• Title/Summary/Keyword: Conditional Value

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Understanding Customer Values by Analyzing the Contents of Online Hotel Reviews (온라인 호텔이용후기의 질적 내용분석에 의한 고객가치 연구)

  • Lee, Jung-Hun
    • The Journal of the Korea Contents Association
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    • v.13 no.10
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    • pp.533-546
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    • 2013
  • This study analyzed the contents of online hotel reviews of Benikea hotels. The results were as follows: First, the outstanding customer value were functional value, emotional value, price/value for money and epistemic value, conditional value are next. Social value was not found. Functional value was provoked by the functions of hotel room, room amenities, room view, room cleaness, restaurant service, and hotel staff friendliness as human services. Emotional value was the emotional response to the qualities of hotel's functions. Price/value for money was a perceived value of hotel user by the comparison of what to invest with what to receive. From the results, it can be proposed that hotel should maintain the basic qualities of core functions of hotel.

A Study of Anomaly Detection for ICT Infrastructure using Conditional Multimodal Autoencoder (ICT 인프라 이상탐지를 위한 조건부 멀티모달 오토인코더에 관한 연구)

  • Shin, Byungjin;Lee, Jonghoon;Han, Sangjin;Park, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.57-73
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    • 2021
  • Maintenance and prevention of failure through anomaly detection of ICT infrastructure is becoming important. System monitoring data is multidimensional time series data. When we deal with multidimensional time series data, we have difficulty in considering both characteristics of multidimensional data and characteristics of time series data. When dealing with multidimensional data, correlation between variables should be considered. Existing methods such as probability and linear base, distance base, etc. are degraded due to limitations called the curse of dimensions. In addition, time series data is preprocessed by applying sliding window technique and time series decomposition for self-correlation analysis. These techniques are the cause of increasing the dimension of data, so it is necessary to supplement them. The anomaly detection field is an old research field, and statistical methods and regression analysis were used in the early days. Currently, there are active studies to apply machine learning and artificial neural network technology to this field. Statistically based methods are difficult to apply when data is non-homogeneous, and do not detect local outliers well. The regression analysis method compares the predictive value and the actual value after learning the regression formula based on the parametric statistics and it detects abnormality. Anomaly detection using regression analysis has the disadvantage that the performance is lowered when the model is not solid and the noise or outliers of the data are included. There is a restriction that learning data with noise or outliers should be used. The autoencoder using artificial neural networks is learned to output as similar as possible to input data. It has many advantages compared to existing probability and linear model, cluster analysis, and map learning. It can be applied to data that does not satisfy probability distribution or linear assumption. In addition, it is possible to learn non-mapping without label data for teaching. However, there is a limitation of local outlier identification of multidimensional data in anomaly detection, and there is a problem that the dimension of data is greatly increased due to the characteristics of time series data. In this study, we propose a CMAE (Conditional Multimodal Autoencoder) that enhances the performance of anomaly detection by considering local outliers and time series characteristics. First, we applied Multimodal Autoencoder (MAE) to improve the limitations of local outlier identification of multidimensional data. Multimodals are commonly used to learn different types of inputs, such as voice and image. The different modal shares the bottleneck effect of Autoencoder and it learns correlation. In addition, CAE (Conditional Autoencoder) was used to learn the characteristics of time series data effectively without increasing the dimension of data. In general, conditional input mainly uses category variables, but in this study, time was used as a condition to learn periodicity. The CMAE model proposed in this paper was verified by comparing with the Unimodal Autoencoder (UAE) and Multi-modal Autoencoder (MAE). The restoration performance of Autoencoder for 41 variables was confirmed in the proposed model and the comparison model. The restoration performance is different by variables, and the restoration is normally well operated because the loss value is small for Memory, Disk, and Network modals in all three Autoencoder models. The process modal did not show a significant difference in all three models, and the CPU modal showed excellent performance in CMAE. ROC curve was prepared for the evaluation of anomaly detection performance in the proposed model and the comparison model, and AUC, accuracy, precision, recall, and F1-score were compared. In all indicators, the performance was shown in the order of CMAE, MAE, and AE. Especially, the reproduction rate was 0.9828 for CMAE, which can be confirmed to detect almost most of the abnormalities. The accuracy of the model was also improved and 87.12%, and the F1-score was 0.8883, which is considered to be suitable for anomaly detection. In practical aspect, the proposed model has an additional advantage in addition to performance improvement. The use of techniques such as time series decomposition and sliding windows has the disadvantage of managing unnecessary procedures; and their dimensional increase can cause a decrease in the computational speed in inference.The proposed model has characteristics that are easy to apply to practical tasks such as inference speed and model management.

