• Title/Summary/Keyword: Multi-modal Data

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Structural Analysis of Spaceborne Two-axis Gimbal-type Antenna of Compact Advanced Satellite (차세대 중형위성용 2축 짐벌식 안테나의 구조해석)

  • Park, Yeon-Hyeok;You, Chang-Mok;Kang, Eun-Su;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.12 no.2
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    • pp.37-45
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    • 2018
  • A two-axis gimbal-type antenna for a Compact Advanced Satellite (CAS) is used to efficiently transmit high resolution image data to a ground station. In this study, we designed the structure of a two-axis gimbal-type antenna while applying a launch lock device to secure its structural safety under a launch environment. To validate the effectiveness of the structural design, a structural analysis of the antenna was performed. First, a modal analysis was performed to investigate the dynamic responses of the antenna with and without the mechanical constraints of the launch lock device. In addition, a quasi-static analysis was performed to confirm the structural safety of the antenna structure and bolt I/Fs between the antenna base and the satellite. The suitable range of constraint force on the launch lock device was also determined to ensure the structural safety and mechanical gapping of the ball & socket interfaces, which places multi-constraints on the azimuth and elevation stage of the antenna.

Flexible smart sensor framework for autonomous structural health monitoring

  • Rice, Jennifer A.;Mechitov, Kirill;Sim, Sung-Han;Nagayama, Tomonori;Jang, Shinae;Kim, Robin;Spencer, Billie F. Jr.;Agha, Gul;Fujino, Yozo
    • Smart Structures and Systems
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    • v.6 no.5_6
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    • pp.423-438
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    • 2010
  • Wireless smart sensors enable new approaches to improve structural health monitoring (SHM) practices through the use of distributed data processing. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While much of the technology associated with smart sensors has been available for nearly a decade, there have been limited numbers of fulls-cale implementations due to the lack of critical hardware and software elements. This research develops a flexible wireless smart sensor framework for full-scale, autonomous SHM that integrates the necessary software and hardware while addressing key implementation requirements. The Imote2 smart sensor platform is employed, providing the computation and communication resources that support demanding sensor network applications such as SHM of civil infrastructure. A multi-metric Imote2 sensor board with onboard signal processing specifically designed for SHM applications has been designed and validated. The framework software is based on a service-oriented architecture that is modular, reusable and extensible, thus allowing engineers to more readily realize the potential of smart sensor technology. Flexible network management software combines a sleep/wake cycle for enhanced power efficiency with threshold detection for triggering network wide operations such as synchronized sensing or decentralized modal analysis. The framework developed in this research has been validated on a full-scale a cable-stayed bridge in South Korea.

Feasibility Study on Introduction of Piggy-back System by Applying Transport Database

  • Lee, Yong-Jae;Lee, Chulung;Kim, Yong-Hoon;Han, Seong-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.1
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    • pp.157-166
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    • 2022
  • In this study, The goal is to analyze the feasibility of introducing a Piggyback system that can reduce the time and cost incurred by transshipment work and improve the transportation speed when transporting complex cargo by rail. To this end, the feasibility analysis methodology is reviewed through domestic and international literature review. In order to quantitatively derive the feasibility analysis values, a transportation database was applied to develop a freight transport simulation model and a freight demand prediction model for major freight transport O-D routes with a transportation distance of 200 km or more. As a result of analyzing economic feasibility by setting the analysis period to 15 years on the premise that the Piggyback System will be introduced on major cargo transport O-D routes in 2025, the NPV value was positive and the B/C value was 1.18, indicating that the Piggyback system was economical. The proposed research method can be meaningful data for establishing transportation policies that can improve the competitiveness of railroad transportation.

Layout optimization of wireless sensor networks for structural health monitoring

  • Jalsan, Khash-Erdene;Soman, Rohan N.;Flouri, Kallirroi;Kyriakides, Marios A.;Feltrin, Glauco;Onoufriou, Toula
    • Smart Structures and Systems
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    • v.14 no.1
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    • pp.39-54
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    • 2014
  • Node layout optimization of structural wireless systems is investigated as a means to prolong the network lifetime without, if possible, compromising information quality of the measurement data. The trade-off between these antagonistic objectives is studied within a multi-objective layout optimization framework. A Genetic Algorithm is adopted to obtain a set of Pareto-optimal solutions from which the end user can select the final layout. The information quality of the measurement data collected from a heterogeneous WSN is quantified from the placement quality indicators of strain and acceleration sensors. The network lifetime or equivalently the network energy consumption is estimated through WSN simulation that provides realistic results by capturing the dynamics of the wireless communication protocols. A layout optimization study of a monitoring system on the Great Belt Bridge is conducted to evaluate the proposed approach. The placement quality of strain gauges and accelerometers is obtained as a ratio of the Modal Clarity Index and Mode Shape Expansion values that are computed from a Finite Element model of the monitored bridge. To estimate the energy consumption of the WSN platform in a realistic scenario, we use a discrete-event simulator with stochastic communication models. Finally, we compare the optimization results with those obtained in a previous work where the network energy consumption is obtained via deterministic communication models.

