• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.139-149
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• 2010

Internet was designed for network scalability and best-effort service which makes all hosts connected to Internet to be vulnerable against attack. Many papers have been proposed about attack detection algorithms against the attack using IP spoofing and DoS/DDoS attack. Purpose of DoS/DDoS attack is achieved in short period after the attack begins. Therefore, DoS/DDoS attack should be detected as soon as possible. Attack detection algorithms using false alarm rates consist of the false negative rate and the false positive rate. Moreover, they are important metrics to evaluate the attack detections. In this paper, we analyze the performance of the attack detection algorithms using the impact of false negative rate and false positive rate variation to the normal traffic and the attack traffic by simulations. As the result of this, we find that the number of passed attack packets is in the proportion to the false negative rate and the number of passed normal packets is in the inverse proportion to the false positive rate. We also analyze the limits of attack detection due to the relation between the false negative rate and the false positive rate. Finally, we propose a solution to minimize the limits of attack detection algorithms by defining the network state using the ratio between the number of packets classified as attack packets and the number of packets classified as normal packets. We find the performance of attack detection algorithm is improved by passing the packets classified as attacks.

• The Journal of Bigdata
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• v.3 no.2
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• pp.101-112
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• 2018

The purpose of the study is to predict the number of police calls using neural network which is one of the machine learning and negative binomial regression, by using the data of 112 police calls received from Chungnam Provincial Police Agency from June 2016 to May 2017. The variables which may affect the police calls have been selected for developing the prediction model : time, holiday, the day before holiday, season, temperature, precipitation, wind speed, jurisdictional area, population, the number of foreigners, single house rate and other house rate. Some variables show positive correlation, and others negative one. The comparison of the methods can be summarized as follows. Neural network has correlation coefficient of 0.7702 between predicted and actual values with RMSE 2.557. Negative binomial regression on the other hand shows correlation coefficient of 0.7158 with RMSE 2.831. Neural network has low interpretability, but an excellent predictability compared with the negative binomial regression. Based on the prediction model, the police agency can do the optimal manpower allocation for given values in the selected variables.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.154-168
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• 2021

COVID-19 has been spreading all around the world, and threatening global health. In this situation, identifying and isolating infected individuals rapidly has been one of the most important measures to contain the epidemic. However, the standard diagnosis procedure with RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) is costly and time-consuming. For this reason, pooled testing for COVID-19 has been proposed from the early stage of the COVID-19 pandemic to reduce the cost and time of identifying the COVID-19 infection. For pooled testing, how many samples are tested in group is the most significant factor to the performance of the test system. When the arrivals of test requirements and the test time are stochastic, batch-service queueing models have been utilized for the analysis of pooled-testing systems. However, most of them do not consider the false-negative test results of pooled testing in their performance analysis. For the COVID-19 RT-PCR test, there is a small but certain possibility of false-negative test results, and the group-test size affects not only the time and cost of pooled testing, but also the false-negative rate of pooled testing, which is a significant concern to public health authorities. In this study, we analyze the performance of COVID-19 pooled-testing systems with false-negative test results. To do this, we first formulate the COVID-19 pooled-testing systems with false negatives as a batch-service queuing model, and then obtain the performance measures such as the expected number of test requirements in the system, the expected number of RP-PCR tests for a test sample, the false-negative group-test rate, and the total cost per unit time, using the queueing analysis. We also present a numerical example to demonstrate the applicability of our analysis, and draw a couple of implications for COVID-19 pooled testing.