A Study on the Scale Development of Clothing Consumption Value for Male Consumers -Focused on the Purchase Behavior in Fashion Multi-brand Store and Tailor Shop- (남성 소비자의 의복 소비가치 척도 개발 연구 -의류편집매장, 맞춤정장매장 구매행동을 중심으로-)

  • Kim, Tae Youn;Lee, Yoon-Jung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.6
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    • pp.885-898
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    • 2015
  • This study develops scales to measure clothing consumption values for Korean male consumers. This study conducted qualitative and quantitative research to explore a new clothing consumption value among males as well as investigate empirically the measurement of clothing consumption values. In-depth interviews and focus group interviews were collected for qualitative research on 20 Korean men in their 20s-40s who had experience with 2 types of stores in Korean men's fashion. An analysis of qualitative data based on grounded theory approaches identified 6 factors and 15 items. For the empirical research, the questionnaire which consist of 9 factors and 46 items were developed by the results of grounded theory approaches and prior studies. Final measurement scales were based on 651 data used in exploratory factor analysis (EFA) and a confirmatory factor analysis (CFA). All subjects were in their 20s-40s. The result from CFA suggested 4 factors and 18 items with showing acceptable construct validity and discriminant validity. Therefore, this study confirmed that clothing consumption value for Korean male consumer consist of ostentatious and brand value, epistemic and possession value, conditional value, and reasonable value. These constructs will provide critical insight in understanding and segmenting Korean male consumers.

Non-stationary Frequency Analysis with Climate Variability using Conditional Generalized Extreme Value Distribution (기후변동을 고려한 조건부 GEV 분포를 이용한 비정상성 빈도분석)

  • Kim, Byung-Sik;Lee, Jung-Ki;Kim, Hung-Soo;Lee, Jin-Won
    • Journal of Wetlands Research
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    • v.13 no.3
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    • pp.499-514
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    • 2011
  • An underlying assumption of traditional hydrologic frequency analysis is that climate, and hence the frequency of hydrologic events, is stationary, or unchanging over time. Under stationary conditions, the distribution of the variable of interest is invariant to temporal translation. Water resources infrastructure planning and design, such as dams, levees, canals, bridges, and culverts, relies on an understanding of past conditions and projection of future conditions. But, Water managers have always known our world is inherently non-stationary, and they routinely deal with this in management and planning. The aim of this paper is to give a brief introduction to non-stationary extreme value analysis methods. In this paper, a non-stationary hydrologic frequency analysis approach is introduced in order to determine probability rainfall consider changing climate. The non-stationary statistical approach is based on the conditional Generalized Extreme Value(GEV) distribution and Maximum Likelihood parameter estimation. This method are applied to the annual maximum 24 hours-rainfall. The results show that the non-stationary GEV approach is suitable for determining probability rainfall for changing climate, sucha sa trend, Moreover, Non-stationary frequency analyzed using SOI(Southern Oscillation Index) of ENSO(El Nino Southern Oscillation).

