This paper proposes a method for estimating the acquisition status of students’ graph comprehension ability based on their descriptive answer text. Applying the three-level of graph comprehension theory, we designed a method to categorize students’ graph comprehension ability into three levels. The categorization is based on two metrics: 1) degree-a statistic of co-occurrence networks measuring of variety, and 2) level of graph comprehension-frequency of use of words indicating degree adverbs and words indicating trends. We then designed an “expression-development map” based on these quantities and classified students’ graph comprehension abilities according to which of the four quadrants they belonged to. To confirm the validity of the designed it, we applied the map to surveyed descriptive answer text for nine types of graph generated by elementary, junior/senior high school, and university students. The results showed that the descriptions became more sophisticated as students progressed through educational stages, indicating the validity of the map.

Weather map recognition is a complex image recognition task that requires two cognitive processes: the interpretation of symbols and future predictions. Recent advancements in multimodal AI have shown the potential to solve such complex tasks. This research uses ChatGPT, a type of multimodal AI, to validate the recognition performance of weather map images and proposes prompt engineering for more accurate recognition. Weather map recognition is a problem that is also featured in the Common University Entrance Test. If weather maps can be recognized, automatic grading and question generation become possible, leading to learning support. Furthermore, it is expected that weather commentary text can be automatically generated from weather maps. Therefore, weather map image recognition is an important task, but it requires not only recognizing time-series changes in local weather data but also recognizing information on large-scale weather patterns such as pressure pattern and making future predictions. In this research, we use ChatGPT4-Vision, a multimodal AI, to validate the recognition performance of weather map images. We investigate whether it can answer questions about weather maps from university entrance exams and generate weather commentary text from weather map images. By conducting multiple experiments with varying tasks and information in the prompts, and evaluating the accuracy of the generated commentaries, we propose and validate improvements in reading performance through prompt engineering.

In machine learning, one of the methods to solve multiclass classification problems is a framework called Error-Correcting Output Codes (ECOC), which constructs a multiclass classifier by combining a lot of binary classifiers. ECOC assigns binary codewords to each category, and the multiclass classification performance varies depending on the code. In this study, we treat each element of the codeword as a random variable and evaluate the average performance of ECOC. As a result, for$M$class classification if the number of binary classifiers is$O(\log M)$, then the average error probability of various codes approaches that of MAP estimation. We show that the important points are the ratio between the number of binary classifiers and$\log M$and the difference between the maximum posterior probability and the second highest posterior probability for the categories.

Error-correcting output coding (ECOC) is a method for constructing a multi-valued classifier using a combination of given binary classifiers. ECOC can estimate the correct category by other binary classifiers even if the output of some binary classifiers is incorrect based on the framework of the coding theory. The code word table representing the combination of these binary classifiers is important in ECOC. ECOC is known to perform well experimentally on real data. However, the complexity of the classification problem makes it difficult to analyze the classification performance in detail. For this reason, theoretical analysis of ECOC has not been conducted. In this study, if a binary classifier outputs the estimated posterior probability with errors, then this binary classifier is said to be noisy. In contrast, if a binary classifier outputs the true posterior probability, then this binary classifier is said to be noiseless. For a theoretical analysis of ECOC, we discuss the optimality for the code word table with noiseless binary classifiers and the error rate for one with noisy binary classifiers. This evaluation result shows that the Hamming distance of the code word table is an important indicator.

Consider M-valued (M$\geq$3) classification systems realized by combination of N(N$\geq\lceil\log_{2}$M$\rceil$) binary classifiers. Such a construction method is called an Error Correcting Output Code (ECOC). First, focusing on a Reed-Muller (RM) code, we derive a modified RM (mRM) code to make it suitable for the ECOC. Using the mRM code and the Hadamard matrix, we introduce a simplex code which is one of the powerful equidistant codes. Next, from the viewpoint of system evaluation model, we evaluate the ECOC by using constructive coding described above. We show that they have desirable properties such as Flexible, Elastic, and Effective Elastic as M becomes large, by employing analytical formulas and experiments.

Error-Correcting Output Coding (ECOC) is a method for constructing a multi-valued classifier using a combination of binary classifiers. The effectiveness of ECOC for multivalued classification problems has been demonstrated by many experimental evaluations. Therefore, classification performance have strongly depended on the data under consideration, and it is not clear what kind of combinations of binary classifiers have good performance. Motivated by this fact, the authors have clarified the best combination of binary classifiers that makes ECOC, assuming a situation in which each binary classifier can estimate the true posterior probability. They also have proposed a total framework for analytical evaluation when a binary classifier outputs an estimated posterior probability that approximates the true posterior probability. These studies established a framework for evaluating the theoretical performance of ECOC.Based on these findings, this study discusses the theoretical performance of ECOC from the upper bound perspective. The results showed that increasing the Hamming distance between code words can blackuce the error rate. We then evaluate various combinations of binary classifiers based on analytical evaluation.

With the development of IoT technology, it has become possible to accumulate and regularly measure multidimensional time-series data. In this study, we focus on the usage of multidimensional time-series data from printer products' log data and propose a method for its analysis. In addition to the number of sheets printed by each customer, the log data includes various time-series information such as the amount of remaining toner, the number of stoppages that occur, and the activation times. To utilize these data for business purposes, it is desirable to construct a model for predicting future changes in use characteristics for each customer. In this study, we apply the random forest algorithm to predict such changes. However, if all measurable features of the problem are included, the model becomes complex and cannot be interpreted. Although the accuracy is relatively high if an appropriate learning algorithm is applied, the complex model tends to overfit the training data. In this paper, we propose a method to select the modeling features that can be interpreted by graph mining while maintaining accuracy. This would enable us to interpret the data at the field level and discover the hypotheses that are necessary for planned marketing policies. Finally, the proposed method is applied to real data and its efficacy is demonstrated.

To solve multiple classification problems with $M (\geq$ 3) categories, many studies have been devoted using $N (\geq\ \lceil\log_{2}M\rceil)$ binary $(\{0,1\})$ classifiers, where these systems are known as binary Error-Correcting Output Codes (binary ECOC). As an extended version of the binary ECOC, the ternary $(\{0,\ *,\ 1\})$ ECOC have also been discussed, where ternary classifiers classify data into positive examples when the element is 1, into negative examples when the element is 0, and no classification when the element is $*$. In this paper, we discuss the ternary ECOC system from the view point of the system evaluation model based on rate-distortion function. First, we discuss a table of M code words with length N which is given by a ternary matrix W of M rows and N columns. Next, by leveraging the benchmark data for multiclass document classification which is widely used in Japan, the relationships between the probability of classification error Peand the number of the ternary classifiers N for a given M are experimentally investigated. In addition, by assuming the M-dimensional Normal distribution for a classification data model, the relationship between Peand N for a given M is also examined. Finally, we show by the system evaluation model that the ternary ECOC systems have desirable properties such as “Flexible”, “Elastic”, and “Effective Elastic”, when M becomes large.