• Korean Journal of Plant Resources
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• v.36 no.3
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• pp.225-236
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• 2023

Stomatal traits such as stomata density (SD), aperture length (APL) and width (APW), guard cell length (GCL) and width (GCW), and distance between stomata (DIS) were investigated to identify correlation with agronomic traits for 35 Korean wheat cultivars. Flag leaf width (FLW) of Korean wheat cultivars was the widest in Ol-mil, and the narrowest in Keumkang. SD tended to be higher on the adaxial side than on the abaxial side in Korean wheat cultivars. SD of adaxial and abaxial sides was classified into a cultivar with a significantly different or not. In APL, 18 wheat cultivars showed significant differences according to leaf side, and APL of adaxial was longer than APL of abaxial in 13 wheat cultivars. In APW, 15 wheat cultivars showed a significant difference, and APW of abaxial was wider than APW of adaxial among them. In GCL, 14 wheat cultivars showed a significant difference, and the GCL of abaxial was longer than the GCL of adaxial in 10 wheat cultivars. In GCW, 10 wheat cultivars showed a significant difference, GCW of adaxial was wider than GCW of abaxial and in 6 wheat cultivars. FLW of adaxial and abaxial showed a negative correlation with GCL and a positive correlation with grain number per panicle. FLW of only abaxial showed a positive correlation with DIS. The SD of the adaxial showed a negative correlation with GCL, while the SD of the abaxial showed a negative correlation with APL. APL of both sides of the leaf showed a positive correlation with GCL, and APW of only abaxial showed a negative correlation with GLC. DIS of adaxial showed a negative correlation with tiller number (TN), while DIS of abaxial showed a positive correlation with GNP.

• Journal of Families and Better Life
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• v.34 no.2
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• pp.65-83
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• 2016

The purpose of this study was to investigate the influences of variables related to family and employment on work-family negative spillover. The subjects of this study were 570 dual-earner with children. The research tool was questionnaires. For data analysis, factor analysis, Cronbach ${\alpha}$, and multiple regression were performed. The main results of this study were as following. First, among variables related to family, spouse support, parental satisfaction, marital satisfaction, perceived fairness in the division of household labor, daily housework hour and family strengths had an influence on $work{\rightarrow}family$ negative spillover in wives, and weekends housework hour, perceived fairness in the division of household labor, perception of the gender role, and satisfaction of the division in household labor had an influence on $work{\rightarrow}family$ negative spillover in husband. Second, among variables related to family, parental satisfaction, number of children influence on $family{\rightarrow}work$ negative spillover in wives, and spouse support, parental satisfaction, satisfaction of the division in household labor, marital satisfaction, and perception of the gender role had an influence on $family{\rightarrow}work$ negative spillover in husband. Third, among variables related to employment, support from workplace, weekly working hour, monthly income, and job satisfaction had an influence on $work{\rightarrow}family$ negative spillover in wives, and support from workplace, monthly income, household income, and weekly working hour had an influence on $work{\rightarrow}family$ negative spillover in husband. Forth, among variables related to employment, support from workplace in wives, and job satisfaction in husband had an influence on $family{\rightarrow}work$ negative spillover. To conclude, there was some difference in the variables influencing $work{\rightarrow}family$, $family{\rightarrow}work$ negative spillover between wife and husband. So, We have to take this difference into consideration in establishing work-family life balance policies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.381-387
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• 2002

Curved bridges are composed of curved members which have certain curvatures, comparing to straight bridges. Therefore, their behavior is quite different from one of the straight bridges, mainly due to the geometric characteristics of the curved bridges. In this paper, the curved bridges consisted of the single box-girder span are investigated to study the effects of negative reaction forces. The parameters considered in this study are span lengths, angles of curvature, and the number of shoes. Midas/civil computer program was used for the analysis of the curved bridges. The analysis results show that negative reaction forces are not created with one shoe installed. When two shoes are provided, on the other hands, the uplift forces are developed at the inside shoe. It is also concluded that the increasing ratio of negative reaction forces becomes larger, as the angles of curvature increase, and the elongation of span lengths turns out to increase the magnitudes of the uplift forces.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.87-97
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• 2019

Reaction of people is importantly considered about specific case as a social network service grows. In the previous research on analysis of social network service, they predicted tendency of interesting topic by giving scores to sentences written by user. Based on previous study we proceeded research of sentiment analysis for social network service's sentences, which predict the result as positive or negative for movie reviews. In this study, we used movie review to get high accuracy. We classify the movie review into positive or negative based on the score for learning. Also, we performed embedding and morpheme analysis on movie review. We could predict learning result as positive or negative with a number 0 and 1 by applying the model based on learning result to social network service. Experimental result show accuracy of about 80% in predicting sentence as positive or negative.

