• Title/Summary/Keyword: 잠재변수 점수

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Bi-LSTM VAE based Intrusion Detection System for In-Vehicle CAN (Bi-LSTM VAE 기반 차량 CAN 침입 탐지 시스템)

  • Kim, Yong-Su;Kang, Hyo-Eun;Kim, Ho-Won
    • Proceedings of the Korea Information Processing Society Conference
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    • 2022.05a
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    • pp.531-534
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    • 2022
  • 승차 공유, 카풀, 렌터카의 이용률이 증가하면서 많은 사용자가 동일한 차량에 로컬 액세스 할 수 있는 시나리오가 더욱 보편화됨에 따라 차량 네트워크에 대한 공격 가능성이 커지고 있다. 차량용 CAN Bus Network에 대한 DoS(Denial of Service), Fuzzy Attack 및 Replay Attack과 같은 공격은 일부 ECU(Electronic Controller Unit) 비활성 및 작동 불능 상태를 유발한다. 에어백, 제동 시스템과 같은 필수 시스템이 작동 불가 상태가 되어 운전자에게 치명적인 결과를 초래할 수 있다. 차량 네트워크 침입 탐지를 위하여 많은 연구가 진행되고 있으나, 기존 화이트리스트를 이용한 탐지 방법은 새로운 유형의 공격이 발생하거나 희소성이 높은 공격일 때 탐지하기 어렵다. 본 논문에서는 인공신경망 기반의 CAN 버스 네트워크 침입 탐지 기법을 제안한다. 제안하는 침입 탐지 기법은 2단계로 나누어 진다. 1단계에서 정상 패킷 분포를 학습한 VAE 모형이 이상 탐지를 수행한다. 이상 패킷으로 판정될 경우, 2단계에서 인코더로부터 추출된 잠재변수와 VAE의 재구성 오차를 이용하여 공격 유형을 분류한다. 분류 결과의 신뢰점수(Confidence score)가 임계치보다 낮을 경우 학습하지 않은 공격으로 판단한다. 본 연구 결과물은 정보보호 연구·개발 데이터 첼린지 2019 대회의 차량 이상징후 탐지 트랙에서 제공하는 정상 및 3종의 차량 공격시도 패킷 데이터를 대상으로 성능을 평가하였다. 실험을 통해 자동차 제조사의 규칙이나 정책을 사전에 정의하지 않더라도 낮은 오탐율로 비정상 패킷을 탐지해 낼 수 있음을 확인할 수 있다.

An Analysis of Non-linear Effects of Impact Factors on Housing Price (주택매매가격 영향요인의 비선형적 효과 분석)

  • Chang, Youngjae
    • Journal of the Korean Data Analysis Society
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    • v.20 no.6
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    • pp.2953-2966
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    • 2018
  • Housing prices are closely related to various variables that indicate macroeconomic conditions. In this paper, empirical analysis based on data is performed referring to previous studies. Focusing on the policy interest rate among the factors affecting the housing price, the non-linear impulse responses of other variables to the interest rate shock are analyzed. Using the random forest algorithm, the variable importance scores of the macroeconomic variables presented in the previous studies are calculated. After selecting the variables through this process, the impulse responses are calculated using a model that can capture non-linearity. According to the model, the responses of housing prices to the policy rate is only significant when the rate is raised. Especially, the impulse response is amplified when the shock increases due to the non-linear characteristics that can not be captured by the traditional VAR methodology. The analysis results suggest that the interest rate as a policy instrument should be approached from a more cautious perspective.

