• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.3076-3092
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• 2020

An IKPCA-ELM-based intrusion detection method is developed to address the problem of the low accuracy and slow speed of intrusion detection caused by redundancies and high dimensions of data in the network. First, in order to reduce the effects of uneven sample distribution and sample attribute differences on the extraction of KPCA features, the sample attribute mean and mean square error are introduced into the Gaussian radial basis function and polynomial kernel function respectively, and the two improved kernel functions are combined to construct a hybrid kernel function. Second, an improved particle swarm optimization (IPSO) algorithm is proposed to determine the optimal hybrid kernel function for improved kernel principal component analysis (IKPCA). Finally, IKPCA is conducted to complete feature extraction, and an extreme learning machine (ELM) is applied to classify common attack type detection. The experimental results demonstrate the effectiveness of the constructed hybrid kernel function. Compared with other intrusion detection methods, IKPCA-ELM not only ensures high accuracy rates, but also reduces the detection time and false alarm rate, especially reducing the false alarm rate of small sample attacks.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.11-18
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• 2012

In this paper, an entropy constrained vector quantizer for high bit-rates is proposed. The sample-adaptive product quantizer (SAPQ), which is based on the product codebooks, is employed, and a design algorithm for the entropy constrained sample adaptive product quantizer (ECSAPQ) is proposed. The performance of the proposed ECSAPQ is better than the case of the entropy constrained vector quantizer by 0.5dB. It is also shown that the ECSAPQ distortion curve, which is based on the scalar quantizer, is lower than the high-rate theoretical curve of the entropy constrained scalar quantizer, where the theoretical curve have 1.53dB difference from Shannon's lower bound.

• Nuclear Engineering and Technology
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• v.40 no.2
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• pp.99-106
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• 2008

Through mechanical alloying, hot isostatic pressing and hot rolling, a 9%Cr Fe-based oxide dispersion-strengthened alloy sample was fabricated. The tensile strength of the alloy is significantly improved when the microstructure is modified during the post-consolidation process. The alloy samples were strengthened as the cooling rates increased, though the elongation was somewhat reduced. With a cooling rate of $800^{\circ}C/s$ after normalization at $1150^{\circ}C$, the alloy sample showed a tensile strength of 1450 MPa, which is about twice that of the hot rolled sample; however, at $600^{\circ}C$ the tensile strength dramatically decreased to 620 MPa. Optical microscope and transmission electron microscope were used to investigate the microstructural changes of the specimens. The resultant strengthening of the alloy sample could be mainly attributed to the interstitially dissolved nitrogen, the fraction of the tempered martensite, the fine grain and the presence of a smaller precipitate. The decrease in the tensile strength was mainly caused by the precipitation of vanadium-rich nitride.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.314-333
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• 2014

When analyzing default predictions in real estate companies, the number of non-defaulted cases always greatly exceeds the defaulted ones, which creates the two-class imbalance problem. This lowers the ability of prediction models to distinguish the default sample. In order to avoid this sample selection bias and to improve the prediction model, this paper applies a minority sample generation approach to create new minority samples. The logistic regression, support vector machine (SVM) classification, and neural network (NN) classification use an imbalanced dataset. They were used as benchmarks with a single prediction model that used a balanced dataset corrected by the minority samples generation approach. Instead of using prediction-oriented tests and the overall accuracy, the true positive rate (TPR), the true negative rate (TNR), G-mean, and F-score are used to measure the performance of default prediction models for imbalanced dataset. In this paper, we describe an empirical experiment that used a sampling of 14 default and 315 non-default listed real estate companies in China and report that most results using single prediction models with a balanced dataset generated better results than an imbalanced dataset.

• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.67-77
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• 1984

Going to the studies on parasite control carried out in the past. Infection rate among the rural population is contineously decreasing, however, it is still high in Korea. The most important reason for this high infectious rate is the use of manure as fertilizer. This study was aimed at finding the relationship between the infection rate and manure through analizing 83 samples of soil collected from Sa Am-Ri, Kangwon-do in June and July, 1983. The major findings of the study are as follows: 1. 60 cases out of the total sample were carry in at least one or more parasitic eggs, thus revealing 72.3% of positive rate. 2. A total number of 131 parasitic eggs were detected from total sample with an average of 1.6 eggs per 10 g of soil. 3. Asearid eggs more frequently appeared than other parasitic eggs occupying 68.7% or 1.2 eggs in average per 10g of soil. 4. There was revealed positive relationship between infectious rate and frequency of use of manure. (P > 0.05). 5. Infectious rate and average number of parasitic eggs detected were less in the fertilizer mixed with manure and ash than in the soil where only manure was used. (P > 0.05).

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.67-73
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• 2024

