• Title/Summary/Keyword: 사전확률

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Improved real-time power analysis attack using CPA and CNN

  • Kim, Ki-Hwan;Kim, HyunHo;Lee, Hoon Jae
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.1
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    • pp.43-50
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    • 2022
  • Correlation Power Analysis(CPA) is a sub-channel attack method that measures the detailed power consumption of attack target equipment equipped with cryptographic algorithms and guesses the secret key used in cryptographic algorithms with more than 90% probability. Since CPA performs analysis based on statistics, a large amount of data is necessarily required. Therefore, the CPA must measure power consumption for at least about 15 minutes for each attack. In this paper proposes a method of using a Convolutional Neural Network(CNN) capable of accumulating input data and predicting results to solve the data collection problem of CPA. By collecting and learning the power consumption of the target equipment in advance, entering any power consumption can immediately estimate the secret key, improving the computational speed and 96.7% of the secret key estimation accuracy.

A Study on Fraud Detection in the C2C Used Trade Market Using Doc2vec

  • Lim, Do Hyun;Ahn, Hyunchul
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.3
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    • pp.173-182
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    • 2022
  • In this paper, we propose a machine learning model that can prevent fraudulent transactions in advance and interpret them using the XAI approach. For the experiment, we collected a real data set of 12,258 mobile phone sales posts from Joonggonara, a major domestic online C2C resale trading platform. Characteristics of the text corresponding to the post body were extracted using Doc2vec, dimensionality was reduced through PCA, and various derived variables were created based on previous research. To mitigate the data imbalance problem in the preprocessing stage, a complex sampling method that combines oversampling and undersampling was applied. Then, various machine learning models were built to detect fraudulent postings. As a result of the analysis, LightGBM showed the best performance compared to other machine learning models. And as a result of SHAP, if the price is unreasonably low compared to the market price and if there is no indication of the transaction area, there was a high probability that it was a fraudulent post. Also, high price, no safe transaction, the more the courier transaction, and the higher the ratio of 0 in the price also led to fraud.

Development of a Habitat Suitability Index for Vulpes vulpes (여우(Vulpes vulpes)의 서식지 적합성 지수(HSI) 모델 개발)

  • Ou, Yeokyung;Lee, Sangdon
    • Journal of Environmental Impact Assessment
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    • v.31 no.4
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    • pp.265-270
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    • 2022
  • With the implementation of the fox restoration project, the number of foxes released into nature are increasing; therefore, in the future, foxes will be dispersed to other areas and will appear in human habitats. In this study, the habitat suitability index (HSI) of foxes was developed to predict and prepare for the effects. After extracting major environmental variables through literature research and GIS analysis, 5 suitability indices (SIs) were constructed. The forest physiognomy, slope, aspect, distance from water source, and distance from road are the main variables, and the arithmetic average value by giving twice the weight to the forest physiognomy is the HSI result. As a result of comparing with the data from the Natural Environment Survey, it is found that the fox coordinates have an average HSI value of 0.64, and the probability of appearance is high when it is 0.53 or higher. Using the results of this study, it is expected to be able to predict the distribution of foxes in advance, to use them as basic data for future restoration plans, or to identify the distribution of the species and the reduction plan in future environmental impact assessments.

A State-space Production Assessment Model with a Joint Prior Based on Population Resilience: Illustration with the Common Squid Todarodes pacificus Stock (자원복원력 개념을 적용한 사전확률분포 및 상태공간 잉여생산 평가모델: 살오징어(Todarodes pacificus) 개체군 자원평가)

  • Gim, Jinwoo;Hyun, Saang-Yoon;Yoon, Sang Chul
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.2
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    • pp.183-188
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    • 2022
  • It is a difficult task to estimate parameters in even a simple stock assessment model such as a surplus production model, using only data about temporal catch-per-unit-effort (CPUE) (or survey index) and fishery yields. Such difficulty is exacerbated when time-varying parameters are treated as random effects (aka state variables). To overcome the difficulty, previous studies incorporated somewhat subjective assumptions (e.g., B1=K) or informative priors of parameters. A key is how to build an objective joint prior of parameters, reducing subjectivity. Given the limited data on temporal CPUEs and fishery yields from 1999-2020 for common squid Todarodes pacificus, we built a joint prior of only two parameters, intrinsic growth rate (r) and carrying capacity (K), based on the resilience level of the population (Froese et al., 2017), and used a Bayesian state-space production assessment model. We used template model builder (TMB), a R package for implementing the assessment model, and estimating all parameters in the model. The predicted annual biomass was in the range of 0.76×106 to 4.06×106 MT, the estimated MSY was 0.13×106 MT, the estimated r was 0.24, and the estimated K was 2.10×106 MT.

