images were additionally obtained 30 min and 1 hour after onset of hemorrhage in 3 and 6 rat, repeatedly, For objective visual assessment, discrimination between the lesion and normal brain parenchyma was evaluated on various MR sequences by three radiologists. For quantitative assessment, contrast-to-noise ratio (CNR) was calculated fro hemorrhage-normal brain parenchyma. Statistical analysis was performed usning the Wilcoxon-Ranks test. Results : EPI, FLAIR, and FSE T2 images showed high signal intensity lesions. The lesion discrimination was easier on EPI than on other sequences, and also EPI showed higher signal intensity for the subjective visual assessment. In quantitative evaluation, CNR of the hemorrhagic lesion versus normal brain parenchyma were higher on EPI and FLAIR images (p<0.01). There was no difference in CNR between EPI and FLAIR (p>0.10). On MR images obtained 30 minutes and 1 hour after the onset of intracerebral hemorrhage, the lesion detection was feasible on both EPI and FSE T2 images showing high signal intensity. Conclusion : EPI showed higher detection rate as compared with other MR sequences and could be useful in early detection and evaluation of intracerebral hemorrhage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.315-324
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• 2020

The purpose of this study was to examine the relationship between emotional traumatic experience, stress, depression, and anxiety and to identify factors influencing suicide ideation. Data collection was carried out using a questionnaire survey administered to students from four health colleges in B city and a total of 289 questionnaires. Collected data were analyzed by frequency and percentage, mean, standard deviation, t-test, ANOVA, and multiple regression analysis using the SPSS/WIN program. The results show that there were significant differences in emotional trauma according to the general characteristics of the study subjects (p=.005) and stress related to grades (p=.029). Depression showed significant differences for gender (p=.020), religion (p=.022), and anxiety related to gender (p=.047). Suicidal thinking was not significantly different from the general characteristics. The suicidal ideation of the subjects was significantly correlated with emotional trauma (p<.001), stress (p<.001), depression (p<.001) and anxiety (p<.001). Factors affecting the suicidal ideation of the subjects were emotional trauma (t=4.117, p<.001), stress (t=2.909, p=.004), depression (t=3.421, p=.001), and anxiety (t=2.875, p=.004), and the explanatory power was 34.1%. This study can be used as basic data for the development of a suicide prevention program by identifying correlations between emotional traumatic experience, stress, depression, and anxiety related to suicide ideation and identifying factors affecting suicide ideation. Based on these results, the development of programs to reduce the college student suicide rate is necessary.

• Journal of Gastric Cancer
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• v.1 no.2
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• pp.77-82
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• 2001

Purpose: The most important prognostic factors in gastric cancer are depth of invasion and lymph node metastasis. Therefore, the prognosis for serosa and lymph node negative gastric cancer is favorable. However, there is no general agreement on the prognostic factors in this subset of patients. This study was undertaken to evaluate the prognostic significances of venous invasion (VI), lymphatic invasion (LI), and perineural invasion (NI) in T1 and T2 gastric cancer without lymph node involvement. Materials and Methods: We retrospectively evaluated 206 patients with T1 and T2, lymph node negative gastric cancer who underwent a curative resection from 1989 to 1993 at Kangnam St. Mary's Hospital, Seoul, Korea. The Chi-square test was used to determine the statistical significance of differences, and the Kaplan-Meier method was used to calculate survival rates. Significant differences in the survival rates were assessed using the log-rank test, and the Cox regression method was used to evaluate independent prognostic significance. Results: The rate of VI, LI and NI correlated well with the depth of tumor invasion. The rates of VI (+) for T1 vs T2 was $0\%\;vs\;5.1\%$, of LI (+) was $5.6\%\;vs\;26.8\%$, and of NI (+) was $1.6\%\;vs\;26.8\%$ in NI (+). There were 13 recurrent cases, 10 cases out of the 13 were T2 gastric cancers, and the recurrence rate was higher in LI (+) and NI (+) cases than in LI (-) and NI (-) cases. The 5-year survival rates were $93.4\%$ in LI (-) cases, $77.4\%$ in LI (+) cases, $92.5\%$ in NI (-) cases, $74\%$ in NI(+) cases, $95.9\%$ in LI (-) NI (-) cases, and $73.9\%$ in LI (+) NI (+) cases. Multivariate analysis demonstrated that simultaneous LI and NI was the only significant factor influencing the prognosis. Conclusion: These results suggest that simultaneous lymphatic and perineural invasion may be an independent prognostic factor in patients with T1 and T2 gastric cancer without lymph node metastasis.