Purpose: Posttraumatic stress disorder (PTSD) is prevalent and is associated with protracted recovery and worse outcomes after injury. This study compared PTSD prevalence using the PTSD Checklist for DSM-5 (PCL-5) with the prevalence of PTSD risk using the Injured Trauma Survivor Screen (ITSS). Methods: Adult trauma patients at a level I trauma center were screened with the PCL-5 (sample 1) at follow-up visits or using the ITSS as inpatients (sample 2). Results: Sample 1 (n=285) had significantly fewer patients with gunshot wounds than sample 2 (n=45) (8.1% vs. 22.2%, P=0.003), nonsignificantly fewer patients with a fall from a height (17.2% vs. 28.9%, P=0.06), and similar numbers of patients with motor vehicle collision (40.7% vs. 37.8%, P=0.07). Screening was performed at a mean of 154 days following injury for sample 1 versus 7.1 days in sample 2. The mean age of the patients in sample 1 was 45.4 years, and the mean age of those in sample 2 was 46.1 years. The two samples had similar proportions of female patients (38.2% vs. 40.0%, P=0.80). The positive screening rate was 18.9% in sample 1 and 40.0% in sample 2 (P=0.001). For specific mechanisms, the positive rates were as follows: motor vehicle collisions, 17.2% in sample 1 and 17.6% in sample 2 (P>0.999); fall from height, 12.2% in sample 1 and 30.8% in sample 2 (P=0.20); and gunshot wounds, 39.1% in sample 1 and 80.0% in sample 2 (P=0.06). Conclusions: The ITSS was obtained earlier than PCL-5 and may identify PTSD in more orthopedic trauma patients. Differences in the frequency of PTSD may also be related to the screening tool itself, or underlying patient risk factors, such as mechanism of injury, or mental or social health.

• The Journal of Internal Korean Medicine
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• v.22 no.2
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• pp.145-160
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• 2001

Objectives : The purpose of this investigation is to evaluate the effect of Geupoongjibo-dan Extracts on Reversible Forebrain Ischemia in Mongolian Gerbils. Methods : The change rate of water content in cerebral tissues, the numercal change of the CA1 pyramidal neuron in the hippocampus, the change of delayed neuronal death(necrosis apoptosis) through light microscopy, the reactivity change of glycoprotein in neuronal membrane and the ultrastructural change of pyramidal neuron through electron microscopy caused by dalayed neuronal death were investigated. Results : 1. The change rate of water content in the normal group showed 78.90% on the third day, and 79.12% on the seventh day after an attack of ischemia. The rate in the control group showed 82.25% and 85.13%, respectively. The rate in the sample group showed a significant decrease: 81.72% and 83.66%. 2. Light microscopy revealed that the cells, continuous and systematic forms in the pyramidal cells of hippocampus, changed into discontinuous and unsystematic forms in the normal group when compared with the control group. The cells were less damaged in the sample group. 3. The mean of the numerical change of the CA1 pyramidal neurons in the hippocampus was 104 in the normal group. The mean of the control group was decreased to 27. The mean of the sample group was 44. 4. TUNEL staining examination reveals that the whole part of the hippocampus of the normal group had negative reactivity. As far as CA1 pyramidal neurons in the hippocampus, the control group had positive reactivity. The sample group was more positive than the control group. 5. Electron microscopy reveals that the ischemic injury of the control group had both necrotic and apoptotic morphology. The sample group was less necrotic, and more apoptotic morphology than the control group. 6. Lectin histochemisrical examination reveals that the normal group had positive reactivity to PNA and SBA in interneuron, and weak positive reactivity to WGA Con A LCA in intercelluar space. The reactivity to PNA and WGA decreased in the control group. The reactivity to PNA and WGA tended to increase in the sample group. Conclusions : The data shows that the effect of Geupoongjibo-dan Extracts on Reversible Forebrain Ischemia in MG is a significant result.

• Restorative Dentistry and Endodontics
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• v.49 no.1
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• pp.3.1-3.8
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• 2024

This article is a narrative review that discusses the recommended sample size requirements to design a pilot study to assess the reliability of a questionnaire. A list of various sample size tables that are based on the kappa agreement test, intra-class correlation test and Cronbach's alpha test has been compiled together. For all calculations, type I error (alpha) was set at a maximum value of 0.05, and power was set at a minimum value of 80.0%. For the kappa agreement test, intra-class correlation test, and Cronbach's alpha test, the recommended minimum sample size requirement based on the ideal effect sizes shall be at least 15, 22, and 24 subjects respectively. By making allowances for a non-response rate of 20.0%, a minimum sample size of 30 respondents will be sufficient to assess the reliability of the questionnaire. The clear guideline of minimum sample size requirement for the pilot study to assess the reliability of a questionnaire is discussed and this will ease researchers in preparation for the pilot study. This study provides justification for a minimum requirement of a sample size of 30 respondents specifically to test the reliability of a questionnaire.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.363-369
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• 2021

In this paper, We propose variable cut-off frequency and variable sample rate small-area multi-channel digital filter for telemetry system. Proposed digital filter reduced hardware area by implementing filter banks that can variably use cut-off frequency and sample rate without additional filter banks for an arbitrary cut ratio. In addition, We propose the architecture in which sample rate can variably be selected according to the number of filters that pass through the multiplexer control. By using time division multiplexing (TDM) supported by the finite impulse response (FIR) intellectual property (IP) of Quartus, the proposed digital filter can greatly reduce digital signal processing (DSP) blocks from 80 to 1 compared without TDM. Proposed digital filter calculated order and coefficients using Kaiser window function in Matlab, and implemented using very high speed integrated circuits hardware descryption language (VHDL). After applying to the telemetry system, we confirmed that the proposed digital filter was operating through the experimental results in the test environment.

• Journal of the Korean Statistical Society
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• v.23 no.2
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• pp.349-365
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• 1994

We develop in this paper the likelihood ratio test (LRT) for testing $H_1 : F_1 \preceq F_2$ against $H_2 - H_1$ where $H_2$ imposes no restriction on $F_1$ and $F_2$ and '$\preceq$' means failure rate ordering. Both one and two-sample problems will be considered. In the one-sample case, one of the two distributions is known, while we assume in the other case both are unknown. We derive the asymptotic null distribution of the LRT statistic which will be of chi-bar-square type. The main issue here is to determine the least favorable distribution which is stochastically largest within the class of null distributions.