Edge Caching Strategy with User Mobility in Heterogeneous Cellular Network Environments (이종 셀룰러 네트워크 환경에서 사용자 이동성을 고려한 엣지 캐싱 기법)

  • Choi, Yoonjeong;Lim, Yujin
    • KIPS Transactions on Computer and Communication Systems
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    • v.11 no.2
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    • pp.43-50
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    • 2022
  • As the use of mobile data increases, the proportion of video content is increasing steeply. In order to solve problems that arise when mobile users receive data from geographically remote cloud servers, methods of caching data in advance to edge servers geographically close to the users are attracting lots of attention. In this paper, we present a caching policy that stores data on Small Cell Base Station(SBS) to effectively provide content files to mobile users by applying a delayed offloading scheme in a cellular network. The goal of the proposed policy is to minimize the size of data transmitted from Macro Base Station(MBS) because the delayed offloading scheme requires more cost than when downloaded from MBS than from SBS. The caching policy is proposed to determine the size of content file and which content file to be cached to SBS using the probability of mobile users' paths and the popularity of content files, and to replace content files in consideration of the overlapping coverage of SBS. In addition, through performance evaluation, it has been proven that the proposed policy reduces the size of data downloaded from MBS compared to other algorithms.

The Influence of Robot Education Using Magnetic Force on the Computational Thinking (자력을 활용한 로봇 교육이 컴퓨팅 사고력에 미치는 영향)

  • Lee, Jaeho;Kim, Hakmin
    • Journal of Creative Information Culture
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    • v.5 no.3
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    • pp.275-283
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    • 2019
  • The fourth industrial revolution is emerging as the talk of the times. The industrial structure is changing greatly from the past, as well as the social scene, changing our daily lives. Especially, the importance of the software sector is growing. For students who have to live in this future society, computational thinking is a key capability. In order to achieve this goal, this study was carried out in the following steps. First, we organized a SW education convergence program based on life-oriented aspects. Second, the configured program was applied to the site to verify the effectiveness of computational thinking. The results of this study show that the experimental group has 32 points better than the pre-test, and the comparative group has about 2 points better. The statistical significance probability was a significant difference of .028. The results of this study may be used as a reference for the training of SW convergence education and future talent in the future.

Assessment of Contamination of Harbor Dredged Materials for Beneficial Use (항만준설토사 유효활용을 위한 오염도 평가)

  • Yoon, Gil-Lim;Jeong, Woo-Seob
    • Journal of the Korean Geotechnical Society
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    • v.24 no.5
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    • pp.15-25
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    • 2008
  • Contamination level assessment of harbor dredged materials is carried out for beneficial use, which generated annually due to port construction and maintenance of harbor channel. The basic purpose of environmental risk assessment was a scientific approach to susceptibility of hazard risk to human's health from different dredged materials. And this paper proposes a guideline of safely beneficial use of dredged materials at both industrial area and residental area, generated from major port execution throughout a sound investigation of their contamination levels. Newly proposed guidelines were in general higher levels compared to both current guidelines of treatment and use of dredged materials and soil environment protection levels. Finally, environmental assessment results of dredged material contamination generated in major ports of Korea for beneficial use based on pre-assessment environmental levels show that some port's dredged materials contain heavy metals such as Cd, As, Cr and Zn, more than base levels which requires more precise contamination investigation. Others were found to be very appropriate for beneficial use.