Implementation of a Multimodal Controller Combining Speech and Lip Information (음성과 영상정보를 결합한 멀티모달 제어기의 구현)

  • Kim, Cheol;Choi, Seung-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.6
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    • pp.40-45
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    • 2001
  • In this paper, we implemented a multimodal system combining speech and lip information, and evaluated its performance. We designed speech recognizer using speech information and lip recognizer using image information. Both recognizers were based on HMM recognition engine. As a combining method we adopted the late integration method in which weighting ratio for speech and lip is 8:2. By the way, Our constructed multi-modal recognition system was ported on DARC system. That is, our system was used to control Comdio of DARC. The interrace between DARC and our system was done with TCP/IP socked. The experimental results of controlling Comdio showed that lip recognition can be used for an auxiliary means of speech recognizer by improving the rate of the recognition. Also, we expect that multi-model system will be successfully applied to o traffic information system and CNS (Car Navigation System).

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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.

Improved Transformer Model for Multimodal Fashion Recommendation Conversation System (멀티모달 패션 추천 대화 시스템을 위한 개선된 트랜스포머 모델)

  • Park, Yeong Joon;Jo, Byeong Cheol;Lee, Kyoung Uk;Kim, Kyung Sun
    • The Journal of the Korea Contents Association
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    • v.22 no.1
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    • pp.138-147
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    • 2022
  • Recently, chatbots have been applied in various fields and have shown good results, and many attempts to use chatbots in shopping mall product recommendation services are being conducted on e-commerce platforms. In this paper, for a conversation system that recommends a fashion that a user wants based on conversation between the user and the system and fashion image information, a transformer model that is currently performing well in various AI fields such as natural language processing, voice recognition, and image recognition. We propose a multimodal-based improved transformer model that is improved to increase the accuracy of recommendation by using dialogue (text) and fashion (image) information together for data preprocessing and data representation. We also propose a method to improve accuracy through data improvement by analyzing the data. The proposed system has a recommendation accuracy score of 0.6563 WKT (Weighted Kendall's tau), which significantly improved the existing system's 0.3372 WKT by 0.3191 WKT or more.

A Method of Comparing Risk Similarities Based on Multimodal Data (멀티모달 데이터 기반 위험 발생 유사성 비교 방법)

  • Kwon, Eun-Jung;Shin, WonJae;Lee, Yong-Tae;Lee, Kyu-Chul
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2019.05a
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    • pp.510-512
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    • 2019
  • Recently, there have been growing requirements in the public safety sector to ensure safety through detection of hazardous situations or preemptive predictions. It is noteworthy that various sensor data can be analyzed and utilized as a result of mobile device's dissemination, and many advantages can be used in terms of safety and security. An effective modeling technique is needed to combine sensor data generated by smart-phones and wearable devices to analyze users' moving patterns and behavioral patterns, and to ensure public safety by fusing location-based crime risk data provided.

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Korean Emotional Speech and Facial Expression Database for Emotional Audio-Visual Speech Generation (대화 영상 생성을 위한 한국어 감정음성 및 얼굴 표정 데이터베이스)

  • Baek, Ji-Young;Kim, Sera;Lee, Seok-Pil
    • Journal of Internet Computing and Services
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    • v.23 no.2
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    • pp.71-77
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    • 2022
  • In this paper, a database is collected for extending the speech synthesis model to a model that synthesizes speech according to emotions and generating facial expressions. The database is divided into male and female data, and consists of emotional speech and facial expressions. Two professional actors of different genders speak sentences in Korean. Sentences are divided into four emotions: happiness, sadness, anger, and neutrality. Each actor plays about 3300 sentences per emotion. A total of 26468 sentences collected by filming this are not overlap and contain expression similar to the corresponding emotion. Since building a high-quality database is important for the performance of future research, the database is assessed on emotional category, intensity, and genuineness. In order to find out the accuracy according to the modality of data, the database is divided into audio-video data, audio data, and video data.

A News Video Mining based on Multi-modal Approach and Text Mining (멀티모달 방법론과 텍스트 마이닝 기반의 뉴스 비디오 마이닝)

  • Lee, Han-Sung;Im, Young-Hee;Yu, Jae-Hak;Oh, Seung-Geun;Park, Dai-Hee
    • Journal of KIISE:Databases
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    • v.37 no.3
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    • pp.127-136
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    • 2010
  • With rapid growth of information and computer communication technologies, the numbers of digital documents including multimedia data have been recently exploded. In particular, news video database and news video mining have became the subject of extensive research, to develop effective and efficient tools for manipulation and analysis of news videos, because of their information richness. However, many research focus on browsing, retrieval and summarization of news videos. Up to date, it is a relatively early state to discover and to analyse the plentiful latent semantic knowledge from news videos. In this paper, we propose the news video mining system based on multi-modal approach and text mining, which uses the visual-textual information of news video clips and their scripts. The proposed system systematically constructs a taxonomy of news video stories in automatic manner with hierarchical clustering algorithm which is one of text mining methods. Then, it multilaterally analyzes the topics of news video stories by means of time-cluster trend graph, weighted cluster growth index, and network analysis. To clarify the validity of our approach, we analyzed the news videos on "The Second Summit of South and North Korea in 2007".