Early diagnosis of jaw osteomyelitis by easy digitalized panoramic analysis

  • Park, Moo Soung;Eo, Mi Young;Myoung, Hoon;Kim, Soung Min;Lee, Jong Ho
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.41
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    • pp.6.1-6.10
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    • 2019
  • Background: Osteomyelitis is an intraosseous inflammatory disease characterized by progressive inflammatory osteoclasia and ossification. The use of quantitative analysis to assist interpretation of osteomyelitis is increasingly being considered. The objective of this study was to perform early diagnosis of osteomyelitis on digital panoramic radiographs using basic functions provided by picture archiving and communication system (PACS), a program used to show radiographic images. Methods: This study targeted a total of 95 patients whose symptoms were confirmed as osteomyelitis under clinical, radiologic, pathological diagnosis over 11 years from 2008 to 2017. Five categorized patients were osteoradionecrosis, bisphosphonate-related osteonecrosis of jaw (BRONJ, suppurative and sclerosing type), and bacterial osteomyelitis (suppurative and sclerosing type), and the control group was 117 randomly sampled. The photographic density in a certain area of the digital panoramic radiograph was determined and compared using the "measure area rectangle," one of the basic PACS functions in INFINITT PACS® (INFINITT Healthcare, Seoul, South Korea). A conditional inference tree, one type of decision making tree, was generated with the program R for statistical analysis with SPSS®. Results: In the conditional inference tree generated from the obtained data, cases where the difference in average value exceeded 54.49 and the difference in minimum value was less than 54.49 and greater than 12.81 and the difference in minimum value exceeded 39 were considered suspicious of osteomyelitis. From these results, the disease could be correctly classified with a probability of 88.1%. There was no difference in photographic density value of BRONJ and bacterial osteomyelitis; therefore, it was not possible to classify BRONJ and bacterial osteomyelitis by quantitative analysis of panoramic radiographs based on existing research. Conclusions: This study demonstrates that it is feasible to measure photographic density using a basic function in PACS and apply the data to assist in the diagnosis of osteomyelitis.

Developing a Bayesian Network Model for Real-time Project Risk Management (실시간 프로젝트 위험관리를 위한 베이지안 네트워크 모형의 개발)

  • Kim, Jee-Young;Ahn, Sun-Eung
    • IE interfaces
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    • v.24 no.2
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    • pp.119-127
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    • 2011
  • Most companies have been increasing temporary work projects to maximize the usage of their resources. They also have been developing the effective techniques for analyzing and managing the state of the projects. In order to monitor the state of a project in real-time and predict the project's future state more accurately, this paper suggests the Bayesian Network (BN) as a tool for discovering the causes of project risk and presenting the failure probability of the project. The proposed BN modeling method with consideration of the Earned Value Management (EVM) method shows how to induce the predictive and conditional probability of the risk occurrence in the future. The advantages of the suggested model are (1) that the cause of a project risk can be easily figured out via the BN, (2) that the future value of the project can be sufficiently increased by updating relevant components of the project, and (3) that more credible prediction can be made in the similar and future situation by using the data obtained in current analysis. A numerical example is also given.

Three-dimensional geostatistical modeling of subsurface stratification and SPT-N Value at dam site in South Korea

  • Mingi Kim;Choong-Ki Chung;Joung-Woo Han;Han-Saem Kim
    • Geomechanics and Engineering
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    • v.34 no.1
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    • pp.29-41
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    • 2023
  • The 3D geospatial modeling of geotechnical information can aid in understanding the geotechnical characteristic values of the continuous subsurface at construction sites. In this study, a geostatistical optimization model for the three-dimensional (3D) mapping of subsurface stratification and the SPT-N value based on a trial-and-error rule was developed and applied to a dam emergency spillway site in South Korea. Geospatial database development for a geotechnical investigation, reconstitution of the target grid volume, and detection of outliers in the borehole dataset were implemented prior to the 3D modeling. For the site-specific subsurface stratification of the engineering geo-layer, we developed an integration method for the borehole and geophysical survey datasets based on the geostatistical optimization procedure of ordinary kriging and sequential Gaussian simulation (SGS) by comparing their cross-validation-based prediction residuals. We also developed an optimization technique based on SGS for estimating the 3D geometry of the SPT-N value. This method involves quantitatively testing the reliability of SGS and selecting the realizations with a high estimation accuracy. Boring tests were performed for validation, and the proposed method yielded more accurate prediction results and reproduced the spatial distribution of geotechnical information more effectively than the conventional geostatistical approach.

