• Title/Summary/Keyword: 선택적 학습률

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Exploration of Features of Korean Eighth Grade Students' Achievement and Curriculum Matching in TIMSS 2015 Earth Science (TIMSS 2015 중학교 2학년 지구과학 영역에 대한 우리나라 학생들의 성취 특성 및 교육과정 연계성 탐색)

  • Kwak, Youngsun
    • Journal of The Korean Association For Science Education
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    • v.37 no.1
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    • pp.9-16
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    • 2017
  • The result of TIMSS 2015 was announced at the end of 2016. In this research, we conducted test-curriculum matching analysis for 8th grade earth science and analyzed Korean students' percentage of correct answers and responses for TIMSS earth science test items. According to the results, Korean students showed high percentage of correct answers when the item topics are covered in the 2009 revised science curriculum, and Korean students revealed their weakness in constructed response items since the percentage for correct answers on constructed response items is half that of multiple choice items. Depending on the earth science topic, for 'solid earth' area, which includes earth's structure and physical features, as well as earth's processes and history, students showed high percentage of correct answers for multiple choice items. Students, however, showed low percentage of correct answers for items that require applying knowledge to everyday situations and connecting with other areas of science such as biology. For 'atmosphere and ocean' areas, which include earth's processes and cycles, students showed low percentage of scores for climate comparison between regions, features of global warming, etc. For the area of 'universe', students showed high percentage of scores for the earth's rotation and revolution, the moon's gravity, and so on because they have learned these topics since primary school. Discussed in the conclusion are ways to secure content connection between the primary and middle school earth science curriculums, ways to develop students' science-inquiry related competencies, and so on to improve middle school earth science curriculum as well as teaching and learning.

A User Driven Adaptive Bandwidth Video Streaming System (사용자 기반 가변 대역폭 영상 스트리밍 시스템)

  • Chung, Yeongjee;Ozturk, Yusuf
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.4
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    • pp.825-840
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    • 2015
  • Adaptive bitrate (ABR) streaming technology has become an important and prevalent feature in many multimedia delivery systems, with content providers such as Netflix and Amazon using ABR streaming to increase bandwidth efficiency and provide the maximum user experience when channel conditions are not ideal. Where such systems could see improvement is in the delivery of live video with a closed loop cognitive control of video encoding. In this paper, we present streaming camera system which provides spatially and temporally adaptive video streams, learning the user's preferences in order to make intelligent scaling decisions. The system employs a hardware based H.264/AVC encoder for video compression. The encoding parameters can be configured by the user or by the cognitive system on behalf of the user when the bandwidth changes. A cognitive video client developed in this study learns the user's preferences(i.e. video size over frame rate) over time and intelligently adapts encoding parameters when the channel conditions change. It has been demonstrated that the cognitive decision system developed has the ability to control video bandwidth by altering the spatial and temporal resolution, as well as the ability to make scaling decisions.

Emotion Recognition Method using Physiological Signals and Gestures (생체 신호와 몸짓을 이용한 감정인식 방법)

  • Kim, Ho-Duck;Yang, Hyun-Chang;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.3
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    • pp.322-327
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    • 2007
  • Researchers in the field of psychology used Electroencephalographic (EEG) to record activities of human brain lot many years. As technology develope, neural basis of functional areas of emotion processing is revealed gradually. So we measure fundamental areas of human brain that controls emotion of human by using EEG. Hands gestures such as shaking and head gesture such as nodding are often used as human body languages for communication with each other, and their recognition is important that it is a useful communication medium between human and computers. Research methods about gesture recognition are used of computer vision. Many researchers study emotion recognition method which uses one of physiological signals and gestures in the existing research. In this paper, we use together physiological signals and gestures for emotion recognition of human. And we select the driver emotion as a specific target. The experimental result shows that using of both physiological signals and gestures gets high recognition rates better than using physiological signals or gestures. Both physiological signals and gestures use Interactive Feature Selection(IFS) for the feature selection whose method is based on a reinforcement learning.

Hybrid Method using Frame Selection and Weighting Model Rank to improve Performance of Real-time Text-Independent Speaker Recognition System based on GMM (GMM 기반 실시간 문맥독립화자식별시스템의 성능향상을 위한 프레임선택 및 가중치를 이용한 Hybrid 방법)

  • 김민정;석수영;김광수;정호열;정현열
    • Journal of Korea Multimedia Society
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    • v.5 no.5
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    • pp.512-522
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    • 2002
  • In this paper, we propose a hybrid method which is mixed with frame selection and weighting model rank method, based on GMM(gaussian mixture model), for real-time text-independent speaker recognition system. In the system, maximum likelihood estimation was used for GMM parameter optimization, and maximum likelihood was used for recognition basically Proposed hybrid method has two steps. First, likelihood score was calculated with speaker models and test data at frame level, and the difference is calculated between the biggest likelihood value and second. And then, the frame is selected if the difference is bigger than threshold. The second, instead of calculated likelihood, weighting value is used for calculating total score at each selected frame. Cepstrum coefficient and regressive coefficient were used as feature parameters, and the database for test and training consists of several data which are collected at different time, and data for experience are selected randomly In experiments, we applied each method to baseline system, and tested. In speaker recognition experiments, proposed hybrid method has an average of 4% higher recognition accuracy than frame selection method and 1% higher than W method, implying the effectiveness of it.

