• The Journal of Bigdata
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• v.5 no.2
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• pp.135-143
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• 2020

This paper proposes a pre-processing method and a dimensional reduction method in the analysis of shopping carts where there are many correlations between variables when dividing the types of consumers in the agri-food consumer panel data. Cluster analysis is a widely used method for dividing observational objects into several clusters in multivariate data. However, cluster analysis through dimensional reduction may be more effective when several variables are related. In this paper, the food consumption data surveyed of 1,987 households was clustered using the K-means method, and 17 variables were re-selected to divide it into the clusters. Principal component analysis and factor analysis were compared as the solution for multicollinearity problems and as the way to reduce dimensions for clustering. In this study, both principal component analysis and factor analysis reduced the dataset into two dimensions. Although the principal component analysis divided the dataset into three clusters, it did not seem that the difference among the characteristics of the cluster appeared well. However, the characteristics of the clusters in the consumption pattern were well distinguished under the factor analysis method.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.889-897
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• 2014

With the development of wireless communication and sensor technology, sensor network applications in various fields have been applied. To minimize the power consumption of sensors in sensor network is one of the important factors in oder to extend the system life. The power consumption of each sensor within sensor network can be different depending on the communication method between head(sink) node and its node. In this paper, we propose a new hierarchical communication method to minimize the power consumption of each sensor. The proposed method divides the area of sensor network into four areas using divide-and-conquer method and selects the nearest node to head node in each area as a child node of the node. Next the hierarchical tree in the same way is constructed recursively until each area is no longer divided. Each sensor can communicate to head node using this hierarchical tree. The proposed results were compared with the previous methods through simulation, and showed excellent results in the energy efficiency of sensor network.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.69-75
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• 2014

A novel reversible data hiding method using pixel value ordering and prediction error expansion in the sub-block is resented in this paper. For each non-overlapping $2{\times}2$ sub-block, we divide into two groups. In the min group, the lowest value is changed to embed a secret bit and the highest value is changed in the max group. The experimental results show that the proposed method achieves a good visual quality and high capacity. The proposed method can embed 13,900 bits on average, it is higher 4,553 bits than the previous method and the visual quality is maintained 31.39dB on average.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.741-746
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• 2005

This paper proposes a method for designing layout on the yard and evaluating alternative designs of the layout by applying simulation The design method is based on the concepts of the conventional port container terminal with yard layout. In general, yard design of the container terminal consists of the two major parts. One is to divide yard area between the number of sections and runs and the other is to decide the number of equipment including yard truck and yard crane. In the past days, this design was depended on the experience of the terminal operator and the reproduction of the conventional terminal layout because it is a very complex problem to be considering facilities and equipments. In this paper, we suggest a design method as a conceptual procedure used simulation method The number of sections and runs on yard area, the number of yard truck per container crane, and the number of yard crane per run are decided using simulation In addition, the traffic flow among blocks on yard layout is estimated in terms of rate.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.5
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• pp.266-279
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• 2003

In this paper, we propose machine printed character recognition methods which utilize the character type information and divide the character clusters. The characters are subdivided into a total of seven types, of which six types are for Hangul according to the grapheme combination fashions and one type for English characters, numerals, and symbols. According to the character type, we separate input character image into several recognition units and recognize them by using the direction angle feature. The recognition for each character type is completed by combining recognition units which are recognized by neural networks respectively For combining a total of seven character recognizers, we implemented seven methods such as switching method, integrating method, and their several variants. As experimental results, we obtained 98.2% recognition rate of simple switching method, 90.54% of integrating one, and between 97.35% and 98.65% of five variants.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.32-41
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• 1994