A Study on the Internet Game and Smartphone Usage of the Senior Elementary School Students (초등학교 고학년의 인터넷 게임 및 스마트폰 이용실태에 관한 연구)

  • Lee, In-Suk;Lee, Mi-Hyoung;Kim, Hee-Kyung;Park, Jeong-Sook;Son, Ji-Hye
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.421-432
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    • 2020
  • This study was designed to determine the Internet game and smartphone usage status of senior elementary school students. Data were collected from 6 October 2018 to 30 September 2019, and 1618 subjects were analyzed using SPSS 18.0. As a result of the study, the I-GUESS rating was 6.1% in the high-risk group, and, the S-scale ratios were 10.1% for the potential-risk group and 0.8% for the high-risk group. Physical problems related to Internet games and using smartphones were experienced by 36.0% of the students, with eye fatigue being the highest at 20.4%. Emotional problems were found in 18.5% of the students, with anger being the highest at 6.8%. Social problems were experienced by 21.8% of the students, conflicts with parents being the highest at 10.3%. As a result of surveying the main content based on S-scale and I-GUESS, it was found that the higher the S-scale ratio and the I-GUESS rating, the more broadcast content was used. The correlation between I-GUESS rating and S-scale ratio showed that the higher the I-GUESS rating, the higher the S-scale ratio, and the higher the S-scale ratio, the higher the I-GUESS rating. Future research is necessary to develop an intervention program for elementary school students from a preventive perspective.

A Study on Road Characteristic Classification using Exploratory Factor Analysis (탐색적 요인분석을 이용한 도로특성분류에 관한 연구)

  • Cho, Jun-Han;Kim, Seong-Ho;Rho, Jeong-Hyun
    • Journal of Korean Society of Transportation
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    • v.26 no.3
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    • pp.53-66
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    • 2008
  • This research is to the establishment of a conceptual framework that supports road characteristic classification from a new point of view in order to complement of the existing road functional classification and examine of traffic pattern. The road characteristic classification(RCC) is expected to use important performance criteria that produced a policy guidelines for transportation planning and operational management. For this study, the traffic data used the permanent traffic counters(PTCs) located within the national highway between 2002 and 2006. The research has described for a systematic review and assessment of how exploratory factor analysis should be applied from 12 explanatory variables. The optimal number of components and clusters are determined by interpretation of the factor analysis results. As a result, the scenario including all 12 explanatory variables is better than other scenarios. The four components is produced the optimal number of factors. This research made contributions to the understanding of the exploratory factor analysis for the road characteristic classification, further applying the objective input data for various analysis method, such as cluster analysis, regression analysis and discriminant analysis.

The Association Between Neck Pain/Disability and Upper Limb Disability in Patients with Non-Specific Neck Pain (비특이성 경부통 환자의 경부통/경부기능장애와 상지 기능장애 간의 상관성)

  • Jang, Hyun-Jeon;Kim, Suhn-Yeop;Jeon, Jae-Guk;Shin, Eui-Ju
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.6
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    • pp.2862-2868
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    • 2013
  • The purpose of this study was to investigate the relationship between neck pain and upper limb disability in patients with non-specific neck pain (n=132) recruited from physiotherapy departments in the Korea. Baseline neck pain/disability was measured using the Northwick Park Neck Pain Questionnaire (NPQ) and upper limb disability was measured using the Disabilities of Arm, Shoulder, Hand questionnaire (DASH). A range of baseline psychosocial variables were measured as potential confounding variables. Pairwise analysis revealed a positive correlation between NPQ score and DASH score (Pearsons' r=0.628, p<0.05). This study provides preliminary evidence that patients with severe neck pain/disability also report severe upper limb disability. The presence of severe neck pain or low pain self efficacy and high fear-avoidence beliefs questionnaire should clinicians towards a careful examination of upper limb function in patients presenting with neck pain. Our data suggest the upper limb disability may need to be addressed as part of the neck management process.