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Text-Independent Speaker Identification System Using Speaker Decision Network Based on Delayed Summing (지연누적에 기반한 화자결정회로망이 도입된 구문독립 화자인식시스템)

  • 이종은;최진영
    • Journal of the Korean Institute of Intelligent Systems
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    • v.8 no.2
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    • pp.82-95
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    • 1998
  • In this paper, we propose a text-independent speaker identification system which has a classifier composed of two parts; to calculate the degree of likeness of each speech frame and to select the most probable speaker from the entire speech duration. The first part is realized using RBFN which is selforganized through learning and in the second part the speaker is determined using a con-tbination of MAXNET and delayed summings. And we use features from linear speech production model and features from fractal geometry. Closed-set speaker identification experiments on 13 male homogeneous speakers show that the proposed techniques can achieve the identification ratio of 100% as the number of delays increases.

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Generation of Efficient Fuzzy Classification Rules Using Evolutionary Algorithm with Data Partition Evaluation (데이터 분할 평가 진화알고리즘을 이용한 효율적인 퍼지 분류규칙의 생성)

  • Ryu, Joung-Woo;Kim, Sung-Eun;Kim, Myung-Won
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.1
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    • pp.32-40
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    • 2008
  • Fuzzy rules are very useful and efficient to describe classification rules especially when the attribute values are continuous and fuzzy in nature. However, it is generally difficult to determine membership functions for generating efficient fuzzy classification rules. In this paper, we propose a method of automatic generation of efficient fuzzy classification rules using evolutionary algorithm. In our method we generate a set of initial membership functions for evolutionary algorithm by supervised clustering the training data set and we evolve the set of initial membership functions in order to generate fuzzy classification rules taking into consideration both classification accuracy and rule comprehensibility. To reduce time to evaluate an individual we also propose an evolutionary algorithm with data partition evaluation in which the training data set is partitioned into a number of subsets and individuals are evaluated using a randomly selected subset of data at a time instead of the whole training data set. We experimented our algorithm with the UCI learning data sets, the experiment results showed that our method was more efficient at average compared with the existing algorithms. For the evolutionary algorithm with data partition evaluation, we experimented with our method over the intrusion detection data of KDD'99 Cup, and confirmed that evaluation time was reduced by about 70%. Compared with the KDD'99 Cup winner, the accuracy was increased by 1.54% while the cost was reduced by 20.8%.

The Method of the Evaluation of Verbal Lexical-Semantic Network Using the Automatic Word Clustering System (단어클러스터링 시스템을 이용한 어휘의미망의 활용평가 방안)

  • Kim, Hae-Gyung;Song, Mi-Young
    • Korean Journal of Oriental Medicine
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    • v.12 no.3 s.18
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    • pp.1-15
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    • 2006
  • For the recent several years, there has been much interest in lexical semantic network. However, it seems to be very difficult to evaluate the effectiveness and correctness of it and invent the methods for applying it into various problem domains. In order to offer the fundamental ideas about how to evaluate and utilize lexical semantic networks, we developed two automatic word clustering systems, which are called system A and system B respectively. 68,455,856 words were used to learn both systems. We compared the clustering results of system A to those of system B which is extended by the lexical-semantic network. The system B is extended by reconstructing the feature vectors which are used the elements of the lexical-semantic network of 3,656 '-ha' verbs. The target data is the 'multilingual Word Net-CoreNet'.When we compared the accuracy of the system A and system B, we found that system B showed the accuracy of 46.6% which is better than that of system A, 45.3%.

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Characteristics of Wheat Flour Dough and Noodles with Amylopectin Content and Hydrocolloids (아밀로펙틴 함량 변화와 하이드로콜로이드 첨가에 의한 밀가루 반죽 및 국수의 특성)

  • Cho, Young-Hwa;Shim, Jae-Yong;Lee, Hyeon-Gyu
    • Korean Journal of Food Science and Technology
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    • v.39 no.2
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    • pp.138-145
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    • 2007
  • The effects of amylopectin and hydrocolloid (locust bean gum and guar gum) content on wheat flour dough and noodle properties were investigated. As the amount of amylopectin increased, the water absorption rate (farinograph), the tension (tension test), the gel stability (freeze-thawing treatment), and the springiness and the cohesiveness (TPA) increased, but the pasting temperature (RVA), the lightness and yellowness (color measurement), and the hardness (TPA) tended to decrease. In sensory evaluations, the scores for cohesiveness, springiness, and acceptability of cooked noodle increased as the proportion of amylopectin increased. The proper combination of amylose/amylopectin ratio and hydrocolloids improved the freeze-thaw stability and the sensory acceptability of wheat flour dough and noodle.