To solve the frequency variation of speech patterns which consist of LPC sequences, new membership function view from LPC, spectrum and the relations between the order of LPC and spectrum is proposed. To solve the time variation, multi-secation equi-segmentation method which equally divide the speech section into several section are applied. False recognition mainly occur at time when the same syllable is placed at the same utterance. To reduce the error, fuzzy inference is executed using the proposed membership function and weights are assigned into sectional certainty and then the decision method for recognized the section up to the third candidate. To testify the validation of this method, we experimented the recognition test of 28 DDD area names. The recognition rate of the fuzzy inference by the triangle membership function is $92\%$. That of the combined method of the fuzzy inference and the dicision method is $92.9\%$ and that of fuzzy inference by the proposed membership funtion is $93.8\%$.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.773-777
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• 2009

In recent years, the field of synthesizing voice has been developed rapidly, and the technologies such as reading aloud an email or sound guidance of a car navigation system are used in various scenes of our life. The sound quality is monotonous like reading news. It is preferable for a text such as a novel to be read by the voice that expresses emotions wealthily. Therefore, we have been trying to develop a system reading aloud novels automatically that are expressed clear emotions comparatively such as juvenile literature. At first it is necessary to identify emotions expressed in a sentence in texts in order to make a computer read texts with an emotionally expressive voice. A method on the basis of the meaning interpretation that utilized artificial intelligence technology for a method to specify emotions of texts is thought, but it is very difficult with the current technology. Therefore, we propose a method to determine only emotion every sentence in a novel by a simpler way. This method determines the emotion of a sentence according to an emotion that words such as a verb in a Japanese verb sentence, and an adjective and an adverb in a adjective sentence, have. The emotional characteristics that these words have are prepared beforehand as a emotional words dictionary by us. The emotions used here are seven types: "joy," "sorrow," "anger," "surprise," "terror," "aversion" or "neutral."

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.944-951
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• 2004

In this paper, we proposed the method of the characteristic impedance and effective dielectric constant calculations of the shielded microstrip line with ground aperture using conformal mapping method. This method has advantages that can calculate the transmission parameters without using any other numerical method because present the closed form equations. First of all, we supposed the signal propagate with the microstrip mode(Quasi-TEM) and calculated the capacitance divide by three sections and calculated the characteristic impedance and effective dielectric constant using calculated capacitances. From the HFSS simulation result, calculated result was very similar to the simulation result within the five percent error range.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.997-1006
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• 2019

To overcome the difficulties and inefficiencies of the existing power analysis attack, we try to extract the secret key embedded in a cryptographic device using attack model based on MLP(Multi-Layer Perceptron) method. The target of our proposed power analysis attack is the AES-128 encryption module implemented on an 8-bit processor XMEGA128. We use the divide-and-conquer method in bytes to recover the whole 16 bytes secret key. As a result, the MLP-based power analysis attack can extract the secret key with the accuracy of 89.51%. Additionally, this MLP model has the 94.51% accuracy when the pre-processing method on power traces is applied. Compared to the machine leaning-based model SVM(Support Vector Machine), we show that the MLP can be a outstanding method in power analysis attacks due to excellent ability for feature extraction.

• Journal of Engineering Education Research
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• v.25 no.3
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• pp.3-10
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• 2022

An educator may utilize various pedagogies such as hands-on practice, practicum, and project-based learning to enhance a student's competency. Among various pedagogies, project-based learning is one of the well-known pedagogies that may provide similar on-the-job experience. In general, an educator may divide the students into small groups and assign tasks to check students' cooperation skills and achievements during project-based learning. However, an educator may experience difficulties operating project-based learning due to the COVID-19 pandemic. Most of the team activities are done in non-face-to-face meetings, and as a consequence, the educator may not find an underachieving team easily and cannot intervene appropriately. This study introduces a rigorous analysis method to evaluate team activities to analyze individual students' participation and contributions. First, this study develops evaluation rubrics by conducting questionnaires to professors and students to find an appropriate weight value for the evaluation scale. Then, this research introduces an analysis environment to evaluate students automatically. The analysis environment collects dialog data from social network services and measures interactions among students in a team. After measuring interactions, the environment generates a report to visualize the team activities. We applied the proposed method and environment to the capstone design course to show the effectiveness of the method and environment. Based on the case study, the environment showed that the analysis method could easily indicate the teams' activities and check the level of participation.