A study on tourist satisfaction of the Daegu City Tour using a structural equation model (구조방정식모형을 이용한 대구시티투어 관광객의 만족도 연구)

  • Song, Mi-Jung;Lee, Ji-Yeon
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.6
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    • pp.1075-1087
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    • 2011
  • We analyze the tourist satisfaction of the Daegu City Tour which plays a big role in the local tourism boosting through '2011 Visit Daegu Year'. To analyze a causal relation among factors, we proposed a structural equation model consisting of four latent variables of the tour: motivation, expectation, satisfaction, and future behaviors. Using data from the actual tourists of the Daegu City Tour, we found out that tourists' motivation before the tour does not affect tourists' satisfaction after the tour. However those who have higher motivation have positive future behavior and those who have the higher expectation are more satisfied with the tour. Meanwhile, the expectation before the tour does not lead the future behavior but the satisfaction after the tour influences the positive future behavior.

Relationships between Mental Health, Depression Level, and Internet Addiction among High School Students in Rural Communities (농촌지역 고등학생의 정신건강, 우울정도 및 인터넷 중독과의 관계)

  • Oh, Hyun-Ei;Sim, Mi-Jung;Oh, Hyo-Sook
    • Journal of agricultural medicine and community health
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    • v.35 no.2
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    • pp.124-133
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    • 2010
  • Objectives: This study is to offer basic data to understand the relationships between mental health, level of depression, and internet addiction of high school students in farming communities for developing a mental health management program for adolescents. Methods: The survey was carried out on a convenience sample of 299 high school students in farming communities during May of 2008. Data analysis procedure included $X^2$-test, t-test, Pearson correlation among Adolescent Mental Health & Problem-behavior Screening Questionnaire (AMPQ), Children's Depression Inventory (CDI), and Scales of Internet addiction (K-scales). Results: First, the level of mental health according to the AMPQ for subjects from this study showed problematic behavior was lower when compared to other researches. There were statistically significant differences according to the school type for externalization problems and overall problematic behavior. Based on gender, it was even more problematic for male students in regards to externalization problems. Secondly, the level of depression was relatively low : 5.1% for potential risk and 0.3% for high risk. Thirdly, a total of 96.9% were considered normal for Internet addition levels. 1.7% for potential risk, 1.4% for high risk; however, there was no statistically significant difference between each variable. Fourthly, there was a strong relationship between subjects AMPQ, level of depression and Internet addiction. As depression worsens, Internet addiction also becomes stronger. Conclusion: There is a need for awareness of the mental health of adolescents and precautionary measures, the development of a program for early treatment, adequate management, and decisions on the direction of treatment.

Anomaly Detection for User Action with Generative Adversarial Networks (적대적 생성 모델을 활용한 사용자 행위 이상 탐지 방법)

  • Choi, Nam woong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.43-62
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    • 2019
  • At one time, the anomaly detection sector dominated the method of determining whether there was an abnormality based on the statistics derived from specific data. This methodology was possible because the dimension of the data was simple in the past, so the classical statistical method could work effectively. However, as the characteristics of data have changed complexly in the era of big data, it has become more difficult to accurately analyze and predict the data that occurs throughout the industry in the conventional way. Therefore, SVM and Decision Tree based supervised learning algorithms were used. However, there is peculiarity that supervised learning based model can only accurately predict the test data, when the number of classes is equal to the number of normal classes and most of the data generated in the industry has unbalanced data class. Therefore, the predicted results are not always valid when supervised learning model is applied. In order to overcome these drawbacks, many studies now use the unsupervised learning-based model that is not influenced by class distribution, such as autoencoder or generative adversarial networks. In this paper, we propose a method to detect anomalies using generative adversarial networks. AnoGAN, introduced in the study of Thomas et al (2017), is a classification model that performs abnormal detection of medical images. It was composed of a Convolution Neural Net and was used in the field of detection. On the other hand, sequencing data abnormality detection using generative adversarial network is a lack of research papers compared to image data. Of course, in Li et al (2018), a study by Li et al (LSTM), a type of recurrent neural network, has proposed a model to classify the abnormities of numerical sequence data, but it has not been used for categorical sequence data, as well as feature matching method applied by salans et al.(2016). So it suggests that there are a number of studies to be tried on in the ideal classification of sequence data through a generative adversarial Network. In order to learn the sequence data, the structure of the generative adversarial networks is composed of LSTM, and the 2 stacked-LSTM of the generator is composed of 32-dim hidden unit layers and 64-dim hidden unit layers. The LSTM of the discriminator consists of 64-dim hidden unit layer were used. In the process of deriving abnormal scores from existing paper of Anomaly Detection for Sequence data, entropy values of probability of actual data are used in the process of deriving abnormal scores. but in this paper, as mentioned earlier, abnormal scores have been derived by using feature matching techniques. In addition, the process of optimizing latent variables was designed with LSTM to improve model performance. The modified form of generative adversarial model was more accurate in all experiments than the autoencoder in terms of precision and was approximately 7% higher in accuracy. In terms of Robustness, Generative adversarial networks also performed better than autoencoder. Because generative adversarial networks can learn data distribution from real categorical sequence data, Unaffected by a single normal data. But autoencoder is not. Result of Robustness test showed that he accuracy of the autocoder was 92%, the accuracy of the hostile neural network was 96%, and in terms of sensitivity, the autocoder was 40% and the hostile neural network was 51%. In this paper, experiments have also been conducted to show how much performance changes due to differences in the optimization structure of potential variables. As a result, the level of 1% was improved in terms of sensitivity. These results suggest that it presented a new perspective on optimizing latent variable that were relatively insignificant.