비대면 창업 멘토링 방식이 멘티의 만족도에 미치는 영향 분석

  • Hwang, Bo-Yun
    • 한국벤처창업학회:학술대회논문집
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    • 2021.04a
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    • pp.79-83
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    • 2021
  • 2020년 2월 중순 이루 코로나 바이러스 2019(Covid-19)로 인하여 정부의 기술창업기업 지원 방식도 전반적으로 기존의 대면 방식에서 비대면 방식으로 전환하여 현재까지 대부분 진행되어 오고 있다. 창업기업에 대한 멘토링은 특히 멘티인 창업자와 멘토가 기존에 알고 있는 관계가 아닌 대부분 처음 만나는 관계의 확률이 높음에 따라 사전에 상호간에 라포(Rapport)가 형성되지 않은 상태에서 멘토링이 이루어진다. 이로 인해 Rapport가 형성이 안된 상태에서는 서로 호감을 느끼거나, 나아가 공감대 형성, 그리고 터놓고 이야기 하여, 서로 간의 대화가 충분히 감정적으로나 이성적으로 이해하기가 어려운 경우가 대부분이다. 이러한 경우에는 충분한 멘토링이 어려울 것으로 예상할 수 있다. 따라서 본 연구는 창업 멘토링의 특수성을 감안해 볼 때 정부 기술창업지원 방식 중 기업의 성과를 높이기 위한 멘토링 과정에서 대면 또는 비대면 방식의 방법 차이가 멘토링 만족도에 영향을 주는 것을 그 목적으로 한다. 본 연구는 창업 기업의 성과를 높이기 위한 중소벤처기업부의 도약패키지 사업 중 2019년과 2020년의 제품 아카데미 사업에 참여한 283명을 대면 방식이었던 2019년 211명과 비대면 방식이었던 2020년 72명의 창업 기업 멘티들의 학습 과정에서 발생하는 배운 내용을 실천하고자 하는 학습 전이 효과 경로에 차이가 발생하는 지에 대하여 분석하였다. 자기 기입 설문 방식으로 인해 발생할 수 있는 동일방법편의를 해결하고자 구조화된 설문지 구성할 때부터 응답자의 일관성 동기를 줄이려고 하였고, 통계분석 단계에서도 다수이 방법으로 측정하는 일반 CFA 모형을 활용하였다. 실증 분석결과 비대면 방식의 창업 멘토링 방식을 학습 전이 효과 경로 결과에 있어서 조절효과가 있음을 유의한 통계적 결과고 확인하고, 사후 검증을 통해 볼 때 등분산 가정이 되지 않은 상황에서 차이가 있음을 통계적으로 유의하게 나타났다.

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The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.

A Characterization of Oil Sand Reservoir and Selections of Optimal SAGD Locations Based on Stochastic Geostatistical Predictions (지구통계 기법을 이용한 오일샌드 저류층 해석 및 스팀주입중력법을 이용한 비투멘 회수 적지 선정 사전 연구)

  • Jeong, Jina;Park, Eungyu
    • Economic and Environmental Geology
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    • v.46 no.4
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    • pp.313-327
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    • 2013
  • In the study, three-dimensional geostatistical simulations on McMurray Formation which is the largest oil sand reservoir in Athabasca area, Canada were performed, and the optimal site for steam assisted gravity drainage (SAGD) was selected based on the predictions. In the selection, the factors related to the vertical extendibility of steam chamber were considered as the criteria for an optimal site. For the predictions, 110 borehole data acquired from the study area were analyzed in the Markovian transition probability (TP) framework and three-dimensional distributions of the composing media were predicted stochastically through an existing TP based geostatistical model. The potential of a specific medium at a position within the prediction domain was estimated from the ensemble probability based on the multiple realizations. From the ensemble map, the cumulative thickness of the permeable media (i.e. Breccia and Sand) was analyzed and the locations with the highest potential for SAGD applications were delineated. As a supportive criterion for an optimal SAGD site, mean vertical extension of a unit permeable media was also delineated through transition rate based computations. The mean vertical extension of a permeable media show rough agreement with the cumulative thickness in their general distribution. However, the distributions show distinctive disagreement at a few locations where the cumulative thickness was higher due to highly alternating juxtaposition of the permeable and the less permeable media. This observation implies that the cumulative thickness alone may not be a sufficient criterion for an optimal SAGD site and the mean vertical extension of the permeable media needs to be jointly considered for the sound selections.