Activity Recognition based on Multi-modal Sensors using Dynamic Bayesian Networks (동적 베이지안 네트워크를 이용한 델티모달센서기반 사용자 행동인식)

  • Yang, Sung-Ihk;Hong, Jin-Hyuk;Cho, Sung-Bae
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.1
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    • pp.72-76
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    • 2009
  • Recently, as the interest of ubiquitous computing has been increased there has been lots of research about recognizing human activities to provide services in this environment. Especially, in mobile environment, contrary to the conventional vision based recognition researches, lots of researches are sensor based recognition. In this paper we propose to recognize the user's activity with multi-modal sensors using hierarchical dynamic Bayesian networks. Dynamic Bayesian networks are trained by the OVR(One-Versus-Rest) strategy. The inferring part of this network uses less calculation cost by selecting the activity with the higher percentage of the result of a simpler Bayesian network. For the experiment, we used an accelerometer and a physiological sensor recognizing eight kinds of activities, and as a result of the experiment we gain 97.4% of accuracy recognizing the user's activity.

Self-optimizing feature selection algorithm for enhancing campaign effectiveness (캠페인 효과 제고를 위한 자기 최적화 변수 선택 알고리즘)

  • Seo, Jeoung-soo;Ahn, Hyunchul
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.173-198
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    • 2020
  • For a long time, many studies have been conducted on predicting the success of campaigns for customers in academia, and prediction models applying various techniques are still being studied. Recently, as campaign channels have been expanded in various ways due to the rapid revitalization of online, various types of campaigns are being carried out by companies at a level that cannot be compared to the past. However, customers tend to perceive it as spam as the fatigue of campaigns due to duplicate exposure increases. Also, from a corporate standpoint, there is a problem that the effectiveness of the campaign itself is decreasing, such as increasing the cost of investing in the campaign, which leads to the low actual campaign success rate. Accordingly, various studies are ongoing to improve the effectiveness of the campaign in practice. This campaign system has the ultimate purpose to increase the success rate of various campaigns by collecting and analyzing various data related to customers and using them for campaigns. In particular, recent attempts to make various predictions related to the response of campaigns using machine learning have been made. It is very important to select appropriate features due to the various features of campaign data. If all of the input data are used in the process of classifying a large amount of data, it takes a lot of learning time as the classification class expands, so the minimum input data set must be extracted and used from the entire data. In addition, when a trained model is generated by using too many features, prediction accuracy may be degraded due to overfitting or correlation between features. Therefore, in order to improve accuracy, a feature selection technique that removes features close to noise should be applied, and feature selection is a necessary process in order to analyze a high-dimensional data set. Among the greedy algorithms, SFS (Sequential Forward Selection), SBS (Sequential Backward Selection), SFFS (Sequential Floating Forward Selection), etc. are widely used as traditional feature selection techniques. It is also true that if there are many risks and many features, there is a limitation in that the performance for classification prediction is poor and it takes a lot of learning time. Therefore, in this study, we propose an improved feature selection algorithm to enhance the effectiveness of the existing campaign. The purpose of this study is to improve the existing SFFS sequential method in the process of searching for feature subsets that are the basis for improving machine learning model performance using statistical characteristics of the data to be processed in the campaign system. Through this, features that have a lot of influence on performance are first derived, features that have a negative effect are removed, and then the sequential method is applied to increase the efficiency for search performance and to apply an improved algorithm to enable generalized prediction. Through this, it was confirmed that the proposed model showed better search and prediction performance than the traditional greed algorithm. Compared with the original data set, greed algorithm, genetic algorithm (GA), and recursive feature elimination (RFE), the campaign success prediction was higher. In addition, when performing campaign success prediction, the improved feature selection algorithm was found to be helpful in analyzing and interpreting the prediction results by providing the importance of the derived features. This is important features such as age, customer rating, and sales, which were previously known statistically. Unlike the previous campaign planners, features such as the combined product name, average 3-month data consumption rate, and the last 3-month wireless data usage were unexpectedly selected as important features for the campaign response, which they rarely used to select campaign targets. It was confirmed that base attributes can also be very important features depending on the type of campaign. Through this, it is possible to analyze and understand the important characteristics of each campaign type.