The influence of consumption values toward food delivery services on consumer attitudes, usage intention and willingness to pay (외식기업의 배달서비스에 대한 소비가치가 태도, 이용의도 및 지불의도에 미치는 영향)

  • Ki, SeRa;Kim, ChangSik;Jang, YoonJung;Ham, Sunny
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.15 no.4
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    • pp.159-171
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    • 2019
  • The purpose of this study was to understand the influence of research of consumers' consumption values and toward usage attitude, usage intention and willingness to pay of modern people. The study is a consumer research about food delivery services which is rapidly grown up due to recent transformation on a modern dietary life. This study was based on the main survey had conducted from 23th May 2019 to 26th May 2019 by 336 consumers, aged 18 and older, who had experienced Food delivery services in the past. Statistical analysis was performed by using the IBM SPSS v.25.0. In summary, the results of this study are as follows. First, consumption values of food delivery services had a positive influence on usage attitude. Consumption values were catagorized in five sub-values: functional value, social value, emotional value, epistemic value, and conditional value, all of which were found to be significant in affecting on usage attitude. Second, usage attitude toward food delivery services had a positive influence on usage intention. Third, usage attitude toward food delivery services had a positive influence on willingness to pay. Fourth, usage intention of food delivery services had a positive influence on willingness to pay. The results of the study renders industrial and academic implications to the area of Food delivery services industry.

Comparison of Dimension Reduction Methods for Time Series Factor Analysis: A Case Study (Value at Risk의 사후검증을 통한 다변량 시계열자료의 차원축소 방법의 비교: 사례분석)

  • Lee, Dae-Su;Song, Seong-Joo
    • The Korean Journal of Applied Statistics
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    • v.24 no.4
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    • pp.597-607
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    • 2011
  • Value at Risk(VaR) is being widely used as a simple tool for measuring financial risk. Although VaR has a few weak points, it is used as a basic risk measure due to its simplicity and easiness of understanding. However, it becomes very difficult to estimate the volatility of the portfolio (essential to compute its VaR) when the number of assets in the portfolio is large. In this case, we can consider the application of a dimension reduction technique; however, the ordinary factor analysis cannot be applied directly to financial data due to autocorrelation. In this paper, we suggest a dimension reduction method that uses the time-series factor analysis and DCC(Dynamic Conditional Correlation) GARCH model. We also compare the method using time-series factor analysis with the existing method using ordinary factor analysis by backtesting the VaR of real data from the Korean stock market.

Estimation of VaR Using Extreme Losses, and Back-Testing: Case Study (극단 손실값들을 이용한 VaR의 추정과 사후검정: 사례분석)

  • Seo, Sung-Hyo;Kim, Sung-Gon
    • The Korean Journal of Applied Statistics
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    • v.23 no.2
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    • pp.219-234
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    • 2010
  • In index investing according to KOSPI, we estimate Value at Risk(VaR) from the extreme losses of the daily returns which are obtained from KOSPI. To this end, we apply Block Maxima(BM) model which is one of the useful models in the extreme value theory. We also estimate the extremal index to consider the dependency in the occurrence of extreme losses. From the back-testing based on the failure rate method, we can see that the model is adaptable for the VaR estimation. We also compare this model with the GARCH model which is commonly used for the VaR estimation. Back-testing says that there is no meaningful difference between the two models if we assume that the conditional returns follow the t-distribution. However, the estimated VaR based on GARCH model is sensitive to the extreme losses occurred near the epoch of estimation, while that on BM model is not. Thus, estimating the VaR based on GARCH model is preferred for the short-term prediction. However, for the long-term prediction, BM model is better.