• The Journal of Korean Academic Society of Nursing Education
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• v.11 no.2
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• pp.161-168
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• 2005

Purpose: The purposes are to identify the factors that influence work-based stressor experienced by clinical nurses and to provide a perceived causal structural model among these factors. Method: Data was collected and analyzed in 2 steps to apply a perceived causal structure : network analysis which was developed by Kelley(1983). Results: 1. The extracted causes from qualitative data were identified 10 categories ; over loaded work, relative feelings of deprived, inefficient duty schedule, negative attitudes of patient, burden of extra affair, inadequate administrative support, negative attitudes of physician, conflict with other personnels in hospital, lack of professional knowledge and skill, nursing service marketing burden. 2. Construction of the perceived causal structural model ; 1) The most central cause is over loaded work and the distal causes were inadequate administrative support, lack of professional knowledge and skill in the systems of causation. 2) The causes that have a number of outgoing link were over loaded work, inadequate administrative support, negative attitudes of physician. 3) The cause that have a number of incoming link was relative feelings of deprived. Conclusion: The network suggests that the first centre cause was related on over loaded work.

• The Journal of Korean Medicine
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• v.41 no.3
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• pp.55-65
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• 2020

Objectives: This study aimed to evaluate the toxicity of CP pharmacopunture using bacterial reverse mutation test. Methods: To determine the mutagenic potential of CP pharmacopunture, histidine requiring Salmonella typhimurium (TA98, TA100, TA1535, and TA1537) and tryptophan requiring Escherichia coli (WP2uvrA, pKM101) strains were used. The negative (normal saline solution) and positive (Sodium azide, 2-Nitrofluorene, 2-Aminoanthracene, 9-Aminoacridine, and 4-Nitroquinoline N-oxide) control groups were used. To determine the dose levels of the main study, a dose range-finding study was conducted. Results: As a results of the dose range-finding study, the growth inhibition by CP pharmacopunture was not evident at any dose levels in the absence and presence of metabolic activation. As a results of the main study, the mean number of revertant colonies was less than twice when compared to the negative control values at all dose levels of the CP pharmacopuncture in the presence and absence of metabolic activation, showing no dose-related increase. In the positive control group, the number of revertant colonies was markedly increased by more than twice when compared to the negative control group. Conclusion: According to the results of this study, CP pharmacopunture did not show any signs of mutagenic potential.

• International Journal of Highway Engineering
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• v.20 no.2
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• pp.119-126
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• 2018

PURPOSES : The purpose of this study is to develop a crash prediction model at signalized intersections, which can capture the randomness and uncertainty of traffic accident forecasting in order to provide more precise results. METHODS : The authors propose a random parameter (RP) approach to overcome the limitation of the Count model that cannot consider the heterogeneity of the assigned locations or road sections. For the model's development, 55 intersections located in the Daejeon metropolitan area were selected as the scope of the study, and panel data such as the number of crashes, traffic volume, and intersection geometry at each intersection were collected for the analysis. RESULTS : Based on the results of the RP negative binomial crash prediction model developed in this study, it was found that the independent variables such as the log form of average annual traffic volume, presence or absence of left-turn lanes on major roads, presence or absence of right-turn lanes on minor roads, and the number of crosswalks were statistically significant random parameters, and this showed that the variables have a heterogeneous influence on individual intersections. CONCLUSIONS : It was found that the RP model had a better fit to the data than the fixed parameters (FP) model since the RP model reflects the heterogeneity of the individual observations and captures the inconsistent and biased effects.