Conjoint analysis by merging attributes (속성 병합에 의한 컨조인트 분석)

  • Lim, Yong B.;Park, Gahee;Chung, Jong Hee
    • Journal of Korean Society for Quality Management
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    • v.45 no.1
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    • pp.55-64
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    • 2017
  • Purpose: A large number of attributes with mixed levels are often considered in the conjoint analysis. The respondents may have difficulty with scoring their preferences accurately because of many attribute items involved in each survey question. We research on the technique for reducing the number of attribute items. Methods: In order to reduce the number of attribute items in a survey question, we make a new attribute by merging two original attributes. A 'No question' option is also included as a new level in a merged attribute. Results: We propose BIB $6^4$ design in the case where we have four attributes with 2 levels and 3 levels, respectively and then analyze all the respondents survey data generated by the repeated simulation study in order to compare various model selection methods. Conclusion: How to reduce the number of attribute items is proposed and how to design and analyze the survey data are illustrated.

Classification of Recreation Forests through Cluster Analysis (군집분석을 통한 전국 자연휴양림 유형분류)

  • Lee, Kee-Cheol;Kang, Kee-Rae
    • Journal of the Korean Institute of Landscape Architecture
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    • v.37 no.1
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    • pp.9-17
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    • 2009
  • Twenty years have passed since the adoption of natural recreation forests and each forest has its own characteristics. However, there is hardly any classification among the natural recreation forests. The purpose of this study is to classify the forests by considering the supplier's perspective as well as the user's perspective in order to provide fundamental materials for the operation of the natural recreation forests. A factor analysis was conducted to identify the common characteristics of the selected twelve variables by pre-selection and survey of experts. K-means cluster analysis was conducted among those factors to classify the natural recreation forests in Korea. Four factors were drawn after the factor analysis and the factors were named according to the variables and sizes as 'The use performance and visiting condition factor', 'Education and settlement factor', 'Internal activation factor' and 'Potential factor' In addition, the cluster analysis of an $85{\times}4$ matrix was conducted for the points of the drawn factors and the final classification consists of five groups. The results of this study may contribute to providing fundamental materials for the operation and management of natural recreation forests. Also, it may act as a reference when investigating the natural recreation forests of Korea. Proposing the classification natural recreation forests could be helpful in selecting the proper recreation forest in the future. Based on the established model, fundamental materials could be provided to improve the profitability of the natural recreation forests by effectively expanding the number of tourists, creating new natural recreation forests and proper maintenance and management.